one of most common solvent used for crystallization is
Water
4228277
where the sample is heated strongly, and the accurate weight of a sample is plotted against the temperature. The amount of water driven off is then divided by the molar mass of water to obtain the number of molecules of water bound to the salt. Water is particularly common solvent to be found in crystals because it is small and polar. But "all" solvents can be found in some host crystals. Water is noteworthy because it is reactive, whereas other solvents such as benzene are considered to be chemically innocuous. Occasionally more than one solvent is found in a crystal,
Water of crystallization
4228278
and often the stoichiometry is variable, reflected in the crystallographic concept of "partial occupancy." It is common and conventional for a chemist to "dry" a sample with a combination of vacuum and heat "to constant weight." For other solvents of crystallization, analysis is conveniently accomplished by dissolving the sample in a deuterated solvent and analyzing the sample for solvent signals by NMR spectroscopy. Single crystal X-ray crystallography is often able to detect the presence of these solvents of crystallization as well. Other methods may be currently available. In the table below are indicated the number of molecules of water per
Water of crystallization
4228277
where the sample is heated strongly, and the accurate weight of a sample is plotted against the temperature. The amount of water driven off is then divided by the molar mass of water to obtain the number of molecules of water bound to the salt. Water is particularly common solvent to be found in crystals because it is small and polar. But "all" solvents can be found in some host crystals. Water is noteworthy because it is reactive, whereas other solvents such as benzene are considered to be chemically innocuous. Occasionally more than one solvent is found in a crystal,
Water of crystallization
19003127
point of view of sustainable chemistry since it does not produce by-products. Cyclopentyl methyl ether is used in organic synthesis, mainly as a solvent. However it is also useful in extraction, polymerization, crystallization and surface coating. Some examples of reactions where it acts as a solvent are: Cyclopentyl methyl ether Cyclopentyl methyl ether (CPME), also known as methoxycyclopentane, is hydrophobic ether solvent. A high boiling point of and preferable characteristics such as low formation of peroxides, relative stability under acidic and basic conditions, formation of azeotropes with water coupled with a narrow explosion range render CPME an alternative to other
Cyclopentyl methyl ether
4255321
heat of vaporization equals the difference in enthalpy. In simple words, the liquid is cooled by evaporating a part of it. In the sugar industry, vertical cooling crystallizers are used to exhaust the molasses in the last crystallization stage downstream of vacuum pans, prior to centrifugation. The massecuite enters the crystallizers at the top, and cooling water is pumped through pipes in counterflow. Another option is to obtain, at an approximately constant temperature, the precipitation of the crystals by increasing the solute concentration above the solubility threshold. To obtain this, the solute/solvent mass ratio is increased using the technique of
Crystallization
482757
(citrus terpenes) and in perfumes (ethanol). Water is a solvent for polar molecules and the most common solvent used by living things; all the ions and proteins in a cell are dissolved in water within a cell. Solvents find various applications in chemical, pharmaceutical, oil, and gas industries, including in chemical syntheses and purification processes. When one substance is dissolved into another, a solution is formed. This is opposed to the situation when the compounds are insoluble like sand in water. In a solution, all of the ingredients are uniformly distributed at a molecular level and no residue remains. A
Solvent
14613527
reactions with oxygen. Tetrahydrofuran (THF) at reflux is the most commonly employed solvent system, but photodissociation conditions at low temperature may also be used. Reactions employing polar MCPs are usually carried out in a polar solvent to facilitate formation of the TMM intermediate. Although rigorous exclusion of air and water is not required, it is generally preferred. For transition-metal catalyzed MCP reactions, the choice of catalyst and ligand system is key. Generally, phosphine or phosphite ligands are required in conjunction with a palladium(0) or nickel(0) source; the most common are Pd(dba) and Ni(cod). Tri(isopropyl)phosphine is the most common ligand used
Trimethylenemethane cycloaddition
4805456
Protic solvent In chemistry, a protic solvent is a solvent that has a hydrogen atom bound to an oxygen (as in a hydroxyl group) or a nitrogen (as in an amine group). In general terms, any solvent that contains a labile H is called a protic solvent. The molecules of such solvents readily donate protons (H) to reagents. Conversely, aprotic solvents cannot donate hydrogen. Polar protic solvents are often used to dissolve salts. In general, these solvents have high dielectric constants and high polarity. Common characteristics of protic solvents : Examples include water, most alcohols, formic acid, hydrogen fluoride, and
Protic solvent
6273643
perceived dangers related to their use in food preparation. s is forced through the green coffee beans which are then sprayed with water at high pressure to remove the caffeine. The caffeine can then be isolated for resale (e.g. to the pharmaceutical or beverage manufacturers) by passing the water through activated charcoal filters or by distillation, crystallization or reverse osmosis. Supercritical carbon dioxide is used to remove organochloride pesticides and metals from agricultural crops without adulterating the desired constituents from the plant matter in the herbal supplement industry. Supercritical carbon dioxide can be used as a more environmentally friendly solvent
Supercritical carbon dioxide
16538054
scale and involve both batch, fed batch or continuous operations. Reactors for enzymatic reactions are present that can be used with either water of organic solvents. Green chemistry is performed in explosion proof installations such as glass-lined chemical reactors (1 - 6.000 l scale) that are suited to perform under vacuum or under pressure. The Bio Base Europe Pilot Plant is also equipped with filter dryers for solvent extraction of liquids and solids. Downstream processing for the recovery of pure products after biochemical or chemical conversion involves various equipment for extraction, evaporation, demineralization, ion exchange, carbon treatment, crystallization, spray drying,
Bio Base Europe
17344209
silver and reported that the Si–O–Si bond number increased with increasing silver concentration and this resulted in structural densification. It was also observed that quartz and metallic silver crystallization increased with the increase in silver content in bioactive glass while hydroxyapatite crystallization decreased. There is wide agreement about the versatility of the sol–gel technique to synthesize inorganic materials and it has been shown to be suitable for production of a variety of bioactive glasses. However, the method is also limited in terms of compositions that can be produced. Moreover remaining water or residual solvent content may result in complications of
Synthesis of bioglass
2114652
When surfactants are present above the critical micelle concentration (CMC), they can act as emulsifiers that will allow a compound that is normally insoluble (in the solvent being used) to dissolve. This occurs because the insoluble species can be incorporated into the micelle core, which is itself solubilized in the bulk solvent by virtue of the head groups' favorable interactions with solvent species. The most common example of this phenomenon is detergents, which clean poorly soluble lipophilic material (such as oils and waxes) that cannot be removed by water alone. Detergents clean also by lowering the surface tension of water,
Micelle
2913095
recover samples is removal of the organic solvent by evaporation followed by addition of water (to dissolve DMSO) and cryodesiccation to remove both DMSO and water. Reactions conducted in DMSO are often diluted with water to precipitate or phase-separate products. The relatively high freezing point of DMSO, , means that at, or just below, room temperature it is a solid, which can limit its utility in some chemical processes (e.g. crystallization with cooling). In its deuterated form (DMSO-d), it is a useful solvent for NMR spectroscopy, again due to its ability to dissolve a wide range of analytes, the simplicity
Dimethyl sulfoxide
3521778
and health. White spirit White spirit (UK) or mineral spirits (US, Canada), also known as mineral turpentine (AU/NZ), turpentine substitute, petroleum spirits, solvent naphtha (petroleum), Varsol, Stoddard solvent, or, generically, "paint thinner", is a petroleum-derived clear liquid used as a common organic solvent in painting. A mixture of aliphatic, open-chain or alicyclic C7 to C12 hydrocarbons, white spirit is insoluble in water and is used as an extraction solvent, as a cleaning solvent, as a degreasing solvent and as a solvent in aerosols, paints, wood preservatives, lacquers, varnishes, and asphalt products. In western Europe about 60% of the total white
White spirit
3521765
White spirit White spirit (UK) or mineral spirits (US, Canada), also known as mineral turpentine (AU/NZ), turpentine substitute, petroleum spirits, solvent naphtha (petroleum), Varsol, Stoddard solvent, or, generically, "paint thinner", is a petroleum-derived clear liquid used as a common organic solvent in painting. A mixture of aliphatic, open-chain or alicyclic C7 to C12 hydrocarbons, white spirit is insoluble in water and is used as an extraction solvent, as a cleaning solvent, as a degreasing solvent and as a solvent in aerosols, paints, wood preservatives, lacquers, varnishes, and asphalt products. In western Europe about 60% of the total white spirit consumption
White spirit
6466294
can use any liquid compatible with the process, provided it has the appropriate vapor pressure properties, as the sealant liquid. Although the most common sealant is water, almost any liquid can be used. The second most common is oil. Since oil has a very low vapor pressure, oil-sealed liquid-ring vacuum pumps are typically air-cooled. For dry chlorine gas applications concentrated sulfuric acid is used. The ability to use any liquid allows the liquid-ring vacuum pump to be ideally suited for solvent (vapor) recovery. If a process, such as distillation or a vacuum dryer, is generating toluene vapors, for example, then
Liquid-ring pump
3358429
it can help with cold starting an engine at sub-zero temperatures. For the same reason it is also used as a component of the fuel mixture for carbureted compression ignition model engines. In this way diethyl ether is very similar to one of its precursors, ethanol. Diethyl ether is a common laboratory aprotic solvent. It has limited solubility in water (6.05 g/100 ml at 25 °C) and dissolves 1.5 g/100 g (1.0 g/100 ml) water at 25 °C. This, coupled with its high volatility, makes it ideal for use as the non-polar solvent in liquid-liquid extraction. When used with an
Diethyl ether
10366530
to as "toilet water". In modern perfumery, the term eau de toilette is generally used to describe the concentration of fragrance, with eau de toilette being weaker than Eau de Parfum and stronger than Eau de Cologne. Eau de toilette is a weaker concentration of fragrance than pure perfume. The concentration of aromatic ingredients is typically as follows (ascending concentration): Perfume oils are often diluted with a solvent, though this is not always the case, and its necessity is disputed. By far the most common solvent for perfume oil dilution is ethanol or a mixture of ethanol and water. Perfume
Eau de toilette
1309190
different price range. Various chemicals may be used to increase the solvent power of water, such as the compounds in soaproot or yucca-root used by Native American tribes, or the ash lye (usually sodium hydroxide or potassium hydroxide) once widely used for soaking laundry in Europe. Soap, a compound made from lye and fat, is an ancient and common laundry aid. Modern washing machines typically use synthetic powdered or liquid laundry detergent in place of more traditional soap. Dry cleaning refers to any process which uses a chemical solvent other than water. The solvent used is typically tetrachloroethylene (perchloroethylene), which
Laundry
4989666
in the production of the solvents methyl isobutyl alcohol and methyl isobutyl ketone. These products arise via an initial aldol condensation to give diacetone alcohol. Condensation with acetylene gives 2-methylbut-3-yn-2-ol, precursor to synthetic terpenes and terpenoids. In the laboratory, acetone is used as a polar, aprotic solvent in a variety of organic reactions, such as S2 reactions. The use of acetone solvent is critical for the Jones oxidation. It does not form an azeotrope with water (see azeotrope (data)). It is a common solvent for rinsing laboratory glassware because of its low cost and volatility. Despite its common use as
Acetone
6469662
solvonium/solvate ions should be used, such as pCl in POCl. Inorganic nonaqueous solvent An inorganic nonaqueous solvent is a solvent other than water, that is not an organic compound. Common examples are liquid ammonia, liquid sulfur dioxide, sulfuryl chloride and sulfuryl chloride fluoride, phosphoryl chloride, dinitrogen tetroxide, antimony trichloride, bromine pentafluoride, hydrogen fluoride, pure sulfuric acid and other inorganic acids. These solvents are used in chemical research and industry for reactions that cannot occur in aqueous solutions or require a special environment. The reactions of the compounds containing xenon are mostly conducted in hydrogen fluoride or bromine pentafluoride, which dissolve
Inorganic nonaqueous solvent
10695269
solvent for the crystallization of lithium nitrite because the crystals can be extracted in a substantially pure state. The alcoholic solution will leave a white residue of small crystals upon evaporation. The addition of a small amount of water to this residue will yield the larger needle-shaped crystals of lithium nitrite monohydrate (LiNO·HO). The above methods will result in flat, needle-shaped crystals. These crystals are white and typically 1–2 cm. in length. Below 100 °C, these crystals will melt in their own water of crystallization and will tend to lose water slowly. Rapid dehydration will occur at temperatures above 160
Lithium nitrite
462249
developed countries. The use of water for transportation of materials through rivers and canals as well as the international shipping lanes is an important part of the world economy. Water is widely used in chemical reactions as a solvent or reactant and less commonly as a solute or catalyst. In inorganic reactions, water is a common solvent, dissolving many ionic compounds, as well as other polar compounds such as ammonia and compounds closely related to water. In organic reactions, it is not usually used as a reaction solvent, because it does not dissolve the reactants well and is amphoteric (acidic
Water
7756798
Solvent dye A solvent dye is a dye soluble in organic solvents. It is usually used as a solution in an organic solvent. Solvent dyes are used to color organic solvents, hydrocarbon fuels, waxes, lubricants, plastics, and other hydrocarbon-based nonpolar materials. Fuel dyes are one use of solvent dyes. Their molecules are typically nonpolar or little polar, and they do not undergo ionization. They are insoluble in water. They form a colloidal solution in solvents.They have poor (basic dyes) to good (metal complex based) light fastness. Solvent dyes are used for gold imitation (and other transparent metallic effects) of metallized
Solvent dye
6469654
Inorganic nonaqueous solvent An inorganic nonaqueous solvent is a solvent other than water, that is not an organic compound. Common examples are liquid ammonia, liquid sulfur dioxide, sulfuryl chloride and sulfuryl chloride fluoride, phosphoryl chloride, dinitrogen tetroxide, antimony trichloride, bromine pentafluoride, hydrogen fluoride, pure sulfuric acid and other inorganic acids. These solvents are used in chemical research and industry for reactions that cannot occur in aqueous solutions or require a special environment. The reactions of the compounds containing xenon are mostly conducted in hydrogen fluoride or bromine pentafluoride, which dissolve readily both xenon difluorides and its multiple derivatives, although sulfuric
Inorganic nonaqueous solvent
8750880
Nonaqueous titration Nonaqueous titration is the titration of substances dissolved in solvents other than water. It is the most common titrimetric procedure used in pharmacopoeial assays and serves a double purpose: it is suitable for the titration of very weak acids and very weak bases, and it provides a solvent in which organic compounds are soluble. The most commonly used procedure is the titration of organic bases with perchloric acid in "anhydrous" acetic acid. These assays sometimes take some perfecting in terms of being able to judge the endpoint precisely. The Karl Fischer titration for water content is another nonaqueous
Nonaqueous titration
8750892
per unit volume against volume of titrant is plotted, a differential curve is obtained in which the equivalence point is indicated by a peak. Nonaqueous titration Nonaqueous titration is the titration of substances dissolved in solvents other than water. It is the most common titrimetric procedure used in pharmacopoeial assays and serves a double purpose: it is suitable for the titration of very weak acids and very weak bases, and it provides a solvent in which organic compounds are soluble. The most commonly used procedure is the titration of organic bases with perchloric acid in "anhydrous" acetic acid. These assays
Nonaqueous titration
4255306
in a technique known as recrystallization. For biological molecules in which the solvent channels continue to be present to retain the three dimensional structure intact, microbatch crystallization under oil and vapor diffusion methods have been the common methods. Equipment for the main industrial processes for crystallization. The crystallization process appears to violate the second principle of thermodynamics. Whereas most processes that yield more orderly results are achieved by applying heat, crystals usually form at lower temperatures—especially by supercooling. However, due to the release of the heat of fusion during crystallization, the entropy of the universe increases, thus this principle remains
Crystallization
2831807
Fractional freezing Fractional freezing is a process used in process engineering and chemistry to separate substances with different melting points. It can be done by partial melting of a solid, for example in zone refining of silicon or metals, or by partial crystallization of a liquid, as in freeze distillation, also called normal freezing or progressive freezing. The initial sample is thus fractionated (separated into fractions). Partial crystallization can also be achieved by adding a dilute solvent to the mixture, and cooling and concentrating the mixture by evaporating the solvent, a process called solution crystallization. Fractional freezing is generally used
Fractional freezing
8852944
Crystallization adjutant A crystallization adjutant is a material used to promote crystallization, normally in a context where a material does not crystallize naturally from a pure solution. In macromolecular crystallography, the term additive is used instead of adjutant. An additive can either interact directly with the protein, and become incorporated at a fixed position in the resulting crystal or have a role within the disordered solvent, that in protein crystals constitute roughly 50% of the lattice volume. Polyethylene glycols of various molecular weights and high-ionic strength salts such as ammonium sulfate and sodium citrate that induce protein precipitation when used
Crystallization adjutant
9226285
Mother liquor A mother liquor is the part of a solution that is left over after crystallization. It is encountered chemical processes including sugar refining. It is the liquid obtained through crystal filtration. In crystallization, a solid (usually impure) is dissolved in a solvent at high temperature, taking advantage of the fact that most solids are more soluble at higher temperatures. As the solution cools, the solubility of the solute in the solvent will gradually become smaller. The resultant solution is described as supersaturated, meaning that there is more solute dissolved in the solution than would be predicted by its
Mother liquor
14606901
in the unstrained state undergo rapid crystallization upon stretching. Polymers can also be crystallized from a solution or upon evaporation of a solvent. This process depends on the degree of dilution: in dilute solutions, the molecular chains have no connection with each other and exist as a separate polymer coils in the solution. Increase in concentration which can occur via solvent evaporation, induces interaction between molecular chains and a possible crystallization as in the crystallization from the melt. Crystallization from solution may result in the highest degree of polymer crystallinity. For example, highly linear polyethylene can form platelet-like single crystals
Crystallization of polymers
3718309
Salting out Salting out (also known as salt-induced precipitation, salt fractionation, anti-solvent crystallization, precipitation crystallization, or drowning out) is an effect based on the electrolyte-non electrolyte interaction, in which the non-electrolyte could be less soluble at high salt concentrations. It is used as a method of purification for proteins, as well as preventing protein denaturation due to excessively diluted samples during experiments. The salt concentration needed for the protein to precipitate out of the solution differs from protein to protein. This process is also used to concentrate dilute solutions of proteins. Dialysis can be used to remove the salt if
Salting out
21004215
do have not been scaled up to meet climate mitigation goals. Absorption in the context of carbon capture refers to the use of a liquid solvent absorbing carbon dioxide from a gas. Amine solvents are most commonly used. This is currently the most common technology for carbon capture. Absorption is the most common method of direct air capture. A fan blows air into a filter that is lined with a liquid solvent absorbent. Currently, the most common sorbents are caustic solution and amine based solvents. Absorption with a caustic solvent is an acid-base reaction in which CO2 reacts with sodium
Direct air capture
8026297
little volatile oil to undergo expression, or their chemical components are too delicate and easily denatured by the high heat used in steam distillation. Instead, the oils are extracted using their solvent properties. Organic solvent extraction is the most common and most economically important technique for extracting aromatics in the modern perfume industry. Raw materials are submerged and agitated in a solvent that can dissolve the desired aromatic compounds. Commonly used solvents for "maceration/solvent extraction" include hexane, and dimethyl ether. In organic solvent extraction, aromatic compounds as well as other hydrophobic soluble substances such as wax and pigments are also
Fragrance extraction
18697590
proceeds according to the scheme: The equilibrium of the reaction is dependent on the concentrations of the reactants, the solvent and the temperature. The necessary quantity of urea for the formation of inclusion compounds varies from about 1 to 0.8 mole of urea per methyl- and methylene group in a carbon chain. The urea is added as a supersaturated aqueous solution to compensate for losses due to adduct formation during the process. In order to avoid a too high concentrations of adducts in the dewaxed oil a solvent such as methyl isobutyl ketone or methylene chloride is used for dilution.
Urea extraction crystallization
3718313
out in purification of proteins is that, in addition to precipitating a specific protein of interest, contaminants are also precipitated as well. Thus to obtain a purer protein of interest, additional purification methods such as ion exchange chromatography may be required. Salting out Salting out (also known as salt-induced precipitation, salt fractionation, anti-solvent crystallization, precipitation crystallization, or drowning out) is an effect based on the electrolyte-non electrolyte interaction, in which the non-electrolyte could be less soluble at high salt concentrations. It is used as a method of purification for proteins, as well as preventing protein denaturation due to excessively diluted
Salting out
16077878
are favored. Mineralizer The purpose of a mineralizer is to facilitate the transport of insoluble “nutrient” to a seed crystal by means of a reversible chemical reaction. Over time, the seed crystal accumulates the material that was once in the nutrient and grows. Mineralizers are additives that aid the solubilization of the nutrient solid. When used in small quantities, mineralizers function as catalysts. Typically, a more stable solid is crystallized from a solution that consists of a less stable solid and a solvent. The process is done by dissolution-precipitation or crystallization process. Hydrothermal growth involves the crystallization of a dissolved
Mineralizer
16077872
Mineralizer The purpose of a mineralizer is to facilitate the transport of insoluble “nutrient” to a seed crystal by means of a reversible chemical reaction. Over time, the seed crystal accumulates the material that was once in the nutrient and grows. Mineralizers are additives that aid the solubilization of the nutrient solid. When used in small quantities, mineralizers function as catalysts. Typically, a more stable solid is crystallized from a solution that consists of a less stable solid and a solvent. The process is done by dissolution-precipitation or crystallization process. Hydrothermal growth involves the crystallization of a dissolved solid at
Mineralizer
74973
changing. Specific industrial techniques to produce large single crystals (called "boules") include the Czochralski process and the Bridgman technique. Other less exotic methods of crystallization may be used, depending on the physical properties of the substance, including hydrothermal synthesis, sublimation, or simply solvent-based crystallization. Large single crystals can be created by geological processes. For example, selenite crystals in excess of 10 meters are found in the Cave of the Crystals in Naica, Mexico. For more details on geological crystal formation, see above. Crystals can also be formed by biological processes, see above. Conversely, some organisms have special techniques to "prevent"
Crystal
2247785
Tincture A tincture is typically an extract of plant or animal material dissolved in ethyl alcohol (ethanol). Solvent concentrations of 25–60% are common, but may run as high as 90%. In chemistry, a tincture is a solution that has ethanol as its solvent. In herbal medicine, alcoholic tinctures are made with various ethanol concentrations, 20% being the most common. Other solvents for producing tinctures include vinegar, glycerol (also called glycerine), diethyl ether and propylene glycol, not all of which can be used for internal consumption. Ethanol has the advantage of being an excellent solvent for both acidic and basic (alkaline)
Tincture
14606914
is opaque. Crystallinity also affects dyeing of polymers: crystalline polymers are more difficult to stain than amorphous ones because the dye molecules penetrate much easier through amorphous regions. Crystallization of polymers Crystallization of polymers is a process associated with partial alignment of their molecular chains. These chains fold together and form ordered regions called lamellae, which compose larger spheroidal structures named spherulites. Polymers can crystallize upon cooling from the melt, mechanical stretching or solvent evaporation. Crystallization affects optical, mechanical, thermal and chemical properties of the polymer. The degree of crystallinity is estimated by different analytical methods and it typically ranges
Crystallization of polymers
11404959
most common application of stratigraphic dating on volcanic rocks. In petrology the mineral clinopyroxene is used for temperature and pressure calculations of the magma that produced igneous rock containing this mineral. Clinopyroxene thermobarometry is one of several geothermobarometers. Two things make this method especially useful: first, clinopyroxene is a common phenocryst in igneous rocks easy to identify; and secondly, the crystallization of the jadeite component of clinopyroxene implies a growth in molar volume being thus a good indicator of pressure. Most contemporary ground breaking in igneous petrology has been published in prestigious American and British scientific journals of worldwide circulation
Igneous petrology
15146570
been known to take up to 6 months to prepare these materials. Cocrystals are typically generated through slow evaporation of solutions of the two components. This approach has been successful with molecules of complimentary hydrogen bonding properties, in which case cocrystallization is likely to be thermodynamically favored. Many other methods exist in order to produce cocrystals. Crystallizing with a molar excess of one cocrystal former may produce a cocrystal by a decrease in solubility of that one component. Another method to synthesize cocrystals is to conduct the crystallization in a slurry. As with any crystallization, solvent considerations are important. Changing
Cocrystal
4255298
Crystallization Crystallization is the (natural or artificial) process by which a solid forms, where the atoms or molecules are highly organized into a structure known as a crystal. Some of the ways by which crystals form are precipitating from a solution, freezing, or more rarely deposition directly from a gas. Attributes of the resulting crystal depend largely on factors such as temperature, air pressure, and in the case of liquid crystals, time of fluid evaporation. Crystallization occurs in two major steps. The first is nucleation, the appearance of a crystalline phase from either a supercooled liquid or a supersaturated solvent.
Crystallization
542228
filter paper into the receiving flask. Hot vapors from the boiling solvent keep the filter funnel warm, avoiding the premature crystallization. Like beakers, Erlenmeyer flasks are not normally suitable for accurate volumetric measurements. Their stamped volumes are approximate within about 5% accuracy. Erlenmeyer flasks are also used in microbiology for the preparation of microbial cultures. Erlenmeyer flasks used in cell culture are sterilized and may feature vented closures to enhance gas exchange during incubation and shaking. The use of minimal liquid volumes, typically no more than one fifth of the total flask volume, and baffles molded into the flask's internal
Erlenmeyer flask
14606893
Crystallization of polymers Crystallization of polymers is a process associated with partial alignment of their molecular chains. These chains fold together and form ordered regions called lamellae, which compose larger spheroidal structures named spherulites. Polymers can crystallize upon cooling from the melt, mechanical stretching or solvent evaporation. Crystallization affects optical, mechanical, thermal and chemical properties of the polymer. The degree of crystallinity is estimated by different analytical methods and it typically ranges between 10 and 80%, thus crystallized polymers are often called "semi-crystalline". The properties of semi-crystalline polymers are determined not only by the degree of crystallinity, but also by
Crystallization of polymers
14601494
is then suspended above the reservoir. Sitting-drop crystallization apparatus place the drop on a pedestal that is separated from the reservoir. Both of these methods require sealing of the environment so that equilibration between the drop and reservoir can occur. A microbatch usually involves immersing a very small volume of protein droplets in oil (as little as 1 µl). The reason that oil is required is because such low volume of protein solution is used and therefore evaporation must be inhibited to carry out the experiment aqueously. Although there are various oils that can be used, the two most common
Protein crystallization
4519679
provides for greater capacity for and requires less work to capture a given amount of CO. Piperazine's solubility is low, so it is often used in relatively small amounts to supplement another amine solvent. One or more of piperazine's performance advantages are often compromised in practice due to its low concentration; nonetheless, the CO absorption rate, heat of absorption, and solvent capacity are increased through the addition of piperazine to amine gas treating solvents, the most common of which is MDEA due to its unmatched high rate and capacity efficiency. For example, a 5 m PZ/5 m MDEA blend yields
Piperazine
2913093
Swern oxidation. Related to its ability to dissolve many salts, DMSO is a common ligand in coordination chemistry. Illustrative is the complex dichlorotetrakis(dimethyl sulfoxide)ruthenium(II) (RuCl(dmso)). In this complex, three DMSO ligands are bonded to ruthenium through sulfur. The fourth DMSO is bonded through oxygen. In general, the oxygen-bonded mode is more common. DMSO is a polar aprotic solvent and is less toxic than other members of this class, such as dimethylformamide, dimethylacetamide, "N"-methyl-2-pyrrolidone, and HMPA. DMSO is frequently used as a solvent for chemical reactions involving salts, most notably Finkelstein reactions and other nucleophilic substitutions. It is also extensively used
Dimethyl sulfoxide
11853343
elevated temperature, however usually not below room temperature. Almost any size or shape of a part can be cleaned. The most common cold solvent operation, this is usually used in small maintenance degreasers using a petroleum or mineral solvent. Usually to remove the bulk of the material, and prepare it for the cleaning tank. Although if the part does not need to be perfectly clean, then the operation can be ended after spraying. Spraying can also be used as a prequel other degreasing operations such as vapor degreasing which gives a better clean. The part is immersed in a tank
Solvent degreasing
7370064
its crystallization due to packing disruption; this results in a very low freezing point. Esters of 2-ethylhexanol are similarly affected and it therefore finds application as a feedstock in the production of plasticizers and lubricants, where its presence helps reduce viscosity and lower freezing points. Almost all 2-ethylhexanol manufactured is used as a precursor for the synthesis of the diester bis(2-ethylhexyl) phthalate (DEHP), a plasticizer. Because it is a fatty alcohol, its esters tend to have emollient properties. It is also commonly used as a low volatility solvent. 2-Ethylhexanol can also be used as an octane booster when reacted with
2-Ethylhexanol
14601490
using the salting in effect. The goal of crystallization is to produce a well-ordered crystal that is lacking in contaminants while still large enough to provide a diffraction pattern when exposed to X-rays. This diffraction pattern can then be analyzed to discern the protein’s tertiary structure. Protein crystallization is inherently difficult because of the fragile nature of protein crystals. Proteins have irregularly shaped surfaces, which results in the formation of large channels within any protein crystal. Therefore, the noncovalent bonds that hold together the lattice must often be formed through several layers of solvent molecules. In addition to overcoming the
Protein crystallization
4255320
in a jacket around the trough. Crystals precipitate on the cold surfaces of the screw/discs, from which they are removed by scrapers and settle on the bottom of the trough. The screw, if provided, pushes the slurry towards a discharge port. A common practice is to cool the solutions by flash evaporation: when a liquid at a given T temperature is transferred in a chamber at a pressure P such that the liquid saturation temperature T at P is lower than T, the liquid will release heat according to the temperature difference and a quantity of solvent, whose total latent
Crystallization
1586606
applications is commonly done by chemical extraction, using solvent extracts, which produces higher yields and is quicker and less expensive. The most common solvent is petroleum-derived hexane. This technique is used for most of the "newer" industrial oils such as soybean and corn oils. Supercritical carbon dioxide can be used as a non-toxic alternative to other solvents. Oils may be partially hydrogenated to produce various ingredient oils. Lightly hydrogenated oils have very similar physical characteristics to regular soy oil, but are more resistant to becoming rancid. Margarine oils need to be mostly solid at 32 °C (90 °F) so that
Vegetable oil
958826
Monsieur" and "Pour Monsieur Concentrée". As a rule of thumb, women's fragrances tend to have higher levels of aromatic compounds than men's fragrances. Fragrances marketed to men are typically sold as EdT or EdC, rarely as EdP or perfume extracts. Women's fragrances used to be common in all levels of concentration, but today are mainly seen in parfum, EdP and EdT concentrations. Perfume oils are often diluted with a solvent, though this is not always the case, and its necessity is disputed. By far the most common solvent for perfume is oil dilution is an alcohol solution, typically a mixture
Perfume
14545110
achieved by using a wool–rhodium complex as a chiral catalyst for hydrogenation of methyl furan. 2-Methyltetrahydrofuran is mainly used as a higher boiling substitute for tetrahydrofuran as a specialty solvent. It also is used in the electrolyte formulation for secondary lithium electrodes and as a component in alternative fuels. It is a valued solvent for low temperature reactions. 2-Methyltetrahydrofuran forms a glass, which does not crystallize, and is frequently used as a solvent for spectroscopic studies at −196 °C. Other common uses of 2-methyltetrahydrofuran is as a solvent for Grignard reagents used in organometallic and biphasic chemical processes, because of
2-Methyltetrahydrofuran
14575337
order of addition adjustments, and counterion adjustments can be made to optimize the one-pot process for a particular combination of carbonyl compound, nucleophile, and alkylating (or acylating) agent. Solvent adjustments between the two steps are common; if one solvent is used, tetrahydrofuran is the solvent of choice. Polar aprotic solvents should be avoided for the conjugate addition step. Concerning temperature, conjugate additions are usually carried out at low temperatures (-78 °C), while alkylations are carried out at slightly higher temperatures (0 to -30 °C). Less reactive alkylating agents may require room temperature. To 6.25 g (50 mmol) of 4,4-dimethyl-2-cyclohexen-1-one and
Vicinal difunctionalization
14601486
Protein crystallization Protein crystallization is the process of formation of a protein crystal. While some protein crystals have been observed in nature, protein crystallization is predominantly used for scientific or industrial purposes, most notably for study by X-ray crystallography. Like many other types of molecules, proteins can be prompted to form crystals when the solution in which they are dissolved becomes supersaturated. Under these conditions, individual protein molecules can pack in a repeating array, held together by noncovalent interactions. These crystals can then be used in structural biology to study the molecular structure of the protein, or for various industrial
Protein crystallization
8690422
sweat and solvent joinery. Since they are not "tapped" (threaded), they are simply called reducing bushings. A tee, the most common pipe fitting, is used to combine (or divide) fluid flow. It is available with female thread sockets, solvent-weld sockets or opposed solvent-weld sockets and a female-threaded side outlet. Tees can connect pipes of different diameters or change the direction of a pipe run, or both. Available in a variety of materials, sizes and finishes, they may also be used to transport two-fluid mixtures. Tees may be equal or unequal in size of their three connections, with equal tees the
Piping and plumbing fitting
14601502
to the difficulty inherent in crystallizing proteins. When the Protein Data Bank was founded in 1971, it contained only seven structures. Since then, the pace at which protein structures are being discovered has grown exponentially, with the PDB surpassing 20,000 structures in 2003, and containing over 100,000 as of 2014. Crystallization of proteins can also be useful in the formulation of proteins for pharmaceutical purposes. Protein crystallization Protein crystallization is the process of formation of a protein crystal. While some protein crystals have been observed in nature, protein crystallization is predominantly used for scientific or industrial purposes, most notably for
Protein crystallization
14751552
studied extensively. Aluminum-induced crystallization (AIC) and local laser crystallization are common in the literature, however not extensively used in industry. In both of these methods, amorphous silicon is grown using traditional techniques such as plasma-enhanced chemical vapor deposition (PECVD). The crystallization methods diverge during post-deposition processing. In aluminum-induced crystallization, a thin layer of aluminum (50 nm or less) is deposited by physical vapor deposition onto the surface of the amorphous silicon. This stack of material is then annealed at a relatively low temperature between 140 °C and 200 °C in a vacuum. The aluminum that diffuses into the amorphous silicon
Crystalline silicon
18697589
a large deviation from the straight-chain molecular structure, so that these compounds do not form urea adducts. This is used as part of the fatty acid analysis and for the separation or enrichment of specific fatty acids. For the separation of n-paraffins from other hydrocarbon compounds, urea is added with an approximately 20-fold molar excess. The urea crystallizes in a hexagonal crystal structure with about 5.5 to 5.8 Å wide channels. In these channels the n-paraffins are included. If the concentration of n-paraffins in the mixture is too high, the mixture is diluted with a solvent. In general, the reaction
Urea extraction crystallization
5194183
detectors used for size exclusion chromatography include online methods similar to the bench methods used above. By far the most common is the differential refractive index detector that measures the change in refractive index of the solvent. This detector is concentration-sensitive and very molecular-mass-insensitive, so it is ideal for a single-detector GPC system, as it allows the generation of mass v's molecular mass curves. Less common but more accurate and reliable is a molecular-mass-sensitive detector using multi-angle laser-light scattering - see Static Light Scattering. These detectors directly measure the molecular mass of the polymer and are most often used in
Molar mass distribution
15770959
a relatively large number of protons which are solvent-exchangeable, nucleic acid NMR is generally not done in DO solvent as is common with other types of NMR. This is because the deuterium in the solvent would replace the exchangeable protons and extinguish their signal. HO is used as a solvent, and other methods are used to eliminate the strong solvent signal, such as saturating the solvent signal before the normal pulse sequence ("presaturation"), which works best a low temperature to prevent exchange of the saturated solvent protons with the nucleic acid protons; or exciting only resonances of interest ("selective excitation"),
Nuclear magnetic resonance spectroscopy of nucleic acids
14606902
with a thickness on the order 10–20 nm when crystallized from a dilute solution. The crystal shape can be more complex for other polymers, including hollow pyramids, spirals and multilayer dendritic structures. A very different process is precipitation; it uses a solvent which dissolves individual monomers but not the resulting polymer. When a certain degree of polymerization is reached, the polymerized and partially crystallized product precipitates out of the solution. The rate of crystallization can be monitored by a technique which selectively probes the dissolved fraction, such as nuclear magnetic resonance. When polymers crystallize from an isotropic, bulk of melt
Crystallization of polymers
5270230
or alkali metals such as sodium or potassium. Other methods include the use of 4 Å molecular sieves, aluminium "tert"-butylate, calcium hydride (CaH), or fractional crystallization under inert atmosphere. "tert"-Butyl alcohol is used as a solvent, ethanol denaturant, paint remover ingredient, and gasoline octane booster and oxygenate. It is a chemical intermediate used to produce methyl "tert"-butyl ether (MTBE) and ethyl "tert"-butyl ether (ETBE) by reaction with methanol and ethanol, respectively, and "tert"-butyl hydroperoxide (TBHP) by reaction with hydrogen peroxide. As a tertiary alcohol, "tert"-butyl alcohol is more resistant to oxidation and less reactive than the other isomers of butanol.
Tert-Butyl alcohol
11985536
a single substance can have more than one acceptable name, like toluene, which may also be correctly named as "methylbenzene" or "phenylmethane". Some alternative names remain available as "retained names" for more general contexts. For example, tetrahydrofuran remains an unambiguous and acceptable name for the common organic solvent, even if the preferred IUPAC name is "oxolane". Substitutive nomenclature (replacement of hydrogen atoms in the parent structure) is used most extensively, for example "ethoxyethane" instead of diethyl ether and "tetrachloromethane" instead of carbon tetrachloride. Functional class nomenclature (also known as radicofunctional nomenclature) is used for acid anhydrides, esters, acyl halides and
Preferred IUPAC name
18280981
of solvent techniques and vapor deposition techniques, both of which have the potential to be scaled up with relative feasibility. In one-step solution processing, a lead halide and a methylammonium halide can be dissolved in a solvent and spin coated onto a substrate. Subsequent evaporation and convective self-assembly during spinning results in dense layers of well crystallized perovskite material, due to the strong ionic interactions within the material (The organic component also contributes to a lower crystallization temperature). However, simple spin-coating does not yield homogenous layers, instead requiring the addition of other chemicals such as GBL, DMSO, and toluene drips.
Perovskite solar cell
9083730
Diacetone alcohol Diacetone alcohol is a chemical compound with the formula CHC(O)CHC(OH)(CH), sometimes called DAA. This liquid is a common synthetic intermediate used for the preparation of other compounds, and is also used as a solvent. It occurs naturally in "Achnatherum robustum". First identified by Heintz, one standard laboratory preparation of DAA entails the Ba(OH)-catalyzed condensation of two molecules of acetone. It undergoes dehydration to give the α,β-unsaturated ketone, mesityl oxide: Hydrogenation of mesityl oxide gives the industrial solvent, methyl isobutyl ketone ("MIBK"). It is used in cellulose ester lacquers, particularly of the brushing type, where it produces brilliant gloss
Diacetone alcohol
267773
initiates crystallization centers. This is a common situation for the droplets of atmospheric clouds. Metastable phases are common in condensed matter. For example, diamond is a metastable form of carbon at standard temperature and pressure. It can be converted to graphite (plus leftover kinetic energy), but only after overcoming an activation energy – an intervening hill. Martensite is a metastable phase used to control the hardness of most steel. The bonds between the building blocks of polymers such as DNA, RNA, and proteins are also metastable. Adenosine triphosphate is a highly metastable molecule, colloquially described as being "full of energy"
Metastability
2962954
is initiated after a given crude drug formulation (typically prepared by solvent extraction of the natural material) is deemed "active" in a particular "in vitro" assay. If the end-goal of the work at hand is to identify which one(s) of the scores or hundreds of compounds are responsible for the observed "in vitro" activity, the path to that end is fairly straightforward: "In vitro" activity does not necessarily translate to activity in humans or other living systems. The most common means for fractionation are solvent-solvent partitioning and chromatographic techniques such as high-performance liquid chromatography (HPLC), medium-pressure liquid chromatography, "flash" chromatography,
Pharmacognosy
16296350
Radial chromatography Radial chromatography is a form of chromatography, a preparatory technique for separating chemical mixtures. It can also be referred to as Centrifugal Thin-Layer Chromatography. It is a common technique for isolating compounds and can be compared to column chromatography as a similar process. A common device used for this technique is a Chromatotron. Here the solvent travels from the center of the circular chromatography silica layered on a plate towards the periphery. The entire system is kept covered in order to prevent evaporation of solvent while developing a chromatogram. The wick at the center of system drips solvent
Radial chromatography
8167954
Fractional crystallization (geology) Fractional crystallization, or crystal fractionation, is one of the most important geochemical and physical processes operating within the Earth's crust and mantle. It is one of the main processes of magmatic differentiation. Fractional crystallization is the removal and segregation from a melt of mineral precipitates; except in special cases, removal of the crystals changes the composition of the magma. In essence, fractional crystallization is the removal of early formed crystals from an originally homogeneous magma (for example, by gravity settling) so that these crystals are prevented from further reaction with the residual melt. The composition of the
Fractional crystallization (geology)
8167959
to simulate natural processes accurately. Fractional crystallization (geology) Fractional crystallization, or crystal fractionation, is one of the most important geochemical and physical processes operating within the Earth's crust and mantle. It is one of the main processes of magmatic differentiation. Fractional crystallization is the removal and segregation from a melt of mineral precipitates; except in special cases, removal of the crystals changes the composition of the magma. In essence, fractional crystallization is the removal of early formed crystals from an originally homogeneous magma (for example, by gravity settling) so that these crystals are prevented from further reaction with the residual
Fractional crystallization (geology)
482761
of as its ability to reduce the solute's effective internal charge. Generally, the dielectric constant of a solvent is an acceptable predictor of the solvent's ability to dissolve common ionic compounds, such as salts. Dielectric constants are not the only measure of polarity. Because solvents are used by chemists to carry out chemical reactions or observe chemical and biological phenomena, more specific measures of polarity are required. Most of these measures are sensitive to chemical structure. The "Grunwald–Winstein mY scale" measures polarity in terms of solvent influence on buildup of positive charge of a solute during a chemical reaction. "Kosower's
Solvent
14601492
for crystallization, although high purity is neither necessary nor sufficient for crystallization. Solution pH can be very important and in extreme cases can result in different packing orientations. Buffers, such as Tris-HCl, are often necessary for the maintenance of a particular pH. Precipitants, such as ammonium sulfate or polyethylene glycol, are usually used to promote the formation of protein crystals. Vapor diffusion is the most commonly employed method of protein crystallization. In this method, a droplet containing purified protein, buffer, and precipitant are allowed to equilibrate with a larger reservoir containing similar buffers and precipitants in higher concentrations. Initially, the
Protein crystallization
3345660
of the low viscosities and high diffusivities associated with supercritical fluids. The extraction can be selective to some extent by controlling the density of the medium, and the extracted material is easily recovered by simply depressurizing, allowing the supercritical fluid to return to gas phase and evaporate leaving little or no solvent residues. Carbon dioxide is the most common supercritical solvent. It is used on a large scale for the decaffeination of green coffee beans, the extraction of hops for beer production, and the production of essential oils and pharmaceutical products from plants. A few laboratory test methods include the
Supercritical fluid
14606906
as polarized light microscopy and transmission electron microscopy. The methods used to determine the degree of crystallinity can be incorporated over time to measure the kinetics of crystallization. The most basic model for polymer crystallization kinetics comes from Hoffman nucleation theory. The crystallization process of polymers does not always obey simple chemical rate equations. Polymers can crystallize through a variety of different regimes and unlike simple molecules, the polymer crystal lamellae have two very different surfaces. The two most prominent theories in polymer crystallization kinetics are the Avrami equation and Lauritzen-Hoffman Growth Theory. Below their glass transition temperature, amorphous polymers
Crystallization of polymers
5552488
solvent-based crystallization. A different technology to create single crystalline materials is called epitaxy. As of 2009, this process is used to deposit very thin (micrometre to nanometer scale) layers of the same or different materials on the surface of an existing single crystal. Applications of this technique lie in the areas of semiconductor production, with potential uses in other nanotechnological fields and catalysis. Single crystal A single crystal or monocrystalline solid is a material in which the crystal lattice of the entire sample is continuous and unbroken to the edges of the sample, with no grain boundaries. The absence of
Single crystal
6440824
Sardinia and Ireland. It is by no means common, however, and usually occurs in only a small part of a granitic or dioritic mass, being sometimes restricted to an area of a few square yards. In most cases it is found near the center of the outcrop, though exceptionally it has been found quite close to the margin. It arises evidently from intermittent and repeated crystallization of the rock-forming minerals in successive stages. Such a process would be favored by complete rest, which would allow of supersaturation of the magma by one of the components. Rapid crystallization would follow, producing
Napoleonite
626344
non-crystallographic techniques. X-ray crystallography is one of the more efficient and important methods for attempting to decipher the three dimensional configuration of a folded protein. To be able to conduct X-ray crystallography, the protein under investigation must be located inside a crystal lattice. To place a protein inside a crystal lattice, one must have a suitable solvent for crystallization, obtain a pure protein at supersaturated levels in solution, and precipitate the crystals in solution. Once a protein is crystallized, x-ray beams can be concentrated through the crystal lattice which would diffract the beams or shoot them outwards in various directions.
Protein folding
1474159
These detergents emulsify hydrophobic soils and keep soil from redepositing on garments. Depending on the machine's design, either an anionic or a cationic detergent is used. The international GINETEX laundry symbol for dry cleaning is a circle. It may have the letter P inside it to indicate perchloroethylene solvent, or the letter F to indicate a flammable solvent (Feuergefährliches Schwerbenzin). A bar underneath the circle indicates that only mild cleaning processes is recommended. A crossed-out empty circle indicates that dry cleaning is not permitted. Perchloroethylene (PCE, or tetrachloroethylene) has been in use since the 1930s. PCE is the most common
Dry cleaning
8900604
bicyclic system. Each of the seminal reports of the Rubottom oxidation featured the peroxyacid meta-chloroperoxybenzoic acid (mCPBA) as the oxidant in dichloromethane (DCM), in the case of Hassner and Brook, and hexanes for Rubottom. While the reaction has been tweaked and modified since 1974, mCPBA is still commonly used as the oxidant with slightly more variation in the solvent choice. Today, DCM is the most common solvent followed by various hydrocarbon solvents including pentane and toluene. Notably, the reaction proceeds at relatively low temperatures and heating beyond room temperature is not necessary. Low temperatures allow the standard Rubottom oxidation conditions
Rubottom oxidation
4255322
evaporation. This process is insensitive to change in temperature (as long as hydration state remains unchanged). All considerations on control of crystallization parameters are the same as for the cooling models. Most industrial crystallizers are of the evaporative type, such as the very large sodium chloride and sucrose units, whose production accounts for more than 50% of the total world production of crystals. The most common type is the "forced circulation" (FC) model (see evaporator). A pumping device (a pump or an axial flow mixer) keeps the crystal slurry in homogeneous suspension throughout the tank, including the exchange surfaces; by
Crystallization
12191506
phenyl-C-butyric acid methyl ester (PCBM) devices where the PCBM tends to accumulate towards the device's bottom upon spin coating from ODCB solutions. This effect is seen because the more soluble component tends to migrate towards the “solvent rich” phase during the coating procedure, accumulating the more soluble component towards the film's bottom, where the solvent remains longer. The thickness of the generated film affects the phases segregation because the dynamics of crystallization and precipitation are different for more concentrated solutions or faster evaporation rates (needed to build thicker devices). Crystalline P3HT enrichment closer to the hole-collecting electrode can only be
Organic solar cell
7014958
assumed to be related to one another. A composition from which they could reasonably be produced by fractional crystallization is termed a "parental melt". To prove this, fractional crystallization models would be produced to test the hypothesis that they share a common parental melt. Fractional crystallization and accumulation of crystals formed during the differentiation process of a magmatic event are known as "cumulate rocks", and those parts are the first which crystallize out of the magma. Identifying whether a rock is a cumulate or not is crucial for understanding if it can be modelled back to a primary melt or
Igneous differentiation
3876787
Paint thinner A paint thinner is a solvent used to thin oil-based paints or clean up after their use. Commercially, solvents labeled "Paint Thinner" are usually mineral spirits having a flash point at about 40 °C (104 °F), the same as some popular brands of charcoal starter. Common solvents used as paint thinners include: Less common solvents used as paint thinner include: Exposure to vapors created by paint containing thinner or its clean up may be hazardous. The American Conference of Governmental Industrial Hygienists has established threshold limit values (TLVs) for most of these compounds. TLV is defined as the
Paint thinner
18565260
Industrial separation processes Industrial separation processes are technical procedures which are used in industry to separate a product from impurities or other products. The original mixture may either be a natural resource (like ore, oil or sugar cane) or the product of a chemical reaction (like a drug or an organic solvent). Separation processes are of great economic importance as they are accounting for 40 – 90% of capital and operating costs in industry. The separation processes of mixtures are including besides others washing, extraction, pressing, drying, clarification, evaporation, crystallization and filtration. Often several separation processes are performed successively. Separation
Industrial separation processes
7584980
often prepared by self-assembly, involving crystallization of a metal salt with a ligand. The mechanisms of crystal engineering and molecular self-assembly are relevant. The synthesis methods utilized to produce coordination polymers are generally the same methods used to grow any crystal. These generally include solvent layering (slow diffusion), slow evaporation, and slow cooling. (Because the main method of characterization of coordination polymers is X-ray crystallography, growing a crystal of sufficient size and quality is important.) Forces that determine metal-ligand complexes include van der Waals forces, pi-pi interactions, hydrogen bonding, and stabilization of pi bonds by polarized bonds in addition to
Coordination polymer
7216779
cause serious health damage. Chemical solvents also present an explosion hazard. A common choice of chemical solvent is hexane, which is widely used in the food industry and is relatively inexpensive. Benzene and ether can also separate oil. Benzene is classified as a carcinogen. Another method of chemical solvent extraction is Soxhlet extraction. In this method, oils from the algae are extracted through repeated washing, or percolation, with an organic solvent such as hexane or petroleum ether, under reflux in a special glassware. The value of this technique is that the solvent is reused for each cycle. Enzymatic extraction uses
Algaculture
14713525
either as its dihydrate or in the anhydrous form. Alternatively, it can be electrochemically generated from manganese(II) acetate. Stoichiometry is important to consider for these reactions, as two equivalents of oxidant are required if carbocation intermediates are desired (because Mn(OAc) is a one-electron oxidant). A second equivalent of manganese(III) acetate is also required if copper(II) acetate is used as a co-catalyst, because Mn(OAc) re-oxidizes Cu(I) to Cu(II). Glacial acetic acid is the most common solvent used, and although it results in heterogeneous reaction mixtures at room temperature, brief heating can be applied before the substrate is added to dissolve the
Manganese-mediated coupling reactions
4461141
a solvent with low evaporation rate. DMF is used in the production of acrylic fibers and plastics. It is also used as a solvent in peptide coupling for pharmaceuticals, in the development and production of pesticides, and in the manufacture of adhesives, synthetic leathers, fibers, films, and surface coatings. As a common and cheap reagent, DMF has many uses in the research laboratory Reactions including the use of sodium hydride in DMF as a solvent are somewhat hazardous; exothermic decompositions have been reported at temperatures as low as 26 °C. On a laboratory scale any thermal runaway is (usually) quickly
Dimethylformamide
19171680
its crystallization properties began to be studied in the 1970s. It was among the first reported examples of a protein whose tertiary structure contains two pseudo-symmetrical protein domains. Canavalin has since been used as a model system for studying protein crystallization, most notably in the study of protein crystal formation in space under microgravity conditions. Canavalin Canavalin is a plant protein found in the jack bean, sword bean, and related plants. It is the major storage protein found in these plants' seeds, and is one of four proteins readily isolated from the seeds; the others are concanavalin A, concanavalin B,
Canavalin
4255304
process examples include: Human time scale process examples include: Crystal formation can be divided into two types, where the first type of crystals are composed of a cation and anion, also known as a salt, such as sodium acetate. The second type of crystals are composed of uncharged species, for example menthol. Crystal formation can be achieved by various methods, such as: cooling, evaporation, addition of a second solvent to reduce the solubility of the solute (technique known as antisolvent or drown-out), solvent layering, sublimation, changing the cation or anion, as well as other methods. The formation of a supersaturated
Crystallization
13600934
recrystallization by measuring the melting point, since impurities lower the melting point. NMR spectroscopy can also be used to check the level of impurity. Repeated recrystallization results in some loss of material because of the non-zero solubility of compound A. The crystallization process requires an initiation step, such as the addition of a "seed" crystal. In the laboratory a minuscule fragment of glass, produced by scratching the side of the glass recrystallization vessel, may provide the nucleus on which crystals may grow. Successful recrystallization depends on finding the right solvent. This is usually a combination of prediction/experience and trial/error. The
Recrystallization (chemistry)
2978413
available. The choice of inlet type and injection technique depends on if the sample is in liquid, gas, adsorbed, or solid form, and on whether a solvent matrix is present that has to be vaporized. Dissolved samples can be introduced directly onto the column via a COC injector, if the conditions are well known; if a solvent matrix has to be vaporized and partially removed, a S/SL injector is used (most common injection technique); gaseous samples (e.g., air cylinders) are usually injected using a gas switching valve system; adsorbed samples (e.g., on adsorbent tubes) are introduced using either an external
Gas chromatography
18877709
Phase inversion (chemistry) Phase inversion is a chemical phenomenon exploited in the fabrication of artificial membranes. It is performed by removing the solvent from a liquid-polymer solution, leaving a porous, solid membrane. Phase inversion is a common method to form filtration membranes, which are typically formed using artificial polymers. The method of phase inversion is highly dependent on the type of polymer used and the solvent used to dissolve the polymer. Phase inversion can be carried out through one of four typical methods: The rate at which phase inversion occurs and the characteristics of the resulting membrane are dependent on
Phase inversion (chemistry)
18877711
small pore membranes such as nanofiltration and reverse osmosis. Phase inversion (chemistry) Phase inversion is a chemical phenomenon exploited in the fabrication of artificial membranes. It is performed by removing the solvent from a liquid-polymer solution, leaving a porous, solid membrane. Phase inversion is a common method to form filtration membranes, which are typically formed using artificial polymers. The method of phase inversion is highly dependent on the type of polymer used and the solvent used to dissolve the polymer. Phase inversion can be carried out through one of four typical methods: The rate at which phase inversion occurs and
Phase inversion (chemistry)
8690425
not common in plumbing. One cross fitting is more expensive than two tees. Caps, usually liquid- or gas-tight, cover the otherwise open end of a pipe. A cap attaches to the exterior of a pipe, and may have a solvent-weld socket end or a female-threaded interior. The exterior of an industrial cap may be round, square, rectangular, U- or I-shaped, or may have a handgrip. If a solvent-weld cap is used to provide for a future connection point, several inches of pipe must be left before the cap; when the cap is cut off for the future connection, enough pipe
Piping and plumbing fitting
5886734
process of washing a check is relatively simple and can be accomplished with basic solvents. The actual solvent is largely irrelevant — more importantly, the polarity of the solvent must match the polarity of the dye in the ink. For example, an ink that is mostly made of a polar dye would require a polar solvent (e.g. acetone or isopropanol). Both nail polish remover (acetone) and rubbing alcohol (isopropanol) are able to pull most common inks away from paper in minutes. Similarly, a non-polar dye would require a non-polar solvent (e.g. toluene or a similar hydrocarbon). Check washing Check washing
Check washing