R3P (sometimes called phosphanes) such as triphenylphosphine, Ph3P. Triphenylphosphine is produced industrially by the reaction between phosphorus trichlorid, chlorobenzene, and sodium: , where Ph = Under controlled conditions or especially with bulky R groups, similar reactions afford less substituted derivatives such as chlorodiisopropylphosphine. Conversion of alcohols to alkyl chlorides Phosphorus trichloride is commonly used to convert primary and secondary alcohols to the corresponding chlorides. As discussed above, the reaction of alcohols with phosphorus trichloride is sensitive to conditions. The mechanism for the ROH →RCl conversion involves the reaction of HCl with phosphite esters: . The first step proceeds with nearly ideal stereochemistry but the final step far less so owing to an SN2 pathway. Redox reactions Phosphorus trichloride undergoes a variety of redox reactions: PCl3 as a nucleophile Phosphorus trichloride has a lone pair, and therefore can act as a Lewis base, e.g., forming a 1:1 adduct Br3B-PCl3. Metal complexes such as Ni(PCl3)4 are known, again demonstrating the ligand properties of PCl3. This Lewis basicity is exploited in the Kinnear–Perren reaction to prepare alkylphosphonyl dichlorides (RP(O)Cl2) and alkylphosphonate esters (RP(O)(OR')2). Alkylation of phosphorus trichloride is effected in the presence of aluminium trichloride give the alkyltrichlorophosphonium salts, which are versatile intermediates: PCl3 + RCl + AlCl3 → RPCl + AlCl The RPCl product can then be decomposed with water to produce an alkylphosphonic dichloride RP(=O)Cl2. PCl3 as a ligand PCl3, like the more popular phosphorus trifluoride, is a ligand in coordination chemistry. One example is Mo(CO)5PCl3. Uses PCl3 is important indirectly as a precursor to PCl5, POCl3 and PSCl3, which are used in many applications, including herbicides, insecticides, plasticisers, oil additives, and flame retardants. For example, oxidation of PCl3 gives POCl3, which is used for the manufacture of triphenyl phosphate and tricresyl phosphate, which find application as flame retardants and plasticisers for PVC. They are also used to make insecticides such as diazinon. Phosphonates include the herbicide glyphosate. PCl3 is the precursor to triphenylphosphine for the Wittig reaction, and phosphite esters which may be used as industrial intermediates, or used in the Horner-Wadsworth-Emmons reaction, both important methods for making alkenes. It can be used to make trioctylphosphine oxide (TOPO), used as an extraction agent, although TOPO is usually made via the corresponding phosphine. PCl3 is also used directly as a reagent in organic synthesis. It is used to convert primary and secondary alcohols into alkyl chlorides, or carboxylic acids into acyl