b ony lation ). ▁ ▁Other ▁carbon ate ▁est ers ▁may ▁subsequently ▁be ▁prepared ▁by ▁trans ester ification . ▁ ▁In ▁principle ▁carbon ate ▁est ers ▁can ▁be ▁prepared ▁by ▁direct ▁cond ens ation ▁of ▁m eth an ol ▁and ▁carbon ▁dio x ide . ▁ ▁The ▁reaction ▁is ▁however ▁therm od ynam ically ▁unf avor able . ▁A ▁select ive ▁memb rane ▁can ▁be ▁used ▁to ▁separate ▁the ▁water ▁from ▁the ▁reaction ▁mixture ▁and ▁increase ▁the ▁yield . ▁ ▁Ph os gen ation ▁ ▁Al co h ols ▁react ▁with ▁ph os g ene ▁to ▁yield ▁carbon ate ▁est ers ▁according ▁to ▁the ▁following ▁reaction : ▁▁ 2 ▁RO H ▁+ ▁CO Cl 2 ▁→ ▁RO ( CO ) OR ▁+ ▁ 2 ▁H Cl ▁ ▁Ph en ols ▁react ▁similarly . ▁ ▁Poly car bon ate ▁derived ▁from ▁bis phen ol ▁A ▁is ▁produced ▁in ▁this ▁manner . ▁This ▁process ▁is ▁high ▁yield ing . ▁However , ▁to xic ▁ph os g ene ▁is ▁used , ▁and ▁sto ichi ometric ▁quantities ▁of ▁base ▁( e . g . ▁py rid ine ) ▁are ▁required ▁to ▁neutral ize ▁the ▁hydro gen ▁ch lor ide ▁that ▁is ▁c og ener ated . ▁Ch lor o form ate ▁est ers ▁are ▁inter medi ates ▁in ▁this ▁process . ▁R ather ▁than ▁react ing ▁with ▁additional ▁alco hol , ▁they ▁may ▁dis pro port ion ate ▁to ▁give ▁the ▁desired ▁carbon ate ▁di esters ▁and ▁one ▁equivalent ▁of ▁ph os g ene : ▁▁ ▁Ph