6163-76-4Relevant articles and documents
Microwave-assisted ionic liquid-catalyzed selective monoesterification of alkylphosphonic acids—an experimental and a theoretical study
Harsági, Nikoletta,Henyecz, Réka,ábrányi-Balogh, Péter,Drahos, László,Keglevich, Gy?rgy
, (2021/09/07)
It is well-known that the P-acids including phosphonic acids resist undergoing direct es-terification. However, it was found that a series of alkylphoshonic acids could be involved in mo-noesterification with C2–C4 alcohols under microwave (MW) irradiation in the presence of [bmim][BF4] as an additive. The selectivity amounted to 80–98%, while the isolated yields fell in the range of 61–79%. The method developed is a green method for P-acid esterification. DFT calculations at the M062X/6–311+G (d,p) level of theory (performed considering the solvent effect of the corresponding alcohol) explored the three-step mechanism, and justified a higher enthalpy of activation (160.6–194.1 kJ·mol–1) that may be overcome only by MW irradiation. The major role of the [bmim][BF4] additive is to increase the absorption of MW energy. The specific chemical role of the [BF4] anion of the ionic liquid in an alternative mechanism was also raised by the computations.
An efficient method for the esterification of phosphonic and phosphoric acids using silica chloride
Sathe, Manisha,Gupta, Arvind K.,Kaushik
, p. 3107 - 3109 (2007/10/03)
Silica chloride is used as an effective heterogeneous catalyst for the rapid esterification of alkyl/aryl phosphonic/phosphoric acids to their corresponding alkyl/aryl phosphonates/phosphates under mild conditions with quantitative yields.
