Highly Selective, High-Speed Hydrolysis-Free O-acylation induced with subcritical water in the absence of catalyst.
Sustainable process-product development & green chemistry
Green Organic Synthesis Routes (T1-2)
Keywords: organic synthesis, O-acylation, subcritical water, hydrolysis-free, catalyst-free
Masahiro Sato, Hajime Kawanami, Toshirou Yokoyama and Yutaka Ikushima*
*National Institute of Advanced Industrial Science and Technology (AIST) , Research Center for Compact Chemical Process, Nigatake 4-2-1, Miyagino-ku, Sendai 983-8551, Japan
E-mail: y-ikushima@aist.go.jp, masahiro-satou@aist.go.jp
Keiichirou Matsushima
Hokkaido Industrial Research Institute, Department of Environmental Process Engineering, N19-W11, Kita-ku , Sapporo 060-0819, Japan
We have developed a high-speed, highly selective and hydrolysis-free acylation of various monohydroxy compounds such as primary and secondary alcohols and phenols by anhydride even in the absence of catalyst with the use of a flow-type of subcritical water (subH2O) microreaction system, in which the desired ester products are obtained in excellent yields >93% and quantitative selectivities at temperatures of 200 to 250°C and at constant pressure of 5MPa. Tertiary alcohols can be successfully transformed into the corresponding esters by using a large excess amount of anhydride at lower temperatures below 200°C. By controlling the equivalent molar acetic anhydride to alcohols, moreover, the subH2O microreaction system makes possible to regioselectively acylate any hydroxyl groups of various dihydroxyl compounds. This system nicely demonstrates the potential benefits resulting from the combination of subH2O properties and microprocess in advanced progress of acylation. Finally, it seems worth noting that this approach induced by subH2O microreaction system is environmentally benign process that is applied in commercial industrial acylation, thus making this approach of general interest for “green” organic synthesis.
Presented Tuesday 18, 15:20 to 15:40, in session Green Organic Synthesis Routes (T1-2).
