Graphite Oxide-Catalyzed Esterification and Transesterification

Abstract

Graphite oxide (GO) was involved in the esterification of carboxylic acids with alcohols or phenols and the transesterification of esters with alcohols. Three types of GO prepared by different methods were screened and GO by modified Hummers method was found superior to the others. The esterification of primary and secondary alcohols afforded the corresponding esters in moderate to excellent yields under mild conditions. GO-catalyzed esterification of tertiary alcohols and phenols took place hardly. Moreover, GO showed highly catalytic activity for the transesterification. As a weakly acidic solid catalyst, GO is easily available, cheap, environmentally benign, and well tolerant to various functional groups. Only catalyzed by GO, the esterification of long-chain carboxylic acids and the transesterification of the glycerol ester of long-chain carboxylic acids underwent steadily. As such, GO-catalyzed esterification and transesterification could be used in the biodiesel preparation potentially.

Regenerable Acidity of Graphene Oxide in Promoting Multicomponent Organic Synthesis

“…Graphene oxide (GO), a 2D, carbonaceous material bearing different oxygen functional groups such as alcohol, epoxide, ketones, and carboxylic acid 9–12 , is emerging as a green alternative for organic transformations and particularly superb in acidic carbocatalysis 5,13,14 . The inherent Brønsted acidity of GO, due to the presence of acidic oxygen groups on the edge of GO sheets, has been well exploited in the synthesis of benzylpyrazolyl coumarins 15 , thioacetals 16 , ethers 17 , and other Brønsted acid-catalyzed reactions such as transamidation 18 , Fisher esterification 19–22 , Boc-protection of alcohols 23 , and Kabachnik-Fields reactions 24 . Despite these extensive studies, only the Brønsted acidic nature of GO was recognized.…”

Synthesis of a molecularly defined single-active site heterogeneous catalyst for selective oxidation of N-heterocycles

“…Carbon catalysts have been widely applied in the selective oxidation of alkanes 9 – 13 , alcohols 14 – 18 , amines 19 – 22 , thiols and sulfides 5 , 23 , the nucleophilic addition of alcohol to an epoxide 24 , aldehyde acetalization or esterification 24 , 25 , Michael addition reactions 26 , 27 , F-C addition of indoles to α,β-unsaturated ketones 28 and the synthesis of dipyrromethane 29 , the catalytic reduction of olefin 30 , 31 and nitrobenzene 32 , C-heteroatom coupling reactions 7 , 33 , 34 and heterocycles dehydrogenative aromatization 35 – 37 , etc.…”

Carbon-catalysed reductive hydrogen atom transfer reactions

“…These reactions encompass the oxidative hydrogen atom transfer reactions. In addition, the O-rich carbon materials have been active catalysts in various reactions (that is, nucleophilic addition of alcohol to an epoxide 22 , aldehyde acetalization or esterification 23,24 , Michael addition reactions 25,26 , F-C addition of indoles to a,bunsaturated ketones 27 and synthesis of dipyrromethane 28 , among others 29,30 ). In these studies, nearly all of the organic transformations have been focused on oxidative hydrogen atom transfer reactions or acid-catalysed reactions with heteroatommodified carbon materials (Fig.…”