Direct ester condensation from a 1:1 mixture of carboxylic acids and alcohols catalyzed by hafnium(IV) or zirconium(IV) salts

Ishihara, Kazuaki; Nakayama, Masaya; Ohara, Suguru; Yamamoto, Hisashi

doi:10.1016/s0040-4020(02)00966-3

Cited by 186 publications

(77 citation statements)

References 56 publications

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“…In polycondensation is preferred catalyzed systems (ISHIHARA et al, 2002;LIGABUE et al, 1998;TAKASU et al, 2003). The most common methods for polyesterification use strong Bronsted or Lewis acid catalysts, usually using large excess of either carboxylic acid or alcohol monomer in order to achieve high reaction yields (OLAH et al, 1978).…”

Section: Introductionmentioning

confidence: 99%

Synthesis of carboxylate complexes and evaluation of their catalytic activities for polyesterification of castor oil (Ricinum communis) with terephthalic acid

2015

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ABSTRACT. The use of castor oil (Ricinus communis) has been pointed out as an interesting alternative to produce several polymers obtained from step-growth polymerization and are suitable to be used as resins and coatings. The new polymeric materials did not show homogeneity in their chains, as indicated by their high polydispersity. Indeed, the polydispersity index value varied from 5.49 for the polymer produced in the presence of the nickel complex to 12.42 for these prepared with the cobalt compound. On the other hand, the final material presented high molecular weight, being the lower value (M w = 13400 Da) observed for the polymer prepared with the nickel complex and the highest (M w = 36400 Da) verified for the one obtained with the cobalt compound. It was observed only a glass transition temperature for all the materials, suggesting an amorphous structure of polymeric chains.Keywords: polyester, step-growth polymerization, ricinoleate metal complexes, homogeneous Catalysis.Síntese de complexos de carboxilatos e avaliação da atividade catalítica para poliesterificação de óleo de mamona (Ricinum communis) com ácido tereftálico RESUMO. O uso de óleo de mamona (Ricinus communis) tem sido apontado como uma alternativa interessante para a produção de vários polímeros via polimerização em massa e são adequados para serem utilizados como resinas e revestimentos. , para polímeros produzidos a partir de complexos de níquel, até 12,42 para polímeros produzidos com complexo de cobalto. Por outro lado, o material produzido apresenta alto peso molecular médio, sendo o menor valor (M w = 13.400 Da) para materiais produzidos com complexo de níquel e maior valor (M w = 36.400 Da) para materiais obtidos com complexos de cobalto. Observou-se apenas uma transição vítrea para todos os materiais produzidos, sugerindo estrutura amorfa para os polímeros produzidos.Palavras-chave: poliéster, polimerização em massa, complexos metálicos de ricinoleato, catálise homogênea.

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Section: Introductionmentioning

confidence: 99%

Synthesis of carboxylate complexes and evaluation of their catalytic activities for polyesterification of castor oil (Ricinum communis) with terephthalic acid

2015

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“…Various catalysts developed for acylation with acyl halides include use of bases like pyridine and Et3N [4][5], DMAP [6], and Bu3P [7]. Acylation with acids [8,9], acyl imidazoles [10], and acyl urea [11], are also known. Acid catalyzed acylation mainly requires polymeric acids [12,13]; and metal chlorides [14][15][16], metal triflates such as Sc(OTf)3/Bi(OTf)3/Li(OTf)3 [17][18][19], metal perchlorates (LiClO4 /BiOClO4) [20,21] have also been utilized as Lewis acid catalysts for acylation of alcohols.…”

Section: Introductionmentioning

confidence: 99%

Zinc dust: An extremely active and reusable catalyst in acylation of phenols, thiophenol, amines and alcohols in a solvent-free system

2010

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“…In Box 1, a detailed protocol for this reaction is reported. Esterification with 1,2-diols proceeded well to give the corresponding diesters in high yields, while Lewis acidic metal salts were not suitable for use with these diols owing to tight chelation with metal ions 13 . For example, the condensation between cis-1,2-cyclohexanediol and 4-phenylbutyric acid with 4 gave the corresponding diester in 90% yield, while no esterification product was obtained by heating a mixture of 1,2-butanediol and 1-adamantanecarboxylic acid in toluene in the presence of HfCl 4 .…”

Section: Introductionmentioning

confidence: 99%

Direct ester condensation catalyzed by bulky diarylammonium pentafluorobenzenesulfonates

2007

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A protocol for ester condensation between equimolar amounts of carboxylic acids and alcohols catalyzed by bulky diarylammonium pentafluorobenzenesulfonate is described. We also present procedures for the synthesis of N-(2,6-diisopropylphenyl)-Nmesitylammonium pentafluorobenzenesulfonate. The present ester condensation proceeds well under mild conditions even without the removal of generated water. The synthesis of N-(2,6-diisopropylphenyl)-N-mesitylammonium pentafluorobenzenesulfonate will take B5 days. The ester condensation reactions will take B6 h to 3 days. INTRODUCTIONThe ester condensation reaction is among the most fundamental organic transformations, and more environmentally benign alternative synthetic approaches to the ones currently used are in strong demand by the chemical industry 1 . Conventionally, the ester condensation reaction of carboxylic acids with alcohols is catalyzed by Brønsted acids such as HCl, H 2 SO 4 , p-toluenesulfonic acid and so on for acid-resistance substrates. For acid-sensitive substrates, weak Brønsted acids such as pyridinium p-toluenesulfonate should be used. However, these have lower catalytic activities and the reactants that can be used are rather limited. With regard to green chemistry, in particular with respect to atom economy and E-factor, several catalytic methods for the ester condensation reaction between equimolar amounts of carboxylic acids and alcohols have been developed [2][3][4][5][6] . Conventionally, in fact, esterifications are conducted with an excess of carboxylic acids or alcohols against its reaction counterpart in the presence of an acid catalyst, or with a stoichiometric dehydrating reagent or activated carboxylic acid derivative in the presence of a stoichiometric amount of base. The use of excess amounts of substrates is a wasteful practice in itself. Furthermore, the use of stoichiometric dehydrating reagents or activated carboxylic acid derivatives leads to the formation of significant amounts of undesired by-products. Purifying the crude products from (excess) substrates or from reaction by-products is a rather demanding task-also in financial termsrequiring additional apparati and additional amounts of materials, energy (e.g., for azeotropic reflux) and time. It is therefore evident why the direct catalytic condensation between equimolar amounts of carboxylic acids and alcohols that does not require the presence of dehydrating agents is, at least in principle, such an attractive synthetic goal. Among these 'green' catalytic condensations, metalfree organocatalytic methods are particularly desirable, especially for industrial processes. [OTf] À is the salt of a superacid (trifluoromethansulfonic acid (TfOH)) and a weak base (Ph 2 NH), it is a strong Brønsted acid, and as such is difficult to use in the reaction of sterically demanding and acid-sensitive alcohols.In the course of our continuing study on environmentally benign dehydration catalysts, we have developed N,N-dimesitylammo-

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Direct ester condensation from a 1:1 mixture of carboxylic acids and alcohols catalyzed by hafnium(IV) or zirconium(IV) salts

Cited by 186 publications

References 56 publications

<b>Synthesis of carboxylate complexes and evaluation of their catalytic activities for polyesterification of castor oil (<i>Ricinum communis</i>) with terephthalic acid

<b>Synthesis of carboxylate complexes and evaluation of their catalytic activities for polyesterification of castor oil (<i>Ricinum communis</i>) with terephthalic acid

Zinc dust: An extremely active and reusable catalyst in acylation of phenols, thiophenol, amines and alcohols in a solvent-free system

Direct ester condensation catalyzed by bulky diarylammonium pentafluorobenzenesulfonates

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