Phase and chemical equilibria in the transesterification reaction of vegetable oils with supercritical lower alcohols

Anikeev, V. I.; Stepanov, D. A.; Ermakova, A.

doi:10.1134/s0036024411080024

Cited by 6 publications

(3 citation statements)

References 29 publications

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“…Previous work in the application of supercritical fluids to biodiesel production has been focused predominantly on the optimization of process variables and understanding the kinetics and phase equilibrium of oil transesterification in batch or flow reactors. ,− There have been a few investigations of chemical equilibria in the transesterification reaction using supercritical lower alcohols. ,− For instance, Anikeev , provided the thermodynamic data for all compounds participating in the transesterification reaction and constructed phase diagrams for these materials. Furthermore, Anikeev studied the chemical equilibria that occurred during the stepwise transesterification reactions between mixed triglycerides and methanol, thus leading to the prediction of the transesterification behavior of mixed triglycerides in the supercritical state.…”

Section: Introductionmentioning

confidence: 99%

Calculating the Thermodynamic Characteristics and Chemical Equilibrium of the Stepwise Transesterification of Triolein Using Supercritical Lower Alcohols

Zhang

Jin

et al. 2014

Ind. Eng. Chem. Res.

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A comparative study of triolein transesterification using three individual supercritical alcohols (methanol, ethanol, and isopropanol) was performed using thermodynamic analysis. The correlative properties were calculated for all components, including boiling point, critical parameters, acentric factor, enthalpy, entropy, and constant-pressure heat capacity. Chemical equilibria of the three reaction systems were discussed and diagrams of reaction enthalpy, Gibbs free energy and the chemical equilibrium constant as a function of temperature were constructed for the temperature range from 300 to 700 K. The results illustrated that, in the supercritical state, the triolein transesterification reaction proceeds primarily with methanol under the proper reaction conditions, but rarely occurs with ethanol or isopropanol. This observation was consistent with the experimental results reported in literature. This study provides a reliable method for analyzing analogous reaction systems for biodiesel synthesis with supercritical fluids.

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Section: Introductionmentioning

confidence: 99%

Calculating the Thermodynamic Characteristics and Chemical Equilibrium of the Stepwise Transesterification of Triolein Using Supercritical Lower Alcohols

Zhang

Jin

et al. 2014

Ind. Eng. Chem. Res.

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“…Several requirements must be met for the production of high quality biodiesel in homogeneous processes: (1) the yield of methyl esters of fatty acids must be no less than 96%; (2) the saponification product and toxic methanol must be thoroughly washed off; (3) the biodiesel must be "dried," since water leads to micro bial contamination and the formation of fatty acids that corrode metal parts (the biodiesel storage period does not exceed three months). The authors [5,6] also described homogeneous rapeseed oil interesterifica tion with no catalysts, but the process is performed in supercritical methanol (at a pressure of 12.4-28.6 MPa and a temperature of 310-340°C); a 98% degree of oil conversion apparently solves a range of environmental problems.…”

Section: Introductionmentioning

confidence: 97%

Heterogeneous biocatalytic processes of vegetable oil interesterification to biodiesel

et al. 2015

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The heterogeneous biocatalytic interesterification of vegetable oils to ethyl esters of fatty acids is studied. Interesterification with ethanol or ethyl acetate is performed using biocatalysts obtained by incorpo rating cell lysates of the rE. coli/lip recombinant strain that produces thermostable Thermomyces lanuginosus lipase, into silica xerogel. The interesterification of vegetable oils is performed in both a batch stirred tank reactor and a continuous reactor with a fixed bed of the prepared biocatalyst. It is shown that ethyl acetate is the best acylating reagent for the interesterification of vegetable oil triglycerides to ethyl esters of fatty acids. Unlike ethanol, ethyl acetate does not inactivate the biocatalyst irreversibly. Under the investigated condi tions, the biocatalyst's half inactivation time was 720 hours at 40°C.Keywords: heterogeneous biocatalysts, lysates of a recombinant strain producing thermostable lipase, incor poration into silica xerogel, interesterification of vegetable oils with ethyl acetate

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“…Existem alguns estados em que a água possui características completamente diferentes das usuais dentro das condições normais de temperatura e pressão. No estado supercrítico (T > 374 ºC e P > 220 bar), por exemplo, todas as propriedades do fluido sofrem alterações devidas à uma grande diminuição da sua densidade [99][100][101][102][103][104][105]. A constante dielétrica (ε) da água, que controla a solubilidade das espécies iônicas no meio, pode ser reduzida a valores entre 5 e 20 no estado supercrítico, contra o valor de 80 em condições normais [99].…”

Section: Considerações Gerais Introduçãounclassified

Alterações de propriedades da agua por processos fisicos e quimicos

Porto¹,

Faigle²

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Agradeço também à Natura, pela bolsa de pesquisa; a todos do laboratório de ensino, especialmente à Cláudia e ao Divino, pelas ajudas constantes e empréstimo de material; ao Prof. Ulf e alunos do laboratório Phoenix pela disponibilização de equipamentos; ao Prof. Pedro L.O. Volpe e ao Prof. José de Alencar Simoni pelas medidas calorimétricas; ao Claúdio B. Transferetti pelas ajudas nas medidas de refletância no infravermelho e outras; ao Marcelo Janini e Marta W. Donida pelo companheirismo e pela contribuição na correção da tese, e a todos aqueles que direta ou indiretamente ajudaram para a realização deste trabalho, mesmo não sendo citados nominalmente. Meu agradecimento especial ao Prof. Rogério Custódio que me orientou na parte de estudos teóricos. Pela sua atenção, disponibilidade e dedicação. Muito obrigada. O meu mais profundo respeito e gratidão ao meu orientador, Prof. Fernando Faigle, por resistir, insistir e concluir. Obrigada pela união da alquimia pessoal em um verdadeiro processo alquímico! Obrigada pela doação e pelo seu exemplo! v Dedico este trabalho a todos aqueles que buscam a verdade apesar do confronto inevitável com o poder, a ciência estabelecida e a cultura de sua época. O legado da verdade é o único seguro e irremediável, principalmente por nos fazer enfrentar a nós mesmos. Dentre os poucos que tive o privilégio de conhecer dedico-o particularmente à Lucia, por me fazer chegar até aqui. vi CURRICULUM VITAE MARIA EUGÊNIA GARCIA PORTO

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Phase and chemical equilibria in the transesterification reaction of vegetable oils with supercritical lower alcohols

Cited by 6 publications

References 29 publications

Calculating the Thermodynamic Characteristics and Chemical Equilibrium of the Stepwise Transesterification of Triolein Using Supercritical Lower Alcohols

Calculating the Thermodynamic Characteristics and Chemical Equilibrium of the Stepwise Transesterification of Triolein Using Supercritical Lower Alcohols

Heterogeneous biocatalytic processes of vegetable oil interesterification to biodiesel

Alterações de propriedades da agua por processos fisicos e quimicos

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