Acid-catalyzed oligomerization of glycerol investigated by electrospray ionization mass spectrometry

Medeiros, Miguel A.; Araújo, Maria Helena; Augusti, Rodinei; Oliveira, Luiz C.A.; Lago, Rochel M.

doi:10.1590/s0103-50532009000900015

Cited by 39 publications

(29 citation statements)

References 33 publications

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“…Besides linear diglycerol, cyclic dimers, C 6 H 12 O 4 , can be formed by further condensation [23,24], or even acyclic side products like ketones, aldehydes or diols of the same molecular composition C 6 H 12 O 4 as identified by Medeiros et al [25] who performed the oligomerization of glycerol with H 2 SO 4 in homogeneous phase (Fig. 3).…”

Section: Diglycerol Basicsmentioning

confidence: 94%

Oligomerization of glycerol – a critical review

Martin

Richter

2010

Euro J Lipid Sci & Tech

153

127

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The oligomerization of glycerol to preferentially di-and triglycerol is reviewed, with primary focus on the use of heterogeneous acidic and basic catalysts. Low molecular-weight oligomers have found a wide field of applications in cosmetics, food industry and polymer production. The growing market intensified research work on the selective catalytic oligomerization of glycerol. Performing the reaction of glycerol in the presence of microporous and mesoporous solid catalysts aims at exerting shape-selective effects on the reaction, suppressing the abundant formation of cyclic isomers and cutting further polymerization of the target products. Enhanced selectivity to diglycerol is observed over some type of catalysts, but the solids suffer from leaching of active alkaline cations from the solid, severe deterioration of crystallinity of zeolites and even dissolution of the solids in the hot glycerol during batch reaction at temperatures in the range of 240-2608C. In those cases it is difficult to separate homogeneous and heterogenous reaction routes, and the shape-selective effects are levelled off. The oligomerization is a consecutive reaction, and complete conversion of glycerol favours formation of high molecular-weight glycerol oligo-and polymers. To achieve maximum yield of diglycerol, the reaction has to be interrupted at glycerol conversions of ca. 50%. Alternative reaction engineering is required to overcome the inherent disadvantages of a batch reaction. Examples will be given for a selective glycerol oligomerization under reduced pressure in a so-called fall-film reactor using super-acidic polymers as catalysts.

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Section: Diglycerol Basicsmentioning

confidence: 94%

Oligomerization of glycerol – a critical review

Martin

Richter

2010

Euro J Lipid Sci & Tech

153

127

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“…Vários trabalhos [27,[29][30][31][32][33][34][35][36] descrevem a polimerização do glicerol para obter oligômeros (Figura 2), (1 ≤ n ≤ 18), utilizando catalisadores homogêneos e heterogêneos. Nesses trabalhos, são apresentadas moléculas de cadeia curta e simples (di, tri, tetra, penta e hexaglicerol) como produto.…”

Section: Introductionunclassified

Influência da temperatura e da natureza do catalisador na polimerização do glicerol

Medeiros¹,

Rezende²,

Araújo³

et al. 2010

Polímeros

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Resumo: Neste trabalho, a polimerização do glicerol na presença de catalisador ácido (H 2 SO 4 ou H 3 PO 4 ) e básico (NaOH), para produzir resinas termofixas foi investigada. Os resultados mostraram que as variáveis como a temperatura de reação, o tipo e a concentração do catalisador são críticas para a obtenção de bons rendimentos e seletividade para materiais poliméricos. Em condições otimizadas, i.e. H 2 SO 4 como catalisador, 140 °C por 24 horas, foi possível obter polímeros com 98% de seletividade. Após polimerização, os materiais obtidos foram submetidos a extrações com diferentes solventes, i.e. água, THF e hexano. Os extratos foram caracterizados por ESI(+)-MS e por espectroscopia na região do infravermelho, que permitiram verificar a presença de oligômeros de até seis unidades monoméricas. Para menores tempos de reação, e.g. 4 horas, foi possível obter elevada seletividade (100%) para oligômeros, mas com baixa conversão de glicerol (25%). Além disso, verificou-se que os outros catalisadores (H 3 PO 4 e NaOH) apresentam baixa atividade para promover a polimerização do glicerol, e.g. rendimento de 25% após 24 horas. Palavras-chave: Glicerol, polimerização, resina termofixa, poliglicerol. Influence of Temperature and Nature of the Catalyst on Glycerol PolymerizationAbstract: In this work, an investigation was made of the glycerol polymerization in the presence of acid (H 2 SO 4 or H 3 PO 4 ) and base (NaOH) catalysts to produce thermosetting resins. The results showed that the reaction temperature and catalyst concentration are critical to obtain good yield and selectivity. Under optimum condition, i.e. H2SO4 catalyst, 140 °C for 24 hours it was possible to obtain polymers with 98% selectivity. After the polymerization the materials were submitted to extractions with different solvents, i.e. water, THF and hexane. The extracts were characterized by ESI(+)-MS (Electro-Spray Ionization Mass Spectrometry) and by FTIR, showing the presence of short-chain oligomers (up to six units). For shorter reaction times, e.g. 4 hours, it was possible to obtain high selectivity (100%) for oligomers, but with low glycerol conversion (25%). It was also observed that the other catalysts (H 3 PO 4 and NaOH) showed low activity to promote glycerol polymerization, e.g. yields of 25% after 24 hours. Keywords: Glycerol, polymerization, thermosetting resin, polyglycerol. IntroduçãoA crescente produção de biodiesel, através da transesterificação [1][2][3] de óleos vegetais ou gorduras animais (Figura 1), em todo o mundo [4] e em especial no Brasil, deve levar a um aumento significativo do volume de glicerol no mercado. Para cada tonelada de triglicerídeos processada, são produzidos pelo menos 100 kg de glicerol [4][5][6] . Como consequência, o preço do glicerol cai fortemente no mercado em todo o mundo [7] . Essa queda de preço é uma tendência mundial, não sendo diferente no Brasil, que em 2005 registrou preços de glicerol em torno de R$ 3000 t -1 , mas já em 2007, a mesma quantidade de glicerol era comercializada por R$ 1700 t -1...

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“…As stated by Huang et al 20 and Schlaf et al, 24 the alcohol and aldehyde can be easily condensed over acid catalysts in the hydrogenolysis of glycerol; da Silva et al 25 and Medeiros et al 26 have demonstrated that the condensation reaction between the glycerol and assorted alcohols, and the self-condensation of glycerol can be readily achieved over acid catalyst. Based on these proposed mechanism of formation, as shown in Scheme 4, in the present of TsOH, these identified byproducts can be supposed from the following reactions: (i) the decomposition of TPD to produce glycerol, and followed by the subsequent hydrogenolysis reaction, (ii) the condensation of 1,3-PD and acetaldehyde, and (iii) the self-condensation of glycerol or 1,2-PD.…”

Section: Reaction Scheme and Product Identificationmentioning

confidence: 91%

Hydrogenolysis of 2-tosyloxy-1,3-propanediol into 1,3-propanediol over Raney Ni catalyst

Zheng¹,

Wang²,

Zhang³

et al. 2013

J. Braz. Chem. Soc.

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2-Tosiloxi-1,3-propanodiol (TPD), um potencial precursor para produção de 1,3-propanodiol (1,3-PD), é produzido através da tosilação do glicerol com a ajuda de uma técnica de proteção de grupos. Neste trabalho, discutiu-se a hidrogenólise do TPD em 1,3-PD sobre catalisador de Raney Ni através de diferentes parâmetros de reação para otimizar as condições de reação para formação seletiva do 1,3-PD. O mecanismo de hidrogenólise do TPD e reações laterais também foram confirmados pela técnica de cromatografia em fase gasosa acoplada à espectrometria de massas (GC-MS).2-Tosyloxy-1,3-propanediol (TPD), a potential precursor for 1,3-propanediol (1,3-PD) production, is produced by the tosylation of glycerol with the help of protecting group techniques. In this work, the hydrogenolysis of TPD into 1,3-PD over Raney Ni catalyst is discussed at different reaction parameters to optimize the reaction conditions for selective formation of 1,3-PD. The mechanisms of the hydrogenolysis of TPD and the side reactions were also confirmed by gas chromatography-mass spectrometry (GC-MS) technique.

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Acid-catalyzed oligomerization of glycerol investigated by electrospray ionization mass spectrometry

Cited by 39 publications

References 33 publications

Oligomerization of glycerol – a critical review

Oligomerization of glycerol – a critical review

Influência da temperatura e da natureza do catalisador na polimerização do glicerol

Hydrogenolysis of 2-tosyloxy-1,3-propanediol into 1,3-propanediol over Raney Ni catalyst

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