Acetylation of glycerol catalyzed by different solid acids

Neste trabalho apresentamos os resultados da eterificação do glicerol com álcool benzílico, catalisada por diferentes sólidos ácidos. O mono-éter benzílico do glicerol foi o produto principal nas reações com a zeólita β e a resina ácida Amberlyst-35. Já o éter-di-benzílico foi o produto majoritário nas reações com o ácido p-tolueno-sulfônico e a argila K-10 como catalisadores. O ácido nióbico foi inativo na reação. A estrutura porosa da zeólita impediu a formação significativa de produtos de di e tri eterificação.In this work we present the results of glycerol etherification with benzyl alcohol, catalyzed by different solid acids. The mono-benzyl-glycerol ether was the main product in the reactions catalyzed by β zeolite and Amberlyst-35 acid resin, whereas di-benzyl-ether was formed in higher yield with the use of p-toluene-sulfonic acid and K-10 montmorillonite as catalyst. Niobic acid was inactive in this reaction. The porous structure of the zeolite impaired the formation of di and tri-benzyl-glycerol ethers.

Section: Resultsmentioning

confidence: 74%

Etherification of glycerol with benzyl alcohol catalyzed by solid acids

Silva¹,

Gonçalves²,

Lachter³

et al. 2009

“…Total glycerol consumption occurred within 2 h and the equilibrium, which consisted of a 55:45 di:triacetin ratio was reached within 9 h. In general, acid catalyzed transesterification reactions are slower than esterification reactions and perhaps this is the reason why acetins have been produced almost exclusively via glycerol esterification reactions with acetic acid and/or acetic anhydride using homogeneous and heterogeneous acid catalysts. 24,25,33 Recently, Mota et al 24 performed a very efficient glycerol acetylation via an esterification process employing a 4:1 acetic anhydride:glycerol ratio and different catalysts. Triacetin was produced with 100% selectivity and total glycerol conversion, at 60 o C, in 20 min, when zeolite Beta or K-10 Montmorillonite were used as catalysts.…”

Section: Resultsmentioning

confidence: 99%

“…In this context, the production of acetins is a chemically suitable application for the excess glycerol from biodiesel production. [20][21][22][23][24][25][26][27][28][29][30] Acetins are mono-, di-, and triacetate esters of glycerol. Monoacetins and diacetins have wide applications as raw materials for biodegradable polyesters, pharmaceuticals, food and cosmetic industries.…”

Section: Introductionmentioning

confidence: 99%

“…22,23 Conventionally, acetins are synthesized via glycerol esterification with excess acetic acid and/or acetic anhydride under mineral acid catalysis. 24 Currently, heterogeneous catalysts such as acidic ion-exchange organic resins, 20,21 zeolites, 25 niobic acid, 26 activated carbon-supported heteropolyacids, 27 zirconia-based catalysts, 28 metal/SBA-15 catalyst 29 among others are being utilized in the synthesis of acetins. Despite being widely used the acid catalyzed esterification process suffers from drawbacks such as high costs, corrosive/toxic reagents' use leading to environment problems and economical inefficiency.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Synthesis of bio-additives: transesterification of ethyl acetate with glycerol using homogeneous or heterogeneous acid catalysts

Meireles¹,

Pereira²

2013

Uma nova rota catalítica, de potencial interesse prático para a produção sustentável de acetinas a partir do glicerol, é descrita. Acetato de etila foi transesterificado com glicerol, numa razão glicerol: A new catalytic route with potential practical interest to sustainable production of bioadditives from glycerol is described. Ethyl acetate was transesterified with glycerol, in the ratio glycerol:EtOAc 1:10, at 25 or 90 o C using 0.1 equiv. of H 2 SO 4 or TsOH, as homogeneous catalysts. H 2 SO 4 led to the total glycerol consumption in 2 h. In the equilibrium, attained in 9 h, 100% yield of a diacetin:triacetin (55:45) mixture was formed. Using Amberlyst TM 15 dry and Amberlyst TM 16 wet in 1:30 glycerol:EtOAc ratio and reflux at 90 ºC the total glycerol consumption was achieved in 2 and 10h, respectively. The lower reactivity of Amberlyst-16 wet was explained in terms of deactivation of acid sites and decrease in glycerol diffusion to the inner resin pores, both factors caused by adsorbed water. The kinetics of glycerol transformation and product distribution in the equilibrium in relation to the H 2 SO 4 , Amberlyst-15 (dry) and Amberlyst-16 (wet) catalyzed reactions were measured.

“…It is necessary to find new applications for this product, [9][10][11] and value added to glycerin generated, otherwise this by-product could undermine the economic viability of any production process of biodiesel as renewable fuel. 5,7 The utilization of glycerol as a chemical platform represents an opportunity to obtain value added products from a highly functionalized and cheap raw material, and much research has been recently dedicated to find new chemical pathway for the glycerol transformation to value added products.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of polyesters from glycerol by-product of biodiesel production

Moura¹,

Nunes²,

Neto³

et al. 2012

resinas do tipo uréia/formaldeído ou fenol/formaldeído para melhorar as qualidades de aderência e resistência à umidade dessas resinas. Neste trabalho, foram sintetizados seis tipos de resinas derivadas do glicerol, sendo nomeadas GAA (glicerol/ácido adípico), GAAU (glicerol/ácido adípico/uréia), GAF (glicerol/ácido ftálico), GU (glicerol/uréia), GUF (glicerol/uréia/formaldeído) e GF (glicerol/formaldeído). As resinas derivadas dos ácidos carboxílicos tiveram melhor estabilidade térmica (até 350 ºC) do que as resinas derivadas do formaldeído (até 200 ºC). As massas moleculares médias das resinas foram determinadas por espectrometria de massas por tempo de vôo acoplada à ionização dessortiva de matriz por laser (MALDI-TOF MS) e cromatografia de permeação em gel (GPC), e encontram-se na faixa de 1800-2800 Da, sendo portanto, oligômeros, e os índices de polidispersão no intervalo de 1,3 a 1,8. As técnicas de ressonância magnética nuclear (NMR) de 1 H e 13 C foram usadas para identificar as estruturas das resinas.Glycerol, a by-product from biodiesel production can react with di-carboxylic organic acids, resulting in polyesters, and can be used in the composition of urea/formaldehyde or phenol/ formaldehyde resins to improve the qualities of adhesion and moisture resistance of them. In this work, six kinds of resins derived from glycerol, named as GAA (glycerol/adipic acid), GAAU (glycerol/adipic acid/urea), GAF (glycerol/phtalic acid), GU (glycerol/urea), GUF (glycerol/ urea/formaldehyde) and GF (glycerol/formaldehyde), were synthesized. The resins derived from carboxylic acids had better thermal stability (up to 350 ºC) than those derived from formaldehyde (up to 200 ºC). The average molecular weights of the resins were determined by matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and gelpermeation chromatography (GPC), and are in the range of 1800-2800 Da, being oligomers, and the polydispersity indexes are in the range of 1.3 to 1.8. The 1 H and 13 C nuclear magnetic resonance (NMR) techniques were used to identify the structure of the resins.