Methyl Lactate Yield Research Articles

Catalytic conversion of glycerol to value-added chemicals in alcohol

With the aim to directly use the mixture of glycerol and methanol from the biodiesel production for value-added chemical production, catalytic conversion of refined glycerol to lactic acid (LA) and propylene glycol (PG) using mixed solid catalysts of CaO and CuO in methanol medium was first investigated. At the optimum condition, the yields of LA and PG achieved were 46mol% and 35mol%, respectively. For recycling the catalysts, a combined process of glycerol conversion to alkyl lactate was further investigated. Using this integrated process, 45mol% methyl lactate yield and 28mol% PG yield were achieved in methanol medium, and 45mol% ethyl lactate and 18mol% PG yield were achieved in ethanol medium. The test for crude glycerol conversion showed that the impurities had slightly negative effects on glycerol conversion and product yield in methanol medium but no obvious effect in ethanol medium. Similar glycerol conversion and product yield were obtained when the mixture of glycerol, methanol, and CaO from biodiesel production were directly used as starting material. This result suggests that the mixture from biodiesel production can be directly used to produce valued-added chemicals such as methyl lactate and PG.

Ferric chloride as an efficient and reusable catalyst for methanolysis of poly(lactic acid) waste

Ferric chloride (FeCl3) was used to catalyze the methanolysis of poly(lactic acid) (PLA) to recover methyl lactate. The effects of experimental parameters such as reaction temperature, reaction time, amount of FeCl3 and dosage of methanol on results were studied in detail. The results showed that under the optimized reaction conditions of n(methanol):n(PLA) = 5:1, n(FeCl3):n(PLA) = 0.01:1, 130 °C and 4.0 h, the conversion of PLA reached 96.0 % and the yield of methyl lactate was up to 87.2 %. FeCl3 could be repeatedly used at least 6 times without significant decrease in the conversion of PLA and yield of methyl lactate under the given conditions. The kinetics of the reaction was also investigated. The results indicated that the methanolysis of PLA catalyzed by FeCl3 was a first-order kinetic reaction with activation energy of 32.41 kJ/mol.

Tin‐containing Silicates: Alkali Salts Improve Methyl Lactate Yield from Sugars

This study focuses on increasing the selectivity to methyl lactate from sugars using stannosilicates as heterogeneous catalyst. All group I ions are found to have a promoting effect on the resulting methyl lactate yield. Besides, the alkali ions can be added both during the preparation of the catalyst or directly to the solvent mixture to achieve the highest reported yield of methyl lactate (ca. 75 %) from sucrose at 170 °C in methanol. The beneficial effect of adding alkali to the reaction media applies not only to highly defect-free Sn-Beta prepared through the fluoride route, but also to materials prepared by post-treatment of dealuminated commercial Beta zeolites, as well as ordered mesoporous stannosilicates, in this case Sn-MCM-41 and Sn-SBA-15. These findings open the door to the possibility of using other preparation methods or different Sn-containing silicates with equally high methyl lactate yields as Sn-Beta.

Methanolysis of poly(lactic acid) using acidic functionalized ionic liquids as catalysts

ABSTRACTThe methanolysis of poly(lactic acid) (PLA) was studied by using acidic ionic liquids (ILs) as catalyst in detail. The results showed that HSO3‐functionalized ILs exhibited higher catalytic activity than non‐functionalized ILs and traditional acid catalyst such as H2SO4. The influences of experimental parameters, such as the amount of catalyst, reaction temperature, methanolysis time, and dosages of methanol on the conversion of PLA, yield of methyl lactate were investigated. Under the optimal conditions, using 1‐methyl‐3‐(3‐sulfopropyl)‐immidazolium hydrogen sulfate ([HSO3‐pmim][HSO4]) as catalyst, the IL could be reused up to six times without apparent decrease in the conversion of PLA and yield of methyl lactate. The kinetics of the reaction was also investigated. The results indicated that the methanolysis of PLA in [HSO3‐pmim][HSO4] was a first‐order kinetic reaction with activation energy of 47.01 kJ/mol and Arrhenius constant of 2.7 × 107 min−1. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40817.

A facile and efficient method to improve the selectivity of methyl lactate in the chemocatalytic conversion of glucose catalyzed by homogeneous Lewis acid

A facile and efficient method to improve the selectivity of methyl lactate (MLA) in the chemical conversion of glucose in methanol catalyzed by homogeneous Lewis acid was established. The yield of MLA was efficiently improved through controlling the acidity of the reaction solution by neutralization of protons generated from the hydrolysis/methanolysis of SnCl4. The mechanism of glucose conversion to MLA catalyzed by SnCl4-NaOH was explored. The effects of the concentration of catalyst and substrate and the reaction temperature and time were systematically studied. The catalyst system of SnCl4-NaOH can efficiently convert glucose, fructose, and sucrose to MLA with yields of 47%, 57%, and 51% at 160°C for 2.5 h, respectively. The catalyst can be regenerated and reused at least three times in the conversion of glucose to MLA without significant loss of activity and selectivity.

Methanolysis of poly(lactic acid) (PLA) catalyzed by ionic liquids

Abstract Poly(lactic acid) (PLA) was depolymerized by methanol in the presence of a novel catalyst: ionic liquids. It was found that the purification method of the main products in the methanolysis catalyzed by ionic liquids was simpler than that of traditional compounds, such as sulfuric acid. Qualitative analysis indicated that the main product in the methanolysis process was methyl lactate. The influences of experimental parameters, such as the amount of ionic liquids, methanolysis time, reaction temperature, and dosages of methanol on the conversion of PLA, yield of methyl lactate were investigated. Under the optimum conditions, using ionic liquid 1-butyl-3-methylimidazolium acetate ([Bmim][Ac]) as catalyst, results showed that the ionic liquid could be reused up to 6 times without apparent decrease in the conversion of PLA and yield of methyl lactate. The kinetics of the reaction was also investigated. The results indicated that the methanolysis of PLA was a first-order kinetic reaction with activation energy of 38.29 kJ/mol. In addition, a possible catalysis mechanism of the methanolysis of PLA was proposed.

Conversion of biomass-derived carbohydrates to methyl lactate using solid base catalysts

A study of the liquid-phase conversion of biomass-derived sugars directly to methyl lactate catalyzed over solid base catalysts is presented. The yield of methyl lactate reached 29.45% under optimal reaction conditions. The effects of reaction time, reaction temperature, and catalysts calcination temperature were investigated. Fresh and used catalysts were characterized by XRD, CO2-TPD, and N2-adsorption techniques. MgO with the highest concentration of weakly basic sites was found to show the highest catalytic activity for the conversion of sugars to methyl lactate.

Conversion of triose sugars with alcohols to alkyl lactates catalyzed by Brønsted acid tin ion-exchanged montmorillonite

We describe the Brønsted acid catalysis of tin ion-exchanged montmorillonite (Sn-Mont), which is easily prepared by the ion-exchange of naturally occurring sodium montmorillonite (Na-Mont) with an aqueous tin tetrachloride solution, for the conversion of two trioses, i.e., dihydroxyacetone (DHA) and glyceraldehyde (GLA), in alcohols to afford the corresponding alkyl lactates. For the conversion of DHA with methanol, the product distribution closely depends on the substrate concentrations, reaction temperatures, and reaction times. Under the optimized reaction conditions, an almost quantitative yield of methyl lactate is obtained with the production of water as the exclusive side-product. Additionally, the montmorillonite catalyst is easily recovered from the reaction mixture by filtration, and reused without any loss in activity. Sn-Mont also demonstrates a high activity for the conversion of DHA with higher alcohols, such as EtOH, nPrOH, and nBuOH, to the corresponding alkyl lactates in 89–93% yields.