594-61-6Relevant articles and documents
A simple synthetic route for the preparation of tetramethylglycolide from lactic acid
Watanabe, Kohtaro,Andou, Yoshito,Shirai, Yoshihito,Nishida, Haruo
, p. 159 - 161 (2013)
Poly(tetramethylglycolide), a chemical recyclable polymer, is currently attracting a lot of interest as a substitute for poly(Llactic acid). We report here a simple and convenient route for the synthesis of tetramethylglycolide (TMG) from lactic acid. This method involves three steps: (1) one-step protection of lactic acid by cyclic acetalization employing acetone; (2) -methylation of the obtained 2,2,5-trimethyl-1,3-dioxolan-4-one; and (3) one-pot synthesis of TMG including the hydrolysis of 2,2,5,5-tetramethyl- 1,3-dioxolan-4-one. We found significant advantages of the incorporation of existing reactions in the synthesis of TMG.
Synthesis of bio-based methacrylic acid from biomass-derived itaconic acid over barium hexa-aluminate catalyst by selective decarboxylation reaction
Bohre, Ashish,Novak, Uro?,Grilc, Miha,Likozar, Bla?
, (2019/07/31)
An environmentally-benign, efficient and inexpensive high-surface-area barium hexa-aluminate (BaAl12O19, BHA) was developed as a catalyst for the decarboxylation of the biomass-derived itaconic acid (IA) to bio-based methacrylic acid (MAA). A maximal 50% final yield of MAA with a high product selectivity was obtained under relatively mild synthesis reaction conditions (250 °C; 20 bar N2). The reported selective MAA production was elevated, operating process characteristics were significantly less harsh, and no depleting critical raw materials were utilized when paralleled to the procedures with alkaline mineral bases, noble metal-containing heterogeneous catalysis systems and unrenewable feed resources (e.g. isobutene), applied previously. It was found that the doping of palladium on BHA support (Pd@BHA) did not improve MAA productivity. The effect of the time (25–300 min), temperature (175–275 °C), pressure (10–40 bar), reacting substrate concentration (0.10–0.19 mol L–1), metallic oxide mass (0.5–3.0 g) and type on IA conversion, MAA content MAA content and rates was determined, examining also recyclability. BHA catalyst was characterized with various structural techniques, such as energy-dispersive X-ray spectroscopy (EDS), X-ray powder diffraction (XRD), CO2 temperature-programmed desorption (TPD), scanning electron microscopy (SEM) and N2 physisorption.
METHOD FOR THE PRODUCTION OF METHYLSUCCINIC ACID AND THE ANHYDRIDE THEREOF FROM CITRIC ACID
-
Page/Page column 14, (2018/04/21)
A process for the preparation of methylsuccinic acid in any form, including its salts, its mono- and diester derivatives and the anhydride thereof, which comprises reacting citric acid or a derivative thereof in decarboxylation conditions, said process comprising (i) reacting citric acid or mono- and diester derivatives thereof in a non- aqueous solvent, specifically excluding alcohols, on a metallic catalyst at a temperature between 50 to 400°C and under a partial hydrogen pressure from 0.1 to 50 bar or (ii) reacting citric acid or any salt thereof or mono-, di- and triester derivatives thereof on a metallic catalyst in solvents comprising at least 5% water, at a temperature of from 50 to 400°C under a hydrogen partial pressure from 0.1 to 400 bar
Photocatalytic hydrogenation coupling of acetone into pinacol using formic acid as hydrogen source
Cao, Bao Y.,Xu, Shan,Ren, You L.,Yu, Yan,Guo, Jin Y.,Zhang, Li,Li, Na,Zhang, Guo C.,Zhou, Chun S.
, p. 1773 - 1776 (2017/11/23)
We demonstrated photocatalytic hydrogenation coupling of acetone into 2,3-dimethyl-2,3-butanediol with formic acid as a hydrogen source. In this synergetic system, the conversion of acetone and formic acid was dramatically increased than that in the individual reaction system. Consequently, the selectivity of 2,3-dimethyl-2,3-butanediol was relatively high over that of NaTaO3 and Na2Ti3O7 photocatalysts. Additionally, in this acetoneformic acid reaction system, the presence of acetone can effectively restrain the generation of CO during the decomposition of formic acid.
Flow-Assisted Synthesis: A Key Fragment of SR 142948A
Kitching, Matthew O.,Dixon, Olivia E.,Baumann, Marcus,Baxendale, Ian R.
, p. 6540 - 6553 (2017/09/13)
We report a series of multi-step flow operations to deliver an advanced hydrazine intermediate used in the assembly of the neurotensin modulator SR 142948A. Several new reactor configurations have enabled chemical transformations that would be otherwise difficult or dangerous to perform at scale. Overall the flow approach has allowed the preparation of kilogram quantities of the required hydrazine through a short and efficient route.
Highly selective one-step dehydration, decarboxylation and hydrogenation of citric acid to methylsuccinic acid
Verduyckt, Jasper,De Vos, Dirk E.
, p. 2616 - 2620 (2017/04/06)
The one-step dehydration, decarboxylation and hydrogenation of the bio-based and widely available citric acid is presented. This reaction sequence yields methylsuccinic acid with yields of up to 89%. Optimal balances between the reaction rates of the different steps were found by varying the hydrogenation catalyst and the reaction parameters (H2 pressure, pH, temperature, time and catalyst-to-substrate ratio).
FeOOH and derived phases: Efficient heterogeneous catalysts for clofibric acid degradation by advanced oxidation processes (AOPs)
Sable, Shailesh S.,Ghute, Pallavi P.,álvarez, Pedro,Beltrán, Fernando J.,Medina, Francesc,Contreras, Sandra
, p. 46 - 54 (2015/02/19)
In this study the degradation of an aqueous solution of clofibric acid was investigated during catalytic ozonation and Fenton-like process with FeOOH - derived catalysts. From the different calcination temperatures tested, it has been observed that the most active catalyst is the commercial FeOOH calcined at 200°C, when maghemite and hematite are the predominant phases obtained. The best result, at room temperature, for CFA mineralization was observed over 0.5 wt% Pd on FeOOH (calcined at 200°C) among all tested catalysts, achieving 68% and 81% mineralization degree, in 2 h and 6 h, respectively, in catalytic ozonation and 66% and 71% of mineralization degree within 2 h and 6 h, respectively for Fenton process. The efficiency of the Fenton-like process is enhanced at higher temperature (40-60°C), reaching a mineralization degree up to 82% in 6 h. Furthermore, Pd impregnation on FeOOH increased the catalyst stability.
A PROCESS FOR THE PRODUCTION OF METHACRYLIC ACID AND ITS DERIVATIVES AND POLYMERS PRODUCED THEREFROM
-
Page/Page column 26, (2013/11/18)
A process for the production of methacrylic acid by the base catalysed decarboxylation of at least one dicarboxylic acid selected from itaconic, citraconic or mesaconic acid or mixtures thereof is described. The decarboxylation is carried out at a temperature in the range from 100 to 199°C. A method of preparing polymers or copolymers of methacrylic acid or methacrylic acid esters is also described.
Response surface methodology for oxidative degradation of the basic yellow 28 dye by temperature and ferrous ion activated persulfate
G?zmen, Belgin,S?nmez, ?zgür,Turabik, Meral
, p. 6831 - 6839 (2013/07/26)
The decomposition of the persulfate by Fe2+ ions results in the production of oxidative sulfate radical anions. In present study, the oxidative degradation of the basic yellow 28 dye solution was studied by using persulfate and ferrous ions. To
THERMAL SALT SPLITTING OF AMMONIUM CARBOXYLATES
-
Page/Page column 4, (2011/06/10)
The present invention relates to a process for preparing hydroxycarboxylic acids, preferably α- and β-hydroxycarboxylic acids, from ammonium carboxylates of the general formula in which R1, R2 and R3 are each independently H, OH, (C1-C6)-alkyl optionally substituted by a hydroxyl group, (C1-C6)-alkenyl optionally substituted by a hydroxyl group, (C1-C6)-alkoxy optionally substituted by a hydroxyl group, (C1-C6) -alkylthio-(C1-C6)-alkyl optionally substituted by a hydroxyl group, (C6-C10)-aryl optionally substituted by a hydroxyl group, (C7-C12)-aralkyl optionally substituted by a hydroxyl group, (C3-C5)-heteroaryl optionally substituted by a hydroxyl group, with the proviso that at least one hydroxyl group is present in at least one R1, R2 and R3 radical, preferably R1═H, CH3, CH2CH3, C6H5, (CH2)2SCH3 and R2═H, CH3 and R3═OH, equally preferably R1═CH2OH, CHOHCH3 and R2═R3═H, CH3, more preferably R1═R2═CH3 and R3═OH, equally more preferably R1═CH2OH, R2═CH3 and R3═H, comprising the following step: heating an aqueous starting solution comprising the ammonium carboxylate to form, by thermal decomposition of the ammonium carboxylate, the hydroxycarboxylic acid and ammonia, and simultaneously to remove at least a portion of the free water and of the ammonia formed from the solution and thus to obtain a product fraction comprising the hydroxycarboxylic acid, characterized in that the content of the ammonium salt in the starting solution is less than 60% by weight, the thermal decomposition of the ammonium salt and the removal of the free water and of the ammonia formed are effected in one process step, the conversion of the ammonium salt being more than 20 mol %, preferably more than 30 mol %, more preferably more than 50 mol %, especially preferably more than 75 mol %, very especially preferably more than 90 mol % and especially more than 95 mol %, and no ether, alcohol or hydrocarbon is used as an entraining agent.
