- A simple synthetic route for the preparation of tetramethylglycolide from lactic acid
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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.
- Watanabe, Kohtaro,Andou, Yoshito,Shirai, Yoshihito,Nishida, Haruo
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Read Online
- Synthesis of bio-based methacrylic acid from biomass-derived itaconic acid over barium hexa-aluminate catalyst by selective decarboxylation reaction
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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.
- Bohre, Ashish,Novak, Uro?,Grilc, Miha,Likozar, Bla?
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- METHOD FOR THE PRODUCTION OF METHYLSUCCINIC ACID AND THE ANHYDRIDE THEREOF FROM CITRIC ACID
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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
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Page/Page column 14
(2018/04/21)
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- Photocatalytic hydrogenation coupling of acetone into pinacol using formic acid as hydrogen source
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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.
- Cao, Bao Y.,Xu, Shan,Ren, You L.,Yu, Yan,Guo, Jin Y.,Zhang, Li,Li, Na,Zhang, Guo C.,Zhou, Chun S.
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p. 1773 - 1776
(2017/11/23)
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- Flow-Assisted Synthesis: A Key Fragment of SR 142948A
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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.
- Kitching, Matthew O.,Dixon, Olivia E.,Baumann, Marcus,Baxendale, Ian R.
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p. 6540 - 6553
(2017/09/13)
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- Highly selective one-step dehydration, decarboxylation and hydrogenation of citric acid to methylsuccinic acid
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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).
- Verduyckt, Jasper,De Vos, Dirk E.
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p. 2616 - 2620
(2017/04/06)
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- FeOOH and derived phases: Efficient heterogeneous catalysts for clofibric acid degradation by advanced oxidation processes (AOPs)
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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.
- Sable, Shailesh S.,Ghute, Pallavi P.,álvarez, Pedro,Beltrán, Fernando J.,Medina, Francesc,Contreras, Sandra
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- A PROCESS FOR THE PRODUCTION OF METHACRYLIC ACID AND ITS DERIVATIVES AND POLYMERS PRODUCED THEREFROM
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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.
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Page/Page column 26
(2013/11/18)
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- Response surface methodology for oxidative degradation of the basic yellow 28 dye by temperature and ferrous ion activated persulfate
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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
- G?zmen, Belgin,S?nmez, ?zgür,Turabik, Meral
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p. 6831 - 6839
(2013/07/26)
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- THERMAL SALT SPLITTING OF AMMONIUM CARBOXYLATES
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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.
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Page/Page column 4
(2011/06/10)
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- Reactive Extraction of Free Organic Acids from the Ammonium Salts Thereof
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The invention relates to a process for converting ammonium salts of organic acids to the particular free organic acid, wherein an aqueous solution of the ammonium salt is contacted with an organic extractant and the salt is dissociated at temperatures and pressures at which the aqueous solution and the extractant are in the liquid state, and a stripping medium or entraining gas is introduced in order to remove NH3 from the aqueous solution and transfer at least a portion of the free organic acid formed to the organic extractant. The invention described here thus provides an improved process for releasing an organic acid, preferably a carboxylic, sulphonic or phosphonic acid, especially an alpha-hydroxycarboxylic acid or beta-hydroxycarboxylic acid, from the ammonium salt thereof by release and removal of ammonia and simultaneous extraction of the acid released with a suitable extractant from the aqueous phase. This process corresponds to a reactive extraction. The reactive extraction of an organic acid from the aqueous ammonium salt solution thereof can be improved significantly by the use of a stripping medium or entraining gas, for example nitrogen, air, steam or inert gases, for example argon. The ammonia released is removed from the aqueous solution by the continuous gas stream and can be fed back into a production process. The free acid can be obtained from the extractant by a process such as distillation, rectification, crystallization, re-extraction, chromatography, adsorption, or by a membrane process.
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Page/Page column 11
(2010/08/22)
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- Racemization-free monomer: A-hydroxyisobutyric acid from bio-based lactic acid
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In order to solve the important problem of the racemization of poly(L-lactic acid), a high yield of racemization-free monomer: a-hydroxyisobutyric acid (HIBA) was synthesized from biobased lactic acid by methylation using specific bases with bulky side groups. Obtained HIBA can be converted into poly(tetramethylglycolide), which is racemization-free and has higher melting and glass transition points than poly(L-lactic acid).
- Watanabe, Kohtaro,Andou, Yoshito,Shirai, Yosihito,Nishida, Haruo
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supporting information; experimental part
p. 698 - 699
(2011/01/11)
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- METHODS FOR PRODUCING ALKYL(METH)ACRYLATES
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The invention relates to methods for producing alkyl(meth)acrylates, comprising the following steps: transesterifying an a-hydroxy carboxylic acid alkyl ester with (meth)acrylic acid whereby obtaining alkyl(meth)acrylates and a-hydroxy carboxylic acid, and; dehydrating the a-hydroxy carboxylic acid whereby obtaining (meth)acrylic acid.
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Page/Page column 33; 35-36
(2008/06/13)
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- TRANSESTERIFICATION METHODS
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The invention relates to transesterification methods, comprising the steps of A) mixing an organic acid a) with an ester b) and B) transferring the alcohol group of the ester b) to the acid a) in order to obtain the ester of the acid a) and the acid of the ester b), whereby the step B) is carried out in a distilling apparatus.
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Page/Page column 33; 35-36
(2008/06/13)
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- METHOD FOR PRODUCING ALPHA-HYDROXYCARBOXYLIC ACIDS AND THE ESTERS THEREOF
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The invention relates to a method for the selective, economical production of methacrylic acid and methacrylic esters on the basis of acetone cyanhydrin. According to the inventive method, 2-hydroxy-2-methylpropionic acid is produced by reacting acetone cyanhydrin with sulfuric acid in the presence of water and a suitable polar solvent, and is isolated. The 2-hydroxy-2-methylpropionic acid so produced is used to produce methacrylic acid by β elimination of water.
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Page/Page column 34-36
(2008/06/13)
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- Method for producing 2-hydroxyisobutyric acid and methacrylic acid from acetone cyanohydrin
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The present invention relates to a method for producing 2-hydroxyisobutyric acid where acetone cyanohydrin is converted to 2-hydroxyisobutyric acid using an enzyme catalyst having nitrilase activity, or having a combination of nitrile hydratase and amidase activities. The invention also encompasses production of methacrylic acid wherein the 2-hydroxyisobutyric acid produced with the catalyst described is dehydrated to produce methacrylic acid.
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- Anhydrous cosmetic composition with ceramides for firming skin
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A method and cosmetic composition for improving skin firmness are provided through an anhydrous composition including a hydrophobic carrier which may be a silicone or hydrocarbon for delivering an effective amount of a ceramide formed of a sphingoid base linked through an amide to a 2-hydroxycarboxylic C2-C30group.
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- LINK synthesis with 3-hydroxy-1H-pyrazoles: 3-carboxyisoalkyloxy-1H-pyrazoles-bicyclic acylpyrazolium salts and γ-lactams-3-carboxyisoalkyloxy-4,5-dihydro-1H-pyrazol-5-ones
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1-Substituted 3-hydroxy-1H-pyrazoles 1 react with chloroform, NaOH, and aceton resp. butan-2-one O-regiospecifically to yield 2-methyl-2-[(1H-pyrazol-3-yl)oxy]-propanoic resp. -butanoic acids 14 via a dichlorocarbene (12)-dichlorooxirane (9) pathway. Chlorides 17 of 14 easily cyclize to N-acylpyrazolium salts 18/19, which quantitatively afford esters 22-26 and amides 27-29 of 14. Enantiomers of the butanoic acid 14h, obtained via their diastereomeric cholesterol esters, differ in their stimulus to peroxisome proliferation. At 140°C pyrazolium salts 18 undergo thermolysis to bicyclic β-oxa-γ-lactams 30-32. 3-Carboxyisoalkylamino-pyrazoles similarly give 1H-β-aza-γ-lactams 34. Reactions of 14 with surplus SOCl2 result in 6-chloro-37 resp. 7-chloro-β-oxa-γ-lactams 38 via chlorosulfinylation and extrusion of SO, and in 4,4-bispyrazolyl-sulfoxide 39. A mild introduction of additional O-functions into pyrazoles affording 4,5-dihydro-3-hydroxy-5-oxo-1H-pyrazoles 52-57 is presented. Biological effects of the new pyrazoles are protection against shock and ADP-induced thromboembolism, reduction of serum lipids and improvement of blood flow. Johann Ambrosius Barth 1998.
- Dorn, Helmut,Ozegowski, Ruediger
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p. 437 - 449
(2007/10/03)
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- Esters of L-carnitine and acyl L-carnitine with hydoxy acids for producing pharmcaeutical compositions for treating dermatoses
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Dermatosis is treated by a method comprising topically applying an effective amount of an ester of L-carnitine or an acyl L-carnitine with a hydroxy carboxylic acid selected from the group consisting of α-hydroxybutyric acid, α-hydroxyisocaproic acid, α-hydroxyisovaleric acid, malic acid and tartronic acid, to a patient in need thereof.
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- Use of esters of L-carnitine and acyl L-carnitine with hydroxyacids for producing pharmaceutical compositions for treating dermatoses
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The use is disclosed of esters of L-carnitine and acyl L-carnitines with hydroxyacids for producing pharmaceutical compositions suitable to be topically applied for treating dermatoses such as ichthyosis and psoriasis.
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- The Reaction of Dimethyldioxirane with Alkynes
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The reaction of dimethyldioxirane with several alkynes gives products which are conveniently rationalized by postulating the intermediacy of oxirenes and oxocarbenes.The latter serve as precursors to H atom or methyl group migration products, as well as to cyclopropane insertion products in some cases.Alkenes, derived from some of these carbene reactions, are partially converted to epoxides.
- Murray, Robert W.,Singh, Megh
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p. 5076 - 5080
(2007/10/02)
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- Process for producing methacrylic acid
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A process for producing methacrylic acid which comprises: (I) producing acetonecyanohydrin from prussic acid and acetone; (II) hydrating the acetonecyanohydrin obtained in step (I) to form α-hydroxyisobutyric acid amide; (III) reacting the α-hydroxyisobutyric acid amide obtained in step (II) with methyl formate or with methanol and carbon monoxide to form methyl α-hydroxyisobutyrate and formamide; (IV) hydrolyzing the methyl α-hydroxyisobutyrate obtained in step (III) to form α-hydroxyisobutyric acid; (V) dehydrating the α-hydroxyisobutyric acid obtained in step (IV) to form methacrylic acid; and (VI) dehydrating the formamide separated from the products obtained in step (III) to form prussic acid and recycling the prussic acid to step (I) as a starting material. The process is capable of producing methacrylic acid from readily available starting materials with a high yield and selectivity, without forming undesirable by-product or waste materials, such as ammonium sulfate.
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- SYNTHESIS OF HYDROXY CARBOXYLIC ACIDS BY THE OXIDATION OF α-OLEFINS WITH CONCENTRATED NITRIC ACID
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The reaction of propene, 2-methylpropene, 3-chloro-1-propene, and 2-methyl-3-chloro-1-propene with concentrated nitric acid (initial weight fraction 98-91percent) leads to the corresponding α-hydroxy carboxylic acids. The key stage in the oxidation of the α-olefin to the hydroxy acid is its nitrosation, which is promoted by increase in the solvent polarity and in the nucleophilicity of the double bond in the olefin. The introduction of chlorine into the olefin molecule leads to some increase in the probability of nitration.
- Tyurina, R. D.,Gorokhova, T. G.,Rusakova, M. S.,Ustavshchikov, B. F.
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p. 1070 - 1075
(2007/10/02)
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- One-flask preparation of symmetrical ketones and 1,2-diketones from esters
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A convenient one-flask preparation of a series of symmetrical 1,2-diketones from esters is reported using sodium metal induced acyloin condensation followed by reaction with thionyl chloride. Symmetrical monoketones were obtained when after initial acyloin condensation, the reaction mixture is oxidized with aqueous sodium bromate and then reacted with thionyl chloride. Preparative aspects, the scope of the reaction, and the suggested mechanism are discussed.
- Olah,Wu
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p. 1177 - 1179
(2007/10/02)
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- Stereoelectronic Control of the Tertiary Ketol Rearrangement: Implications for the Mechanism of the Reaction Catalysed by the Enzymes of Branched-chain Amino Acid Metabolism, Reductoisomerase and Acetolactate Decarboxylase
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The alkali-catalised rearrangement of (R)--3-hydroxy-3-methylpentan-2-one has been studied.Rearrangement via transition state having an anti arrangement of C-O bonds was preferred over that with a syn arrangement by a factor of 1.8:1.The result is of interest in relation to the mechanism of action of the enzymes reductoisomerase and acetolactate decarboxylase, both of which are involved in the metabolism of the branched-chain amino acids.The structure and relative configuration of the product 23 of bromolactonisation of N-methacryloyl L-proline 22 were determined by X-ray crystallographic analysis.
- Crout, David H. G.,McIntyre, C. Rupert,Alcock, Nathaniel W.
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- ipso Nitration in p-halophenyl ethers
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Addition of nitronium ion ipso to halogen occurs on nitration of the p-haloanisoles in acetic anhydride at -60 deg C.In the cases of p-fluoro- and p-chloro-anisole, addition of the nitronium ion is reversible and only small amounts of ipso products are obtained.With p-bromoanisole nitrodebromination occurs.When p-halophenyl ethers containing a trapping substituent, e.g., 2-(4-chlorophenoxy)-2-methylpropanoic acid, are used as substrates, substantial amounts of the spiro diene with nitro ipso to halogen, e.g., 3,3-dimethyl-8-chloro-8-nitro-1,4-dioxaspirodeca-6,9-dien-2-one, can be isolated.The results demonstrate that extensive ipso attack at the halogen-substituted position is general in the nitration of p-halophenyl ethers.Key words: ipso nitration, ether, diene, p-haloanisole.
- Clewley, Robin G.,Fischer, Alfred,Henderson, George N.
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p. 1472 - 1479
(2007/10/02)
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- A SIMPLE SYNTHESIS AND SOME CHEMICAL PROPERTIES OF BENZO-1,4-DITHIAFULVENES
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The synthesis of benzo-1,4-dithiafulvenes by a simple treatment of 2-substituted 1,3-benzodithiolium tetrafluoroborates - obtained starting from carboxylic acids or acyl chlorides and tetrafluoroboric acid/ ether complex - with acetonitrile water is reported.The reaction is very fast and affords the products in high over-all yields and under mild conditions.The reactions of benzo-1,4-dithiafulvenes with reducing agents (zinc/trifluoroacetic acid and acetonitrile, zinc/deuterated trifluoroacetic acid and acetonitrile, Raney nickel) and with oxidizing agents (hydrogen peroxide/ acetic acid, sodium hypochlorite, chlorine gas/water) are also reported.These reactions show the interesting synthetic potential of benzo-1,4-dithiafulvenes.
- Barbero, Margherita,Cadamuro, Silvano,Ceruti, Maurizio,Degani, Iacapo,Fochi, Rita,Regondi, Valeria
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p. 227 - 236
(2007/10/02)
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- The Reaction of Copper Sulfate with Carboxylic Acids and their Derivatives in Aqueous Solutions under Hydrothermal Conditions
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Under hydrothermal conditions aqueous solutions of copper(II) sulfate (1) are reduced by means of saturated fatty acids with hydrogen at the α-atom to yield crystalline copper.In all cases carbon dioxide is liberated and lower fatty acids and ketones can be identified as reaction products. α-Hydroxy and α-aminocarboxylic acids proved to be very effective reducing agents towards 1.The yield of copper varied from 2 to 2.5 mol Cu per 1 mol of amino acid.The reaction of 1 is suppressed by sulfuric acid.The presence of hydrochloric acid or chlorides leads to the precipitation of copper(I) chloride.The mechanisms of the decomposition of the various types of carboxylic acids is discussed.It was also possible to precipitate metallic copper by means of various proteins. - Key words: Copper, Copper(II) Sulfate, Carboxylic Acids, Hydrothermal Reactions
- Seel, F.,Schuh, J.
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p. 157 - 162
(2007/10/02)
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- Process for the production of methacrylic acid from isobutyraldehyde
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To produce methacrylic acid, firstly, isobutyraldehyde is acetalized. The resultant acetal is cleaved into the isobutenyl ether and alcohol. The isobutenyl ether is oxidized with molecular oxygen or an oxygen-containing gaseous mixture in the presence of an alkaline solution at temperatures of 30°-70° C. to obtain the epoxide. This epoxide is hydrolyzed to the α-hydroxyisobutyraldehyde. The latter is then oxidized with concentrated or fuming nitric acid at temperatures of 20°-110° C. to produce α-hydroxyisobutyric acid, and methacrylic acid is obtained therefrom by splitting off water.
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- HIGH-TEMPERATURE HYDRATION OF ACRYLIC AND METHACRYLIC ACIDS
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In the high-temperature liquid-phase reaction of acrylic and methacrylic acids with water the directions of hydration differ; β-hydroxypropionic and α-hydroxyisobutyric acids respectively are formed, and this agrees with an electrophilic mechanism of hydration.A method is proposed for the production of β-hydroxypropionic acid by hydration of acrylic acid.It was found that competing reactions leading to the formation of oligomers occur during the hydration of methacrylic acid.
- Zil'berman, E. N.,Salov, V. N.,Krasnov, V. L.,Gredniger, M. V.
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- Process for the preparation of antioxidant amides
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An inexpensive and nonhazardous process for the preparation of an amide wherein an organic acid reacting with an aryl amine to form an intermediate hydroxy aryl amide and then dehydrating the hydroxy aryl amide to form a α, β unsaturated amide.
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