- Green method for synthesizing high value-added mercaptoacid by catalyzing addition reaction of H2S and olefine acid by using ionic liquid as catalyst
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The invention relates to a green method integrating catalysis, reaction and separation, which is used for producing beta-mercapto carboxylic acid through addition of alpha, beta-unsaturated carboxylic acid and H2S by taking amino-functionalized hydrophobic ionic liquid as a catalyst. H2S is activated through tertiary amine alkaline sites contained in the ionic liquid, so that H2S and double bonds of alpha, beta-unsaturated carboxylic acid are subjected to an addition reaction, and recycling of H2S is realized. The product obtained after the reaction can be subjected to water phase liquid-liquid extraction to realize separation of the catalyst and the product, and the ionic liquid can be recycled. In the system, the ionic liquid is both a catalytic medium and a reaction medium, no other organic solvent participates in the system, H2S is efficiently utilized, meanwhile, high-added-value products such as mercapto acid are obtained, and the method is more economical and environmentally friendly and conforms to the development concept of green chemical industry.
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Paragraph 0041; 0049-0050; 0053-0054; 0057-0059
(2021/05/05)
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- Method for preparing mercaptocarboxylic acid or derivatives thereof by aminolysis of thioureidocarboxylic acid or derivatives thereof
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The invention relates to a method for preparing mercaptocarboxylic acid or derivatives thereof by aminolysis of thioureidocarboxylic acid or derivatives thereof. The method mainly comprises the following steps: 1, dissolving thioureidocarboxylic acid or a derivative thereof in ammonia water or a mixed solution of ammonia water and a cosolvent, heating the system to 40-150 DEG C, and reacting for long time until reaction of the thioureido salt is finished; 2, cooling the reaction system, neutralizing the reaction system by using acid, removing the solvent by using a solvent extraction system, and separating to obtain the mercaptocarboxylic acid or the derivative thereof; and 3, concentrating and filtering the residual water phase or organic phase, recycling the distilled water phase or organic phase, and taking the solid ammonium salt mixture as a nitrogen fertilizer. According to the method, the defects that pollutants are complex and difficult to treat, and the environment is pollutedin the prior art that metal ions such as NaOH are adopted for alkaline hydrolysis of thioureidocarboxylic acid and derivatives thereof to prepare mercaptocarboxylic acid and derivatives thereof are overcome. The method has the advantages of simple process, low cost, no environmental pollution and the like, and can basically realize zero emission of three wastes.
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Paragraph 0012
(2020/06/09)
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- Preparation method of beta-sulfhydryl carboxylic acid compound
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The invention provides a preparation method of a beta-sulfhydryl carboxylic acid compound. A solid base catalyst used in the method has suitable alkali strength, so that not only is hydrogen sulfide enabled to be activated and a reaction promoted to be carried out, but the binding between carboxyl groups and active sites in raw materials or products is also inhibited, and the active sites are prevented from being deactivated slowly. Furthermore, the solid base catalyst selects a polyhydroxy compound as a carrier, and a great deal of hydroxyl groups on the surface of the carrier can promote thehydrogen sulfide to be dissolved in a reaction system and adsorbed on the surface of the catalyst so as to enable the hydrogen sulfide to be migrated to the positions around the active sites for being activated, so that the high conversion rate and high selectivity of the reaction also can be enabled to be reached at the lower pressure, and the catalytic stability is better. In addition, the preparation method is mild in reaction conditions, and the gas-liquid phase reaction is carried out under the conditions of low temperature and low pressure, so that the method is easily applied to industry. Experiments prove that the reaction conversion rate and selectivity of the beta-sulfhydryl carboxylic acid compound prepared by the method are respectively not less than 98% and 88%. After the compound is continuously evaluated for 100h, the catalytic stability of the compound is proved to be better.
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Paragraph 0070; 0075; 0076; 0088
(2018/06/26)
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- METHOD OF PRODUCING β-MERCAPTOCARBOXYLIC ACIDS
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The invention relates to a method for efficiently producing β-mercaptocarboxylic acids using a solid acid catalyst such as zeolite, which product corresponds to respective starting materials selected from α, β-unsaturated carboxylic acids (α, β-unsaturated carboxylic acid, a, β-unsaturated carboxylic acid ester, ex, β-unsaturated amide, a, β-unsaturated aldehide and α, β-unsaturated ketone) and hydrogen sulfides (hydrogen sulfide, sulfide salt and hydrosulfide salt), wherein a solvent compatible with water is used in the reaction. According to the invention, β-mercaptocarboxylic acids which are useful as additives in synthetic materials for pharmaceutical or agricultural agents and in polymer compounds can be industrially produced efficiently by using easily available a, β-unsaturated carboxylic acid (such as crotonic acid) at high yield.
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Page/Page column 31-32
(2009/04/25)
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- Carbodiimides comprising thiocarbamide acid ester groups
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Thiocarbamides comprising at least one carbodiimide group and at least one thiocarbamic ester group of the formula
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- Process for the manufacture of mercaptocarboxylic acids from unsaturated carboxylic acids
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A mercaptocarboxylic acid of formula (I) is prepared by reacting an unsaturated carboxylic acid of formula (II) with a hydrosulphide of formula ASH, A being an alkali metal cation or a cation NR3R4R5R6+, R3to R6each representing H or a hydrocarbon radical, or of formula Q(SH)2, Q being an alkaline-earth metal cation, by acidifying the resulting reaction medium in order to obtain the desired compound (I). According to the present invention, the reaction is carried out with a supply of H2S other than that supplied by the neutralization of the acid (II). In particular, H2S is introduced into the medium by a direct external supply. H2S can also be produced in situ by reacting the hydrosulphide with at least one acid introduced into the medium. The compound (I) is obtained with a very good selectivity.
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Page column 7
(2008/06/13)
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- POLAROGRAPHY OF CARBOXYMETHYLMERCAPTOSUCCINIC ACID (EVAN ACID 3cs) IN AQUEOUS, METHANOL AND ACETONITRILE
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The polarographic behaviour of carboxymethylmercaptosuccinic acid at the D.M.E. in aqueous solutions, methanol and acetonitrile has been investigated in the presence of 0.1 M KNO3 and 0.01 percent thymol with respect to effect of change in pH, concentration, drop time and maximum suppressor on the wave characteristics.Well-defined irreversible cathodic waves were obtained in the aqueous (pH = 5.18), 60 percent V/v methanol (pH = 3.22) and 60 percent V/v acetonitrile (pH = 11.68) media.The defined waves were obtained pH > 3.20 in aqueous solution, pH > 3.22 in aqueous methanol and pH 11.68 in acetonitrile.The mechanism of the electrode process in aqueous, methanol and acetonitrile solutions has also been elucidated.
- Gupta, Keval Chand,Jain, Nita
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p. 407 - 416
(2007/10/02)
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