Abstract: A process for manufacturing esters from acid and alcohol and a system thereof are provided, wherein the system includes a reactive distillation column, a sidestream reactor packed with catalyst, and a decanter for conducting the method. The method is carried out by (a) extracting a first mixture of acid and alcohol from the reactive distillation column, for then feeding the first mixture to at least one sidestream reactor packed with catalyst to obtain a reaction product; (b) feeding the reaction product from the sidestream reactor to the reactive distillation column, allowing a second mixture of alcohol, ester and water to be separated from a top end of the reactive distillation column; (c) feeding the second mixture into the decanter to separate an organic phase from an aqueous phase; and (d) separating esters from the organic phase.

Abstract: The present invention relates to a process for producing carboxylic acid anhydrides, in which a carboxylic acid ester, derived from an alcohol and a carboxylic acid, and carbon monoxide containing a small amount of hydrogen are used as raw materials and subjected to a carbonylation reaction in a liquid reaction medium in the presence of a Group VIII B catalyst to produce a carboxylic acid anhydride. The reaction medium comprises the Group VIII B catalyst, an organic halide, the carboxylic acid ester, an alkali metal salt, at least one organic promoter, the carboxylic acid anhydride and the carboxylic acid, wherein the organic promoter is selected from at least one of the following structural forms (I), (II) and (III). According to the process of the present invention, the reaction rate of the carbonylation reaction is increased by the use of the specified organic promoters.

Abstract: A method for preparing organic carbonates comprising subjecting an alcohol compound to oxidative carbonylation in the presence of carbon monoxide, oxygen and a liquid-phase catalytic system, to form a organic carbonates, wherein the liquid-phase catalytic system includes at least one catalyst, at least one additive and at least one ionic liquid composed of a cation, which has a nitrogen-containing heterocyclic structure, and an anion. Through using the additive and the ionic liquid, the activity and the performance of the catalyst are enhanced, and increased reaction rate and yield can be obtained.

Abstract: Provided is a process for preparation of dialkyl carbonates, comprising the step of performing oxidative carbonylation of an alcohol in liquid phase in the presence of CO and O2, to form dialkyl carbonate in a catalyst system comprising a metal halide as catalyst and at least one nitrogen-containing compound selected from the group consisting of imidazole derivatives (excluding unsubstituted imidazole), benzoimidazole derivatives, pyridazine derivatives, carbazole, acridine and non-cyclic amines as auxiliary catalyst. The process of the invention, by using above catalyst system, can increase the conversion ratio of alcohol and the selectivity of the oxidative carbonylation reaction, thus increasing the total yield of dialkyl carbonate. In addition, the process of the invention has the advantages of reducing the required amount of the catalyst and causing less corrosion to the reactor.

Abstract: A method for preparing hydroxylamine is provided that includes the steps of (i) pretreating an acidic buffer solution; and (ii) reducing nitrate ions in the acidic buffer solution with hydrogen to give hydroxylamine in the presence of catalysts, wherein the pretreatment is performed by adding a precipitant represented by formula (I) to the acidic buffer solution, [(A)aM(CN)6.xH2O]??(I) allowing the metal impurities in the acidic buffer solution to react with the precipitant to form metal complex, and then to remove the metal complex. The metal complex is formed and separated by pretreating the acidic buffer solution with a specific precipitant without adjusting pH and changing the composition of the acidic buffer solution prior to hydroxylamine synthesis, thus enhancing the selectivity of the hydroxylamine production.

Abstract: A method for preparing hydroxylamine, comprising the steps of: (i) pretreating the acidic buffer solution with the compounds having a functional group represented by formula (I), thereby removing metal impurities from the acidic buffer solution; and (ii) reducing nitrate ions in the acidic buffer solution with hydrogen to give hydroxylamine in the presence of catalysts, According to the present invention the selectivity for reducing nitrate ions to give hydroxylamine can be significantly enhanced.

Abstract: Provided is a process of producing cyclohexanone oxime comprising the steps of: pre-mixing an inorganic process solution containing a high concentration of hydroxylamine phosphate with a first stream of cyclohexanone such that the concentration of hydroxylamine phosphate is reduced to 80% or less of its initial concentration; and subjecting hydroxylamine phosphate in the premixed inorganic process solution to an oximation reaction with a second stream of cyclohexanone. According to the process, oximation is performed after the inorganic process solution containing a high concentration of hydroxylamine phosphate has been pre-mixed with the first stream of cyclohexanone to reduce the concentration of hydroxylamine phosphate. As a result, not only that the efficiency of oximation and the yield of cyclohexanone oxime are increased, but also the organic content of the inorganic process solution discharged from the oximation tower is reduced.

Abstract: A recycling system for hydroxylamine formation and oximation is proposed. The recycling system includes a hydroxylamine formation zone, an oximation zone, a purification zone, and an adjusting zone having a nitrate absorption tower. An inorganic process solution, used by the recycling system, partially enters the nitrate absorption tower supplementing nitrate, followed by mixing with the residual inorganic process solution, thereby reducing the loss rate of hydroxylamine in the inorganic process solution due to degradation. In addition, the organic impurities with high boiling point in the inorganic process solution can be effectively removed in the purification zone. As a result, the reduced activity or selectivity of the catalyst for hydroxylamine formation, caused by the toxic effects of these organic impurities on the catalyst, can be avoided, and hence, a high concentration of hydroxylamine can be obtained.

Abstract: A method for preparing hydroxylamine by reducing nitric acid or its salt with hydrogen gas in an aqueous medium in the presence of a catalyst, wherein reduction of nitric acid or its salt is performed in a reactor comprising a reaction section, a cooler disposed at the lower portion of the reactor, and a middle gas distributor and a lower gas distributor respectively disposed above and below the cooler for introducing hydrogen gas into the reaction section. According to the present invention, gas distribution become more uniform by disposing the gas distributors at different positions of the reactor, which results in higher yield of hydroxylamine.

Abstract: A method for preparing hydroxylamine by reducing nitric acid or its salt with hydrogen gas in an aqueous medium in the presence of a catalyst, wherein reduction of nitric acid or its salt is performed in a reactor comprising a reaction section, a cooler disposed at the lower portion of the reactor, and a middle gas distributor and a lower gas distributor respectively disposed above and below the cooler for introducing hydrogen gas into the reaction section. According to the present invention, gas distribution become more uniform by disposing the gas distributors at different positions of the reactor, which results in higher yield of hydroxylamine.

Abstract: A process for preparing a carboxylic acid by the carbonylation of an alcohol in a reaction medium is provided. The reaction medium includes a catalyst promoter having a metal species selected form the group consisting of group IIIA-IVA metals, group IB-VIIIB metals and lanthanides, together with a hydrohalic acid to prevent catalyst precipitation and to maintain high reaction rates in case of low water content.

Abstract: A system for purifying an aqueous solution of crude caprolactam is provided, which includes a filtration zone (A), an inspection unit (B), a purification zone (C), and a first temporary storage tank (D). The filtration zone (A) contains a filtration apparatus though which an aqueous solution of crude caprolactam is filtered to remove ionic impurities therein, so as to obtain caprolactam-containing filtrate; the inspection unit (B) is used for judging the filtrate from the filtration zone (A) meets the preset inspection standards; the purification zone(C) is used for concentrating and further purifying filtrate meeting the preset inspection standards, thereby forming a final caprolactam product; and the first temporary storage tank (D) is used for receiving the filtrate not meeting the preset inspection standards, which is then mixed with the aqueous solution of crude caprolactam and delivered back to the filtration zone (A).

Abstract: A method for preparing hydroxylamine, comprising the steps of: (i) pretreating the acidic buffer solution with the compounds having a functional group represented by formula (I), thereby removing metal impurities from the acidic buffer solution; and (ii) reducing nitrate ions in the acidic buffer solution with hydrogen to give hydroxylamine in the presence of catalysts, According to the present invention the selectivity for reducing nitrate ions to give hydroxylamine can be significantly enhanced.

Abstract: A steam stripping device for an inorganic processing solution is provided, which includes a steam stripping unit for heat stripping the inorganic processing solution; a heat exchanging unit coupled to the steam unit for heating the inorganic processing solution; and a desuperheating unit for decreasing the temperature of a steam when overheated before the steam is fed into the heat exchanging unit by cooling liquid. The device can be applied to the inorganic processing solution for removing organic contaminants contained therein. By the provision of the desuperheating unit, the adverse influence on the inorganic processing solution caused by partially superheating can be prevented.

Abstract: Provided is a method for manufacturing hydroxylamine. In this method, an aqueous reaction medium containing acidic buffer agent and nitrate ions in the presence of a limited amount of metal impurities such as Fe or Cu is introduced into a hydroxylamine synthesis reactor in the presence of catalyst to proceed hydroxylamine synthesis by reduction of nitrate ions with hydrogen gas as reducing agent in the aqueous reaction medium to produce hydroxylamine. The reaction is processed in the aqueous reaction medium with a limited amount of metal impurities or even without metal impurities, such that the selection rate of the hydroxylamine product is increased.

Abstract: A process for producing a carboxylic acid having (n+1) carbon atoms, which includes carbonylating an alcohol having n carbon atoms, and/or an ester of the alcohol and the carboxylic acid in each alkyl group with carbon monoxide in the presence of a catalytic system containing a rhodium catalyst. The process uses a reaction medium for the carbonylation that includes: (1) a rhodium catalyst, (2) an organic halide corresponding to said alcohol, (3) an ester of the alcohol and the carboxylic acid, (4) the carboxylic acid, optionally (5) water, a haloid acid, an inorganic halogen salt or an acetate, and (6) a cocatalyst selected from arginine, N-acetyl alanine, or nitrogen- and oxygen-containing organic compounds.

Abstract: The invention relates to a polymer-supported carbonylation catalyst and its use in a process for preparing organic carboxylic acid or anhydride having n+1 carbon atoms. The invention relates also to a process for preparing organic carboxylic acid or anhydride having n+1 carbon atoms by carbonylating with monoxide, in the presence of the above-mentioned carbonylation catalyst, on alcohols having n carbon atoms, ethers having 2n carbon atoms or esters formed from said alcohols and acids. In particular, the invention relates to a process for preparing acetic acid by carbonylating methanol with carbon monooxide in the presence of said carbonylation catalyst. By using said carbonylation catalyst, the temperature for carbonylation can be lowered to about 160° C. with a reaction rate better than that of a traditional process, while the tendency of catalyst precipitation in the course of carbonylation can be improved also.

Abstract: The present invention relates to an improved process for producing an organic carboxylic acid having (n+1) carbon atoms by reacting an alcohol having n carbon atoms with carbon monoxide in the presence of a rhodium catalyst system. More particularly, the present invention relates to carbonylation of alcohol such as methanol catalyzed by a rhodium system to produce acetic acid. The characteristic of the present invention is the addition of a catalyst stabilizer in the reaction medium to avoid or to alleviate the precipitation of the catalyst in the liquid phase. The catalyst as used herein is a an inorganic salt of alkaline metal having the following formula (A): XnMm  (A) X=Li+, Na+, K+; M=CO3−2, HCO3−, PO4−3, HPO4−2, H2PO4−, SO4−2, HSO4−, C2O4−2, HC2O4−, B(C6Y5)4−1; Y=H, F or CF3.

Abstract: A method of recovering adipic acid and 6-hydroxycaproic acid from the waste solution of alkali metal salts of organic acids coming from the process of cyclohexane oxidation, which comprises:(i) basifying the reaction mixture coming from cyclohexane oxidation with an aqueous solution of an alkali-metal base so that the organic acids essentially comprising adipic acid and 6-hydroxycaproic acid therein, are saponified, extracting the formed alkali metal salts of organic acids from the mixture with water, then acidifying the aqueous extract comprising the alkali metal salts of organic acids to a pH value of 3 or lower with an aqueous solution of a protic inorganic acid, as a result, said aqueous extract is separated into an oily layer and an aqueous layer;(ii) extracting the organic acid from said oily layer obtained from the step (i) with an aqueous solution of a protic inorganic acid, to obtain an aqueous extract;(iii) extracting the organic acid from the aqueous layer obtained from the step (i) with an organic

Abstract: The present invention provides a polishing composition which comprises 100 weight part of water; 0.5 to 20 weight part of boehmite, a hydroxide of aluminum, pseudoboehmite or mixtures thereof; 1 to 50 weight part of aluminum oxide (Al.sub.2 O.sub.3); and 1 to 20 weight part of an acidic solution. The polishing composition of the present invention is a thixotropic fluid and displays satisfactory suspension properties. Therefore, it is very suitable for use as a polishing slurry.