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Patent
Wanhua Chemical Group Co. | Date: 2017-04-19

A heater for heating and vaporizing droplets in gas stream, comprising a heater housing and a heater body located inside the heater housing, wherein the heater housing is provided with an airflow inlet and an airflow outlet, the airflow enters into the heater housing via the airflow inlet, flows through the heater body, and then is discharged via the airflow outlet; the heater body comprises a stereoscopic network structure formed by interweaving one or more electrical heating wires. The use of the heater and a method for preparing isocyanate using the heater. The heater has a simple structure, a low pressure loss, uniform heating and a high heat utilization ratio during preparing isocyanate.


Patent
Wanhua Chemical Group Co. | Date: 2017-05-24

Provided is a method for preparing hydroxyethyl (methyl)acrylate by a process of a combination of a three-stage tubular reactor and a tower reactor, wherein, firstly, a catalyst, a polymerization inhibitor and (methyl) acrylic acid are mixed until the solids are dissolved, then mixed with a part of ethylene oxide and thereafter enter into a first tubular reactor for a reaction, a reaction liquid flowing out from the first tubular reactor is mixed with a certain amount of ethylene oxide and enters into a second tubular reactor for a reaction, a reaction liquid flowing out from the second tubular reactor is then mixed with a certain amount of ethylene oxide and thereafter enters into a third tubular reactor, and a reaction liquid flowing out from the third tubular reactor is then passed through a stage of an adiabatic tower reactor and aged such that a product liquid is obtained from extraction. The process has an obviously improved reaction efficiency, can further improve the production yield and reduce the production of impurities such as diesters, monoesters, etc., in the reactions, achieves a continuous production, and reduces the operational risk of the devices.


Patent
Wanhua Chemical Group Co., Wanhua Chemical Guangdong Co. and Wanhua Chemical Ningbo Co. | Date: 2016-07-20

A polyisocyanate modified with sulphamic acid and a mixture thereof, the preparation method thereof, and the use thereof in the production of polyurethane, especially as a cross-linking ingredient in the field of aqueous coatings and adhesives containing groups that are capable of reacting with isocyanate groups.


Patent
Wanhua Chemical Group Co. and Wanhua Chemical Ningbo Co. | Date: 2016-07-06

The present invention relates to a method for preparing branched polycarbonate with a continuous two-phase interface phosgene method. Firstly, an aqueous solution of alkali metal hydroxide with triphenol and polyphenol dissolved therein reacts with a certain amount of phosgene in the present of inert organic solvent to prepare a prepolymer, and then a coupling reaction is performed among the prepolymer, an aqueous solution of alkali metal hydroxide with bisphenol and phosgene dissolved therein to finally obtain a polycarbonate resin. The method can avoid a cross-linking reaction, reduce the cost and improve the quality of the product, while improving the conversion ratio of the branching agent and the branching degree of the product.


Patent
Wanhua Chemical Group Co. | Date: 2016-10-26

A method for continuously preparing biuret polyisocyanate, comprising: a mixed solution of a diisocyanate and a catalyst with water vapour, in an aerosol form, are continuously reacted in a first reactor; the product obtained therefrom is brought into a second reactor for a further reaction; a tail gas from the second reactor is condensed and refluxed, and the non-condensable gas is brought into a tail gas treatment system; a reaction liquid obtained in the second reactor is further reacted in a third reactor; and then separation is performed for removing monomers, so as to obtain biuret polyisocyanate.


Patent
Wanhua Chemical Group Co. and Wanhua Chemical Ningbo Co. | Date: 2016-03-30

Disclosed is a method for preparing diamino-dicyclohexyl methane (H_(12)MDA) by hydrogenation of diamino-diphenyl methane (MDA). In the process, 4,4-MDA used as the starting material is firstly hydrogenated to prepare 4,4-H_(12)MDA. When the activity of the catalyst is reduced, the feed is switched from 4,4-MDA to the mixture of 2,4-MDA and 4,4-MDA, and then when the conversion is stabilized, the feed is switched to 4,4-MDA again. The deactivated catalyst is activated on line by switching the feed to the mixture of 2,4-MDA and 4,4-MDA. 4,4-H_(12)MDA having the trans-trans isomer content of 16~24wt% is produced, and the mixture of 2,4-H_(12)MDA and 4,4-H_(12)MDA is also produced, wherein the content of 2,4-H_(12)MDA in the mixture is 4~15 wt%.


Patent
Wanhua Chemical Group Co. and Wanhua Chemical Ningbo Co. | Date: 2014-01-27

The present invention relates to a method for preparing catalyst used for preparing chlorine by oxidizing hydrogen chloride. The method is mixing a slurry mainly containing boron and chromium with a slurry mainly containing copper, boron, alkali-metal elements, rare-earth elements, aluminum sol, silica sol, carrier and optionally other metal elements, the mixing temperature being not more than 100 C., and the residence time being not more than 120 minutes, the mixed slurry is successively treated with spray drying, high temperature calcination, so that the catalyst is obtained. The present invention also relates to the catalyst prepared through the method, use of the catalyst used in the process of preparing chlorine by oxidizing hydrogen chloride and a method for preparing chlorine by using the catalyst. The catalyst is used for preparing chlorine by oxidizing hydrogen chloride with oxygen or air in fluidized bed reactor.


A solvent refining method for isocyanate prepared by the phosgene method and multistage absorbing towers used in same. Solvent to be refined which contains water, iron, and/or phosgene, hydrogen chloride and other materials with color is dealt by the present method and multistage absorbing towers, which can effectively prevent a drying agent from absorbing water and hardening, partial overheating in the tower and generating channeling. Meanwhile, the pressure drop is effectively lowered. In addition, the content of water is 50 ppm, the content of iron is 5 ppm, the content of phosgene and hydrogen chloride is 20 ppm, PtCo chroma is 20 in the refined solvent. Therefore, the refined solvent can be used as the solvent for preparing isocyanate in the phosgene method and remarkably improve an L color of isocyanate.


Patent
Wanhua Chemical Group Co. and Wanhua Chemical Ningbo Co. | Date: 2016-11-30

The present invention relates to a method for preparing catalyst used for preparing chlorine by oxidizing hydrogen chloride. The method is mixing a slurry mainly containing boron and chromium with a slurry mainly containing copper, boron, alkali-metal elements, rare-earth elements, aluminum sol, silica sol, carrier and optionally other metal elements, the mixing temperature being not more than 100C, and the residence time being not more than 120 minutes, the mixed slurry is successively treated with spray drying, high temperature calcination, so that the catalyst is obtained. The present invention also relates to the catalyst prepared through the method, use of the catalyst used in the process of preparing chlorine by oxidizing hydrogen chloride and a method for preparing chlorine by using the catalyst. The catalyst is used for preparing chlorine by oxidizing hydrogen chloride with oxygen or air in fluidized bed reactor, and has an excellent activity and anti-caking property, a relatively good mechanical strength and a relatively long service life.


Patent
Wanhua Chemical Group Co. and Ningbo Wanhua Polyurethanes Co. | Date: 2015-10-14

The present invention provides a method for preparing 3-aminomethyl-3,5,5-trimethyl cyclohexylamine. The method comprises: a) reacting 3-cyano-3,5,5-trimethyl cyclohexanone with excess primary amine as well as removing the water generated from the reaction, so that IPN is substantially converted into imine compounds; b) in the presence of an ammonolysis catalyst, mixing the product of step a) with liquid ammonia, making the imine compound perform ammonolysis reaction to generate 3-cyano-3,5,5-trimethyl cyclohexylimine and the primary amine; and c) in the presence of hydrogen and a hydrogenation catalyst, hydrogenating 3-cyano-3,5,5-trimethyl cyclohexylimine obtained in step b) to obtain 3-aminomethyl-3,5,5-trimethyl cyclohexylamine. The method of the present invention avoids the generation of 3,5,5-trimethyl cyclohexanol and 3-aminomethyl-3,5,5-trimethyl cyclohexanol as the major by-products in the prior art, thereby improving the yield of 3-aminomethyl-3,5,5-trimethyl cyclohexylamine.

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