An Improved Process for the Manufacture of a Product Containing Acetone Cyanhydrin - Patent - Brazilian Privilege No. 7407141 - Continuous Production Process Description

Sep 28, 2026

Uploaded by Ben

An invention describes a continuous process to manufacture a material containing acetone cyanhydrin by reacting hydrogen cyanide with acetone in the presence of an alkaline catalyst selected from sodium hydroxide or sodium carbonate, followed by neutralization with sulfuric acid. Conventional continuous operation suffers from salts re-dissolving after separation and causing obstructions in piping and pumps, reducing equipment efficiency. The improved method uses an excess of sulfuric acid to keep free sulfuric acid in crude acetone cyanhydrin, suppressing salt separation even when heated up to 180°C.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages62

Reading Time2 h 36 min

AccessFree to download

Patent Overview

Continuous Production Objective

Reaction and Catalyst

Neutralization Strategy

Solubility and Temperature Effect

Tanada,Hideo. An improved process for the manufacture of aproduct containing acetone cyanhyarin /by HideoTanaka and otners.13 p. Patent(Brazilian)No.7407141.FILED: TRANSLATION NO.4859.ABSTRACTED oy的at00at的的 mea w人V二ea。女 u2epwelue Nousao tooo2tc 100 Federal Republic of Brazil Publication of Request for Privilege No.7407141 Date of Deposition 8/28/74 Title: An Improved Process for the Manufacture of a ProductContaining Acetone Cyanhydrin Deposer: Nitto Chemica1 Industry Co.,Ltd. Inventor: Hideo Tanaka et al. "An Improved Process for the Manufacture of Product Containina Acetone Cyanhydrin" This invention is related to a continuous process for the pro-duction of a material which contains acetone cyanhydrin,by meansof the reaction of hydrogen cyanide with acetone,in the presenceof an a1kaline catalyst selected from the group that consists ofsodium hydroxide and sodium carbonate,and neutralization of theresultant alkaline acetone cyanhydrin with sulfuric acid. In a genera1 way,the acetone cyanhydrin is synthesized bymeans of the reaction of hydrogen cyanide with acetone in thepresence of a sma11 quantity of an alkaline catalyst in accordancewith the following equation: The reaction is in a state of equilibrium in the presence ofthe alkaline cata1yst,and the equilibrium is dependent signifi-cant1y on the temperature. The equilibrium is shifted in the dir-ection to the side of the acetone cyanhydrin at the very low(=1ow-er)temperatures. In order to obtain an acetone cyanhydrin in a good yield,itbecomes necessary to carry out the reaction at a low temperature,and to remove the alkaline catalyst upon the completion of the re-action,in order to impede the reversal of the reaction. In accordance with the conventional industrial processes forthe production of the acetone cyanhydrin,the hydrogen cyanide and Digitized by the Internet Archivein 2019 https://archive.org/details/improvedprocessf0Otana —2— the acetone are safely subjected to the reaction in the presenceof an a1kaline catalyst,such as sodium hydroxide,sodium carbonateand the like,usually at a temperature not more than 50°c,andpreferrential1y at -20c to +20c,and upon the completion of thereaction,the solution of the resultant reaction materials,main-tained at a low temperature,is given an addition of sulfuric acid,in order to neutralize the alkaline catalyst and to impede the re-versa1 of the reaction. Then,there is a separation for the care-fu1 remova1 of the neutralization materials,and the crude acetonecyanhydrin that results is purified in the usual manner by meansof a distillation under a vacuum,and by means of its being heated. However,whenever the conventional process is operated in acontinuous manner,there are neutralization materials stil1 dis-solved in the aforementioned acetone cyanhydrin crude materialwhich separates again upon its being heated,and in order to purifythe aforementioned crude acetone cyanhydrin,frequent1y,an acci-denta1 obstruction of the piping and the pumps takes place,and inthe lines from the neutralization stage into the lines of the puri-fication staqes,owing to the aforementioned separation of thesesalts(=materials)。 For that very reason,the efficiency of theactua1 operation within the continuous processing equipment becomesreduced considerably. Therefore,there is an advantage for theconventional process,when operating continuously. The objective of the present incention is to provide an improvedrocess for the production of acetone cyanhydrin in a continuous —3— manner,which is capable of overcoming the aforementioned dis-advantages which arise from the separation of the salts from theneutralization. That is to say,the objective of the present in-vention is to provide a means for the insurance of a process forthe continuous production of acetone cyanhydrin,by means of theelimination of the accidental obstruction of the piping and thepumps,occurring in the separatio

FAQs

What raw materials and catalysts are used to produce acetone cyanhydrin in this process?

Hydrogen cyanide reacts with acetone in the presence of an alkaline catalyst selected from sodium hydroxide or sodium carbonate.

How does the invention address problems seen in conventional continuous processing?

It prevents salt separation issues that can re-dissolve in crude acetone cyanhydrin and cause accidental obstruction of piping and pumps, improving operational efficiency.

Why is sulfuric acid used in an excess quantity during neutralization?

The process adds sulfuric acid above the theoretical neutralization amount to maintain free sulfuric acid in the crude product, suppressing separation of salts from neutralization.

Sep 28, 2026

Uploaded by Ben