METHOD OF PRODUCING METHYLAL (VERSIONS) Russian patent published in 2012 - IPC C07C43/303 C07C41/56 

FIELD: chemistry.

SUBSTANCE: present invention relates to versions of a method of producing methylal, used for cosmetic and industrial purposes, from formaldehyde and methanol using a reaction-rectification technique. One of the versions of the method involves preliminary mixing of aqueous solution of formaldehyde and methanol, feeding the obtained mixture into a pre-reaction zone, subsequently feeding the mixture of unreacted initial reagents, the formed methylal and water into rectification column, having a reaction-rectification zone lying higher than the bottom of the column, condensation of the obtained product which contains over 90 wt % methylal collected from the top of the column. During preliminary mixing, methanol is fed in amount of 95-50% of the amount required to realise the method, and the remaining portion of methanol, in amount of 5-50% of the amount required to realise the method, is fed into the rectification column lower than the reaction-rectification zone. The second version of the method is distinguished by that, during preliminary mixing, aqueous solution of formaldehyde, in amount of 50-95% of the amount required to realise the method, and methanol is fed in amount of 30-80% of the amount required to realise the method, and the remaining aqueous solution of formaldehyde in amount of 5-50% of the amount required to realise the method, and methanol in amount of 0.5-20% of the amount required to realise the method, is fed into the rectification column higher than the reaction-rectification zone, and the remaining portion of methanol, in amount of 5-50% of the amount required to realise the method, is fed into the rectification column lower than the reaction-rectification zone.

EFFECT: disclosed versions of the method increase efficiency of the process owing to higher conversion of reagents and low residual content of methanol and formaldehyde in the waste water.

8 cl, 1 dwg, 9 ex