Patent GB-615634-A (GB)
Title: Improvements in and relating to the production of chlorine-containing formals
IPC: C07D319/06
Filed: 1945-11-19
Abstract: Chlorine-containing formals are produced by interacting in a liquid reaction medium and in the presence of an acidic catalyst, acetylene, hydrogen chloride and formaldehyde or a polymer of formaldehyde, e.g. paraformaldehyde, alpha-polyoxymethylene or trioxane which under acidic conditions will react as formaldehyde. The formaldehyde may be added to a solution of an acidic catalyst in aqueous hydrochloric acid and acetylene passed into the mixture or acetylene and hydrogen chloride may be passed into a solution of an acidic catalyst in an aqueous solution containing formaldehyde.  The reaction is preferably effected in aqueous medium.  Specified acidic catalysts are zinc chloride, ferric chloride, cadmium chloride, aluminium chloride, stannic chloride and sulphuric acid.  In an example, zinc chloride is dissolved in hydrochloric acid, paraformaldehyde added to the solution and acetylene passed through the mixture at 60 DEG  C.  The supernatant layer which separates from the reaction mixture is removed and the remainder of the reaction product extracted with methylene chloride.  The product fractions are purified by treatment with a solution of sodium carbonate until neutral and then with sodium acid sulphite to remove formaldehyde.  Fractional distillation of the combined products under reduced pressure yields a low-boiling and a high-boiling fraction.  Hydrolysis of each fraction with dilute hydrochloric acid in the presence of phloroglucinol gives phloroglucinol formaldehyde resin, about one mol. of formaldehyde being removed per mol. of each product fraction, indicating the presence of one formal grouping.  Further tests show that the low-boiling fraction is substantially pure 5-di-chlormethyl-1,3-dioxane, while the higher boiling fraction appears to be a mixture of isomeric formals having the empirical formula C10H17O3Cl5.  The residue after re moving the high boiling fraction is a resinous material probably containing polymeric formals produced by reactions involving formaldehyde and several molecules of the chlorinated glycols CH2OH.CHCl.CHCl.CH2OH and CH.Cl2.CH (CH2OH)2 which are probably intermediates in the process.  When the reaction is carried out in acetic acid as reaction medium and with zinc chloride as catalyst the product is mainly 5-dichlormethyl-1,3-dioxane but an acetic ester CHCl2.CH(CH2OOCCH3)2 or the isomeric ester CH3COOCH2.CHCl.CHCl.CH2OOCCH3 is also obtained. Other aliphatic acids containing from 1 to 4 carbon atoms may also be used as reaction media.  The products may be used as insecticides and the linear formal C10H17O3Cl5 may also be used as a plasticiser for chemical compounds and compositions.ALSO:Chlorine-containing formals are produced by interacting in a liquid reaction medium and in the presence of an acidic catalyst, acetylene, hydrogen chloride and formaldehyde or a polymer of formaldehyde, e.g. paraformaldehyde, alpha-polyoxymethylene or trioxane, which under acidic conditions will react as formaldehyde.  The formaldehyde may be added to a solution of an acidic catalyst in aqueous hydrochloric acid and acetylene passed into the mixture or acetylene and hydrogen chloride may be passed into a solution of an acidic catalyst in an aqueous solution containing formaldehyde.  The reaction is preferably effected in aqueous medium.  Specified acidic catalysts are zinc chloride, ferric chloride, cadmium chloride, aluminium chloride, stannic chloride and sulphuric acid.  In an example, zinc chloride is dissolved in hydrochloric acid, paraformaldehyde added to the solution and acetylene passed through the mixture at 60 DEG  C.  The supernatant layer which separates from the reaction mixture is removed and the remainder of the reaction product extracted with methylene chloride.  The product fractions are purified by treatment with a solution of sodium carbonate until neutral and then with sodium acid sulphite to remove formaldehyde. Fractional distillation of the combined products under reduced pressure yields a low boiling and a high boiling fraction. Hydrolysis of each fraction with dilute hydrochloric acid in the presence of phloroglucinol gives phloroglucinol formaldehyde resin, about one mol. of formaldehyde being removed per mol. of each product fraction, indicating the presence of one formal grouping.  Further tests show that the low boiling fraction is substantially pure 5-di-chlormethyl-1,3-dioxane while the higher boiling fraction appears to be a mixture of isomeric formals having the empirical formula C10H17O3Cl5. The residu after removing the high boiling fraction is a resinous material probably containing polymeric formals produced by reactions involving formaldehyde and several molecules of the chlorinated glycols CH2OH.CHCl.CHCl.CH2OH and CH.Cl2.CH(CH2OH)2 which are probably intermediates in the process.  When the reaction is carried out in acetic acid as reaction medium and with zinc chloride as catalyst the product is mainly 5-dichlormethyl-1,3-dioxane, but an acetic ester CHCl2.CH(CH2 OOCCH3)2 or the isomeric ester CH3COOCH2. CHCl.CHCl.CH2OOCCH3 is also obtained.  Other aliphatic acids containing from 1 to 4 carbon atoms may also be used as reaction media.  The products may be used as insecticides and the linear formal C10H17O3Cl5 may also be used as a plasticiciser for chemical compounds and compositions.