Patent GB-577749-A (GB)
Title: Improvements in and relating to the polymerisation of linear formals and esters thereof
IPC: D06P1/651
Filed: 1943-02-19
Abstract: Polymers are produced by polymerizing in the presence of an inorganic acidic polymerization catalyst, one or more linear formals or one or more linear formal esters of polybasic aliphatic acids or of alkoxymethoxy monocarboxylic acids, the said linear formals or esters containing at least two formal groups (-OCH2O-) or at least one formal and a hydroxyl group. Suitable monomers which may be polymerized are methyl, ethyl, propyl or butyl-b -hydroxyethyl formal, methoxyethyl-b -hydroxyethyl formal, methyl, ethyl, propyl, butyl or methoxyethyl-b -hydroxypropyl formal, di - (b  - hydroxyethyl) formal, di - [b  - (hydroxy - ethoxy) methoxy] ethane, di - [b  - (hydroxy - ethoxy) methoxyethyl] formal, compounds of the formula HOCH2CH2(OCH2OCH2CH2)xOH where x is 3 or more, compounds of the formula ROCH2OCH2CH2OCH2OR, where R is a lower alkyl group, e.g. butyl, the (methoxy methoxy) ethanol esters of oxalic, malonic, succinic, glutaric, adipic or higher aliphatic dibasic acids, the b -(alkoxymethoxy) ethyl esters of alkoxymethoxy carboxylic acids or of 1,1-di-(carboxymethoxy) methane these latter esters being obtained by ester interchange in the presence of an alkaline catalyst, e.g. sodium methoxide of 1,1-di-(carbomethoxymethoxy) methane and the alkoxymethoxyethanol. Low molecular weight polymers of these compounds may be converted to polymers of higher molecular weight by the process of the invention.  The reaction may be effected at temperatures between -80 DEG  C. and 300 DEG  C. and at pressures from sub-atmospheric up to 1000 atmospheres.  Suitable catalysts are sulphuric acid, phosphoric acid, hydrochloric acid, hydrofluoric acid alone or with boron trifluoride, boron trifluoride (including its complexes with water, acids, esters, alcohols) aluminium chloride, aluminium bromide, ferric chloride, sodium acid sulphate, sodium acid phosphate, or silica gel.  The catalysts may be supported on carriers such as charcoal, silica gel (this may also be used as a catalyst on its own), or kieselguhr.  Reaction products may be removed from the reaction zone to force the reaction in one direction until the desired molecular weight distribution in the final product is obtained.  If desired, the removed reaction products may be separated, undesired products being returned to the reaction mixture. Typical reaction times are 0.5-10 hours at 25-150 DEG  C. or 1-10 days at temperatures below 0 DEG  C.  The reaction is stopped by removal or neutralization of the catalyst. A solvent for the monomer and polymer, e.g. 1.4-dioxane, benzene or toluene, may be present. If desired, polymerizable alkylene oxides may also be present, e.g. ethylene oxides, 1.2- or 1.3-propylene oxide, tetramethylene oxide or isobutylene oxide.  A very large number of uses for the products of the invention, either alone or in solution in water or other solvent, are listed in the Specification.  They include uses in the textile, leather, rubber, paint, dyeing, paper and lubricating fields, in insecticides, fungicides, protective coatings, as plasticisers, emulsifying or binding agents, in inks, as sizes, in oil or gas well-drilling, or flotation treatments, in plating baths and many others.  Examples describe: (1) and (2) the polymerization of (methoxymethoxy) ethanol in presence of sulphuric acid at 40-50 DEG C. and 28 mm. pressure.  Low-boiling materials were collected in a trap cooled with solid carbon dioxide between the pump and the reaction vessel.  The catalyst was neutralized with sodium methoxide and the product fractionally distilled under reduced pressure; (3) the polymerization of b -(methoxymethoxy) ethyl (methoxymethoxy) acetate in presence of sulphuric acid subsequently neutralized with ammonia; (4) the polymerization of di-(methoxymethoxy) ethane in presence of boron fluoride, which was destroyed at the end of the reaction with anhydrous ammonia, the product being dissolved in benzene, filtered and freed from benzene by distillation at reduced pressure; and (5) the polymerization of di-(methoxymethoxy) ethyl adipate in presence of sulphuric acid.  The products of all the examples are liquids.