Patent GB-379674-A (GB)
Title: Improvements in the manufacture and production of polymerisation products of vinyl ethers
IPC: C09J123/00
Filed: 1931-05-30
Abstract: Vinyl ethers are polymerized by employing as polymerizing agents absorptive materials, such as absorptive hydrosilicates, e.g. Florida earth and the absorptive hydrosilicates obtainable in commerce as bleaching earths under the trade names Tonsil, Granosil, Terrana or Isarit, or under the Registered Trade Mark "Frankonit," also active carbon, kieselguhr, precipitated silica (silicon substratum) metals finely divided on carriers, e.g. the non-alkaline metals of groups 1 and 8 of the periodic system suitable for hydrogenations and dehydrogenations, such as copper, silver, gold, iron, cobalt, nickel and the metals of the platinum group, precipitated on carriers of large superficial area such as Fuller's earth, silica gel, asbestos, active charcoal or pumice.  Bleaching earths having an acid reaction, e.g. Tonsil HC or AC or Granosil, are especially suitable, but bleaching earths having a neutral reaction, e.g. Terrana neutral, or those having an alkaline reaction, e.g. those sold under the Registered Trade Marks "Floridin S, S.G., or B.B." also have a satisfactory effect, especially when neutralized or preferably acidified with small amounts of acid substances such as halogen hydracids, alum, aluminium sulphate, potassium bisulphate, zinc chloride or acidrreacting inorganic salts.  The polymerization may be carried out in the liquid or gaseous phase, in the latter case with the employment, if desired, of inert diluents such as carbon dioxide, nitrogen, methane or carbon monoxide.  The liquid phase reaction may be performed in the presence of inert liquid diluents, e.g. saturated ethers such as diethyl, ethyl n-butyl, di-n-butyl or ethyl propyl ethers, or hydrocarbons such as benzene, toluene, xylene, decahydronaphthalene or benzene, but preferably without diluents. Preferably the vinyl ether is introduced in the liquid or gaseous state at the top of a vertical vessel, capable of being heated and cooled, charged with the absorptive substance, preferably in small quantities mixed with inert filler bodies such as balls or rings of glass or clay, the polymerization product being withdrawn from the lower end of the vessel.  In order to obtain a better withdrawal of the reaction heat it is advantageous to work so that a portion of the vinyl ether leaves the reaction space unaltered and is returned to the reaction vessel.  When employing less active, e.g. alkaline or neutral, polymerizing agents, a slight warming, e.g. to 40 DEG  C., is desirable.  When working in the liquid phase in the presence of a liquid diluent, the reaction temperature may be raised to the boiling point of the diluent, the vinyl ether being advantageously gradually added to the diluent which is kept boiling and contains the polymerizing agent suspended therein.  In the vapour phase reaction, temperatures up to 250 DEG  C., but preferably between 60 DEG  and 100 DEG  C., may be employed.  Vinyl ethers of the general formula <FORM:0379674/IV/1> , where R is an aliphatic, aromatic or hydroaromatic radicle and R1, R2 and R3 are hydrogen atoms or aliphatic radicles, are suitable for the polymerization.  In examples: (1) an internally enamelled vertical tubular vessel having a sheet metal jacket capable of being heated is filled with glass beads to which Granosil is added, and heated to 70 DEG  C. while liquid vinyl ethyl ether is introduced from a storage vessel into the top of the reaction vessel and the polymerization product is withdrawn at the bottom, the vapour of unchanged vinyl ethyl ether being returned by a reflux condenser above the reaction vessel; alternatively gaseous vinyl ethyl ether is introduced and the unchanged ether is withdrawn with the polymerization product at the bottom of the reaction vessel, separated and led in again in the vapour phase; (2) vinyl-n-butyl ether (see Specification 332,605, [Class 2 (iii), Dyes &c.], is similarly polymerized. Specification 378,544 also is referred to.