GB852933A - Improvements in or relating to processes involving reactions with lithium methylene and magnesium methylene - Google Patents

Abstract

Polymeric material the polymer molecules of which have a chain structure in which adjacent units are linked by a methylene group are made by bringing together at an elevated temperature (1) an organic halogen compound containing in its molecular structure a plurality of reactive halogen atoms, and (2) lithium methylene or magnesium methylene. Examples of polymers which may be made by this process include polypropylene and polyethylene made from 1, 1-dichloroethane or 1, 1-dibromoethane and methylene chloride respectively, the polymers containing some terminal halogen as impurity. Also a polymer containing benzyl units may be made from a dihalobenzene. The reaction is carried out in the absence of air and water and preferably in an inert gas atmosphere and in an inert liquid diluent, e.g. a hydrocarbon fraction or iso-octane, and may be made a continuous process. The polymers obtained consist essentially of linear chains terminating with a halogen atom which may by after-treatment be converted into a nitrile or carboxylic acid group or removed with the formation of a terminal olefinic group. Specification 778,619 is referred to.ALSO:Organic compounds, e.g. hydrocarbons and halogenated hydrocarbons, containing at least one methylene group linking two atoms in their molecular structure are prepared by bringing together at an elevated temperature (1) an organic halogen compound containing in its molecular structure at least one reactive halogen atom and (2) lithium or magnesium methylene. The product may be a linear or cyclic compound. Hydrocarbons which may be prepared include diphenyl methane from chlorobenzene, cycloparaffins such as cyclopentane and cyclohexane from a 1,4-dihalobutane and 1,5-dihalopentane respectively and a cyclopropene derivative from o-dihalobenzene. The halogen compounds used may be the bromo- or chloro-compounds. Halogenated hydrocarbons of higher molecular weight may be made from the original halogenated hydrocarbon, which may contain more than two halogen atoms in its molecular structure, by mixing the reactants in the right proportions. Thus a , o -dihalogen compounds may be made from two molar proportions of a dihalogen compound and one of the metal methylene compound. The halogen compound may be the bromo- or chloro-compound and may be an aliphatic, alicyclic or aromatic compound. The reaction is carried out in the absence of air and water and preferably in an inert gas atmosphere and in an inert liquid diluent, e.g. a hydrocarbon fraction or iso-octane. Specification 778,619 is referred to.