GB918739A - Ozonization of dihydro-pyran compounds, the products therefrom, and the production of amino-acids therefrom - Google Patents

Abstract

Ethylene, propylene, styrene, acrylates, methacrylates and like monomers are polymerized utilizing ozonization products of 3 3,4-dihydro-1,2-pyran-2-carboxylic acid and salts and esters thereof as polymerization initiators. Specification 866,391 is referred to.ALSO:The invention comprises the ozonization product of 3 : 4-dihydro-1 : 2-pyran-2-carboxylic acid or a salt or ester thereof, which contains active oxygen and does not undergo violent decomposition when subjected to thermal or mechanical shock. The products, presumably ozonides, are prepared by passing an ozone containing gas through an ozone-inert solvent solution of the acid, as a salt thereof e.g. an alkali metal, magnesium, calcium, ammonium or substituted ammonium salt, or an ester thereof e.g. an alkyl, aryl, aralkyl or heterocyclic ester thereof. The reaction may be effected at -75 DEG to +75 DEG C. in, as solvent, water, a lower fatty acid, a lower aliphatic alcohol or ester thereof, a hydrocarbon or a halogenated hydrocarbon. The ozonization products may be used as polymerization initiators (see Group IV(a)). The ozonization products may be converted into hydroxy glutaric acid or a salt, ester or lactone thereof, or mixtures thereof by reaction with water to effect cleavage thereof and simultaneously or successively with an oxidising agent to effect partial oxidation thereof. Cleavage is preferably effected with water containing an acidic substance at elevated temperature. The partial oxidation may be carried out with air, oxygen containing if desired a small amount of ozone, hydrogen peroxide, cupric oxide, a hypochlorite, oxides of nitrogen or potassium permanganate. Hydroxy glutaric acid and/or its lactone may be isolated from the product. Preferably, however, the product is reacted with ammonia at an elevated temperature to form the ammonium salt of pyrrolidone carboxylic acid. This reaction may be effected at 250 DEG -350 DEG C. in a sealed vessel. The resulting pyrrolidone carboxylic acid may be converted into DL-glutamic acid by hydrolysis. Examples describe the ozonization of the dihydropyran carboxylic acid, its sodium salt and ethyl ester and conversion of the product into DL-glutamic acid as above specified. The dihydropyran carboxylic acid is prepared by oxidation of acrolein dimers, stabilized by oxalic acid, following the procedure described in Specification 866,391.