Conversion of vinylbenzenes to ethynylbenzenes

Abstract

Abstract CHLORINATION OF VINYLBENZENES LEADS TO A MIXTURE OF PRODUCTS RATHER THAN ONLY THE A,B-DICHLROETHYL DERIVATIVES, THE EXPECTED PRODUCTS. IN CONTRAST, BROMINE PRODUCES ONLY THE EXPECTED A,B-DIBROMOETHYL DERIVATIVES. WHEN THE MIXTURE OF CHLORINATED PRODUCTS IS DEHYDROHALOGENATED WITH MOST OF THE DEHYDROHALOGENATING AGENTS FOUND USEFUL FOR THE DEHYDROBROMINATION OF THE BROMINATED PRODUCTS, A LOWER YIELD OF THE CORRESPONDING ETHYNYL COMPOUNDS OR ONLY PARTIALLY DEHYDROCHLORINATED PRODUCTS ARE OBTAINED WITH CONSIDERABLE AMOUNTS OF CHLORINATED PRODUCTS REMAINING UNCONVERTED BECAUSE OF THEIR NONREACTIVITY WITH THE DEHYDROHALOGENATING AGENTS. HOWEVER, IT HAS BEEN FOUND THAT ALKALI METAL AMIDES ARE CAPABLE OF COMPLETELY DEHYDROCHLORINATING THE MIXTURE OF CHLORINATED PRODUCTS TO THE DESIRED ETHYNYL COMPOUNDS. THIS PERMITS LOW COST CHLORINE TO BE SUBSTITUTED FOR THE MORE EXPENSIVE BROMINE AND PROVIDES AN ECONOMICAL PROCESS FOR CONVERTING VINYLBENZENES TO THE CORRESPONDING ETHYNYLBENZENES WITHOUT THE PRODUCTION OF UNDERSIRED BY-PRODUCTS. THE ACETYLENE PRODUCTS ARE USEFUL IN MAKING POLYACETYLENES.

Inventors

• 👤 Howard M Relles

Bibliographic Details