An acrylamide of the general formula CH2=CR1CONH2, wherein R1 is hydrogen or a saturated hydrocarbon group of not more than eight carbon atoms, is prepared by a vapour phase process characterized by passing a lower alkoxy amide of the general formula ROCH2CHR1CONH2, wherein R is a saturated hydrocarbon group of not more than eight carbon atoms and R1 is hydrogen or a saturated hydrocarbon of not more than eight carbon atoms, over lithium phosphate or titania as a catalyst maintained at a temperature of 225 DEG to 500 DEG C. If desired, the catalyst may be supported on a carrier such as silica and the converter containing the catalyst may be a length of stainless steel tube, the inlet end of which may be packed with an inert material, e.g. catalytically inert silica, to serve as a preheater or vaporizer for the starting material. A diluent may be employed, e.g. nitrogen or vapour of low boiling liquid such as water or an alkanol. A polymerization inhibitor may be present during the reaction, e.g. N-phenyl-b -naphthylamine, and if the acrylamide is isolated by distillation an inhibitor should be present, e.g. N,N1-di-(b -naphthyl) paraphenylene-diamine. In examples: (1) and (2) acrylamide is obtained by passing b -methoxypropionamide, methanol and N-phenyl-b -naphthylamine, preheated over catalytically inert silica, over heated lithium phosphate, cooling and condensing the products and after addition of di-b -naphthylparaphenylenediamine fractionating under reduced pressure; (3) methacrylamide is similarly obtained using b -methoxyisobutyramide; (4) acrylamide is obtained from b -methoxy-propionamide using titania as catalyst. Processes for the preparation of acrylamide and its homologues referred to include the reaction of ammonia and amines with acrylyl chloride or b -chloropropionyl chloride followed by dehydrochlorination or with b -propiolactone followed by dehydration, the cracking of dimethylamine from b -dimethylamino N-(orthotolyl) propionamide to form N-(orthotolyl) acrylamide and pyrolysis of N,N-dimethyl-a -acetoxypropionamide to give dimethylacrylamide.