such as formaldehyde acetaldehyde propionaldehyde butyraldehyde and n valeraldehyde and alkyl halides such as methyl chloride ethyl chloride the propyl chlorides the butyl chlorides and the pentyl chlorides and so forth mixtures of light olefins can also be useful as alkylating agents in the alkylation process of this invention accordingly mixtures of ethylene propylene butenes and or pentenes which are major constituents of a variety of refinery streams e g fuel gas gas plant off gas containing ethylene propylene etc naphtha cracker off gas containing light olefins refinery fcc propane propylene streams etc are useful alkylating agents herein typical aromatic alkylation reactions which may be improved by the present invention include obtaining ethylbenzene from the reaction of benzene with ethylene cumene from the reaction of benzene with propylene ethyltoluene from the reaction of toluene with ethylene and cymenes from the reaction of toluene with propylene the alkylation process of this invention is conducted such that the organic reactants i e the alkylatable aromatic compound and the alkylating agent are brought into contact with an alkylation catalyst in a suitable reaction zone such as for example in a flow reactor containing a fixed bed of the catalyst composition under effective alkylation conditions such conditions include a temperature of from about 0 u00b0 c to about 500 u00b0 c and preferably between about 50 u00b0 c and about 250 u00b0 c a pressure of from about 0 2 to about 250 atmospheres and preferably from about 5 to about 100 atmospheres a molar ratio of alkylatable aromatic.