Alkylaromatics Production

A process for alkylation or transalkylation of an alkylatable aromatic compound having reactive impurities with an alkylating agent to produce a monoalkylated aromatic compound, comprising the steps of:

• (a) providing a guard bed having a first molecular sieve catalyst located upstream of a reaction zone;
• (b) contacting at least a portion of said alkylatable aromatic compounds, and at least a portion of said alkylating agent with a first molecular sieve catalyst in said guard bed under suitable conditions to remove said reactive impurities and form a first effluent comprising monoalkylated aromatic compound, unreacted alkylatable aromatic compounds and unreacted alkylating agent;
• (c) contacting said first effluent with a second molecular sieve catalyst different from said first molecular sieve catalyst in said reaction zone under suitable alkylation or transalkylation conditions to produce additional said monoalkylated aromatic compounds, said suitable alkylation or transalkylation conditions comprise a water content in a range from about 1 wppm to about 10 wt. % based on the combined weight of said alkylatable aromatic compound and said alkylating agent;
• and
• (d) maintaining said water content in said range in said reaction zone for the majority of the on-oil time;
• wherein the cycle length of said second molecular sieve catalyst operated inside said water content range is greater than the cycle length of said second molecular sieve catalyst operated outside said water content range when said reaction zone is operated under equivalent alkylation or transalkylation conditions.