Production of Isobutylbenzene via The Alkylation of Toluene With Propylene

Published September 2000

Production of isobutylene involves the reaction of toluene with propylene in the presence of a sodium/potassium alloy (NaK2) catalyst. A mixture of isobutylene (IBB) and n-butylene (NBB) are produced with IBB predominating. The reaction is carried out batchwise using a mixture of fresh and recycled catalyst phase (decanted from prior run). Tarry materials produced in the reaction coat the catalyst, reduce its effectiveness and ultimately require that the catalyst phase be discarded. Under current commercial practice conditions catalyst consumption is in the order of 0.1 lb/lb IBB. The subject patent claims a novel set of operating conditions that produces no visible tarry materials and allows at least 10 consecutive batch runs before the catalyst phase has to be discarded. Catalyst consumption is less than 0.1 lb/lb IBB.

This review evaluates the potential economics of the subject technology at a base case production volume of 3.61 MM lb/yr IBB (4 MM lb/yr mixed IBB/NBB) which is sufficient to produce approximately 5 MM lb/yr ibuprofen. Plant design is based on example information disclosed in the patent and a process simulation using AspenPlus simulation software.

The subject technology is a drop-in for existing commercial production. Since the unit operations for this process design do not differ greatly from current commercial practice it is reasonable to assume, excluding catalyst costs, that the variable and direct costs for current commercial production of IBB is essentially that same as that developed in this review. On this basis and adding ROI and respective catalyst costs, Product Value for the subject technology is about half that of current commercial practice.