Cumene (isopropylbenZl!ne) is an important chemical intermediate used for the manufacture of acetone

Cumene (isopropylbenZl!ne) is an important chemical intermediate used for the manufacture of acetone and phenol; it is produced by the catalytic alkylation of benzene with propylene. A typical crude yield from the catalytic reactor might be as shown in Table 2-1, first column. The high propane content results from the use of a mixed C J feed stream. The products require separation, and in order to hold down utilities consumption. a typical scheme would involve removal of the C J’s first. then separation of the benzene for recycle, and finally removal of the heavies from the cumene product.

Cumene (isopropylbenZl!ne) is an important chemical intermediate used for the manufacture of acetone and phenol; it is produced by the catalytic alkylation of benzene with propylene. A typical crude yield from the catalytic reactor might be as shown in Table 2-1, first column. The high propane content results from the use of a mixed C J feed stream. The products require separation, and in order to hold down utilities consumption. a typical scheme would involve removal of the C J’s first. then separation of the benzene for recycle, and finally removal of the heavies from the cumene product. The first of these steps t From Board of Registration for Professional Engineers. State of California, Examination in Chemical Engineering. November 1966; used by permission. involves a separation across a relatively wide volatility gap; hence it might be possible to employ a simple equilibrium flash-drum removal of the C 3’S rather than bringing in a more expensive fractionator at this point. Neglecting solution nonidealities and gas-law deviations and assuming the reactor effluent is flashed to 241 kPa total pressure, evaluate the flash-drum proposal by finding the percentage loss of benzene and cumene if 90 percent of the propane is to be removed in the flash operation. Vapor pressures are also shown in Table 2-1.