Cumene Names Preferred IUPAC name Other names Identifiers 1236613 ChEBI ChEMBL ChemSpider ECHA InfoCard 100.002.458 EC Number KEGG RTECS number UNII UN number 1918 Properties C9H12 Molar mass 120.195 g·mol−1 Appearance Colorless liquid Odor Sharp, gasoline-like Density 0.862 g cm−3, liquid Melting point −96 °C (−141 °F; 177 K) Boiling point 152 °C (306 °F; 425 K) negligible Solubility soluble in acetone, ether, ethanol Vapor pressure 4.5 mmHg (25 °C)[2] −89.53·10−6 cm3/mol 1.4915 (20 °C) Viscosity 0.777 cP (21 °C) Hazards Occupational safety and health (OHS/OSH): flammable GHS labelling: Warning H226, H302, H304, H312, H314, H332, H335, H341, H412, H441 P201, P202, P260, P261, P264, P270, P271, P273, P280, P281, P301+P312, P301+P330+P331, P302+P352, P303+P361+P353, P304+P312, P304+P340, P305+P351+P338, P308+P313, P310, P312, P321, P322, P330, P363, P405, P501 NFPA 704 (fire diamond) Flash point 43 °C (109 °F; 316 K) 424 °C (795 °F; 697 K) Explosive limits 0.9-6.5% Lethal dose or concentration (LD, LC): 12750 mg/kg (oral, mouse) 1400 mg/kg (oral, rat)[4] 200 ppm (mouse, 7 hr)[4] 8000 ppm (rat, 4 hr)[4] NIOSH (US health exposure limits): TWA 50 ppm (245 mg/m3) [skin][3] TWA 50 ppm (245 mg/m3) [skin][3] 900 ppm[3] Related compounds ethylbenzenetoluenebenzene
Cumene (isopropylbenzene) is an organic compound that contains a benzene ring with an isopropyl substituent. It is a constituent of crude oil and refined fuels. It is a flammable colorless liquid that has a boiling point of 152 °C. Nearly all the cumene that is produced as a pure compound on an industrial scale is converted to cumene hydroperoxide, which is an intermediate in the synthesis of other industrially important chemicals, primarily phenol and acetone (known as the cumene process).
Commercial production of cumene is by Friedel-Crafts alkylation of benzene with propylene. The original route for manufacturing of cumene was by alkylation of benzene in the liquid phase using sulfuric acid as a catalyst, but because of the complicated neutralization and recycling steps required, together with corrosion problems, this process has been largely replaced. As an alternative, solid phosphoric acid (SPA) supported on alumina has been used as the catalyst.
Since the mid-1990s, commercial production has switched to zeolite-based catalysts. In this process, the efficiency of cumene production is generally 70-75%. The remaining components are primarily polyisopropyl benzenes. In 1976, an improved cumene process that uses aluminum chloride as a catalyst was developed. The overall conversion of cumene for this process can be as high as 90%.
The addition of two equivalents of propylene gives diisopropylbenzene (DIPB). Using transalkylation, DIPB is comproportionated with benzene to give cumene.[5]
Depending on the conditions, autoxidation of cumene gives dicumyl peroxide or cumene hydroperoxide. Both reactions exploit the weakness of the tertiary C-H bond. The tendency of cumene to form peroxides by autoxidation poses safety concerns.[6] Tests for peroxides are routinely conducted before heating or distilling.
Cumene is frequently found as an ingredient in thread locking fluids.[7][8] Cumene is also a precursor chemical to the herbicide isoproturon.[9]
- Pseudocumene
- National Pollutant Inventory – Cumene fact sheet
- Cumene Production from Benzene and Propylene Using Aluminum Chloride Catalyst