Cumene

Cumene
Names
	Preferred IUPAC name (propan-2-yl)benzene
	Other names Isopropylbenzene; Cumene (no longer recommended); Cumol; (1-methylethyl)benzene
Identifiers
CAS Number	98-82-8 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:34656 ;
ChemSpider	7128 ;
ECHA InfoCard	100.002.458
KEGG	C14396 ;
PubChem CID	7406;
RTECS number	GR8575000;
UNII	8Q54S3XE7K ;
CompTox Dashboard (EPA)	DTXSID1021827 ;
	InChI InChI=1S/C9H12/c1-8(2)9-6-4-3-5-7-9/h3-8H,1-2H3 Key: RWGFKTVRMDUZSP-UHFFFAOYSA-N ; InChI=1/C9H12/c1-8(2)9-6-4-3-5-7-9/h3-8H,1-2H3 Key: RWGFKTVRMDUZSP-UHFFFAOYAJ;
	SMILES CC(C)c1ccccc1;
Properties
Chemical formula	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)
Solubility in water	negligible
Solubility	soluble in acetone, ether, ethanol
Vapor pressure	8 mm (20°C)
Magnetic susceptibility (χ)	-89.53·10−6 cm3/mol
Refractive index (nD)	1.4915 (20 °C)
Viscosity	0.777 cP (21 °C)
Hazards
	Occupational safety and health (OHS/OSH):
Main hazards	flammable
NFPA 704 (fire diamond)	2 3 1
Flash point	43 °C (109 °F; 316 K)
Autoignition; temperature	424 °C (795 °F; 697 K)
Explosive limits	0.9-6.5%
	Lethal dose or concentration (LD, LC):
LD50 (median dose)	12750 mg/kg (oral, mouse); 1400 mg/kg (oral, rat)
LC50 (median concentration)	200 ppm (mouse, 7 hr)
LCLo (lowest published)	8000 ppm (rat, 4 hr)
	NIOSH (US health exposure limits):
PEL (Permissible)	TWA 50 ppm (245 mg/m3) [skin]
REL (Recommended)	TWA 50 ppm (245 mg/m3) [skin]
IDLH (Immediate danger)	900 ppm
Related compounds
Related compounds	ethylbenzene; toluene; benzene
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Cumene is the common name for isopropylbenzene, an organic compound that is based on an aromatic hydrocarbon with an aliphatic substitution. 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.

Production

Commercial production of cumene is by Friedel–Crafts alkylation of benzene with propylene. Cumene producers account for approximately 20% of the global demand for benzene.^[4] Previously, solid phosphoric acid (SPA) supported on alumina was used as the catalyst. Since the mid-1990s, commercial production has switched to zeolite-based catalysts.^[5] The addition of two equivalents of propylene gives diisopropylbenzene (DIPB). Using transalkylation, DIPB is comproportionated with benzene.^[6]

Safety

Isopropylbenzene forms peroxides upon contact with air. Tests for peroxides are routinely conducted before heating or distilling.

Manufacturing Processes: Many processes are available for the production of isopropyl benzene. But we discuss those processes which are most commonly used. 1. Sulphuric acid process 2. Zeolite process 3. Aluminum chloride and HCL process 4. Phosphoric acid process

2.1 - Sulphuric acid process:

           The original route for manufacturing of isopropyl benzene  was the propyl alkylation of benzene in the liquid phase using sulphuric acid as catalyst. But because of the complicated neutralization and recycle steps required, together with corrosion problems, this process has been largely replaced.

2.2 - Zeolite process:

          Two new processes using Zeolite catalyst system were developed in late 1980’s. It is based on a conventional fixed-bed system. In this process the selectivity of isopropyl benzene is generally between 70-75%. The remaining components are primarily poly isopropyl benzenes. The distillation requirement involve the separation of propane for LPG use, the recycle of excess benzene to the reaction zones, the separation of isopropyl benzene for transalkylation to cumene, and the production of a purified cumene product.

2.3 - Aluminum chloride and HCL process:

           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 dry benzene, fresh and recycled and propylene are mixed in the alkylation reaction zone with the aluminum chloride and hydrochloric acid catalyst at a temperature of less than 200-300 0C and pressure less than 0.4 MPa. The effluent from the alkylation zone is combined with recycle poly isopropyl benzene and fed to the transalkylation zone where poly isopropyl benzene is transalkylated to isopropyl benzene. The strongly acidic catalyst is separated from the organic phase by washing the reactors effluent with water and caustic.

2.4 - Phosphoric acid process:

           Currently most of the isopropyl benzene is produced commercially by using fixed-bed kieselguhr-supported phosphoric acid system developed by UOP.
           The reactants are fed as liquid from their respective storage tanks. After being pumped up to the required pressure dictated by catalyst operating conditions, reactants are mixed, vaporized and heated up to reactor operating temperature. The catalyst converts the reactants to desired and undesired products according to the reaction involved. The molar feed ratio is 2 : 1 benzene to propylene; propylene conversion is 92% per pass; the product molar selectivity ratio is 31 : 1 isopropyl benzene to DIPB. The product gas are cooled to condense essentially all of    isopropyl benzene, DIPB, and un-reacted benzene to liquid. The un-reacted propylene and propane impurity are separated from the liquid and are used as fuel gas. The liquid stream is sent to two distillation towers. The first tower separate benzene from isopropyl benzene and DIPB. The benzene purity level is 98 mol%. The second distillation tower separates isopropyl benzene from DIPB. The isopropyl benzene purity level is 99.9 mol%.

References

^ Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. pp. 139, 597. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4.
^ ^a ^b ^c ^d NIOSH Pocket Guide to Chemical Hazards. "#0159". National Institute for Occupational Safety and Health (NIOSH).
^ ^a ^b ^c "Cumene". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
^ Market Study Benzene, published by Ceresana, July 2011 [1]
^ The Innovation Group website, page accessed 15/11/07
^ "Alkylation". Kirk‐Othmer Encyclopedia of Chemical Technology. 2003. doi:10.1002/0471238961.0112112508011313.a01.pub2. {{cite encyclopedia}}: Unknown parameter |authors= ignored (help)

External links

[1] Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. pp. 139, 597. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4.

[PGCH-2] NIOSH Pocket Guide to Chemical Hazards. "#0159". National Institute for Occupational Safety and Health (NIOSH).

[IDLH-3] "Cumene". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).

[4] Market Study Benzene, published by Ceresana, July 2011 [1]

[5] The Innovation Group website, page accessed 15/11/07

[6] "Alkylation". Kirk‐Othmer Encyclopedia of Chemical Technology. 2003. doi:10.1002/0471238961.0112112508011313.a01.pub2. {{cite encyclopedia}}: Unknown parameter |authors= ignored (help)

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