N-Propyl bromide
| n-Propyl bromide | |
|---|---|
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 | |
| IUPAC name 1-Bromopropane[1] | |
| Other names
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| Identifiers | |
| Abbreviations | n-PB[citation needed] |
| CAS number | 106-94-5  |
| PubChem | 7840 |
| ChemSpider | 7552  |
| EC number | 203-445-0 |
| UN number | 2344 |
| MeSH | 1-bromopropane |
| ChEMBL | CHEMBL1230095 |
| RTECS number | TX4110000 |
| Beilstein Reference | 505936 |
| Jmol-3D images | Image 1 |
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| Properties | |
| Molecular formula | C3H7Br |
| Molar mass | 122.99 g mol−1 |
| Appearance | Colorless liquid |
| Density | 1.354 g mL−1 |
| Melting point | −110.5 °C; −166.8 °F; 162.7 K |
| Boiling point | 70.3 to 71.3 °C; 158.4 to 160.2 °F; 343.4 to 344.4 K |
| Solubility in water | 2.5 g L−1 (at 20 °C) |
| Solubility in ethanol | Miscible |
| Solubility in diethyl ether | Miscible |
| log P | 2.319 |
| Vapor pressure | 19.5 kPa (at 20 °C) |
| kH | 1.4 μmol Pa−1 kg−1 |
| Refractive index (nD) | 1.43414 |
| Viscosity | 5.241 mPa s (at 20 °C) |
| Thermochemistry | |
| Std enthalpy of formation ΔfH |
−125.8–−123.0 kJ mol−1 |
| Std enthalpy of combustion ΔcH |
−2.0580–−2.0552 MJ mol−1 |
| Specific heat capacity, C | 134.6 J K−1 mol−1 |
| Hazards | |
| GHS pictograms |    |
| GHS signal word | DANGER |
| GHS hazard statements | H225, H315, H319, H335, H336, H360, H373 |
| GHS precautionary statements | P201, P210, P261, P305+351+338, P308+313 |
| EU Index | 602-019-00-5 |
| EU classification |  F  T |
| R-phrases | R60, R11, R36/37/38, R48/20, R63, R67 |
| S-phrases | S53, S45 |
| NFPA 704 |
 3
2
0
|
| Flash point | 22 °C; 72 °F; 295 K |
| Autoignition temperature | 490 °C; 914 °F; 763 K |
| Explosive limits | 4.6–?% |
| LD50 | 2.950 mg kg−1 (intraperitoneal, rat) |
| Related compounds | |
| Related alkanes | |
| (verify) (what is: /?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa) | |
| Infobox references | |
n-Propyl bromide (NPB) is an organobromine compound with the chemical formula CH3CH2CH2Br. It is a colorless liquid that is used as an solvent. It has a characteristic hydrocarbon odor.
Preparation
Industrial routes to 1-bromoalkanes involve free-radical additions to the corresponding alkenes. In this way, the anti-Markovnikov product is obtained.[2] A laboratory synthesis involves treating propanol with a mixture of hydrobromic and sulfuric acids:
- CH3CH2CH2OH + HBr → CH3CH2CH2Br + H2O
An alternate route involves refluxing propanol with phosphorus tribromide is generated in situ.[3]
Applications
Like other halocarbons, NPB finds use as a solvent. It is used for the cleaning of metal surfaces, removal of soldering residues from electronic circuit boards. It is also a solvent for adhesives. It has been deployed as a replacement for perchloroethylene as a dry cleaning solvent.[4] It is also used in the hole transport layer (HTL) of multi-layered OLEDs.
Safety
In 2013, a peer-review panel convened by the National Toxicology Program unanimously recommended that 1-bromopropane, be classified as reasonably anticipated human carcinogens[5]. In 2003, the American Conference of Governmental Industrial Hygienists (ACGIH) set the time-weighted average threshold limit value for an 8-hour exposure at 10 parts per million. Long-term exposure results in neurological damage and infertility.[6][7]
The chemical's increasing use in the 21st century resulted from need for a substitute for chlorofluorocarbons and perchloroethylene (tetrachloroethylene).[8] It has been approved for use under the U.S. EPA's Significant New Alternatives Policy (SNAP) as a suitable replacement for ozone depleting chemicals.[9]
Use of DrySolv™ Dry Cleaning Solvent, a product of Enviro Tech International[4] as a replacement for perchloroethylene may require adjustment and modification of equipment, improved ventilation and use of personal protective equipment.[8]
Health issues
Extended occupational exposure to N-Propyl bromide in higher concentrations than recommended has resulted in significant injury to workers in the United States.[6] Its use as a solvent in aerosol glues used to glue foam cushions has been especially problematic.[7] Reported symptoms to overexposure include confusion, dysarthria, dizziness, paresthesias, and ataxia; unusual fatigue and headaches, development of arthralgias, visual disturbances (difficulty focusing), paresthesias, and muscular twitching. Symptoms may persist over one year after termination of exposure.[8] Loss of feeling in the feet, an example of paresthesia, is colloquially called "dead foot" by workers who suffer from it.[7]
The U.S. EPA announced that, based on a work plan developed under the Toxic Substances Control Act of 1976, in 2013 it will begin a full risk assessment of 1-bromopropane.[10]
References
- ↑ "1-bromopropane - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 27 March 2005. Identification. Retrieved 15 June 2012.
- ↑ David Ioffe, Arieh Kampf “Bromine, Organic Compounds” in Kirk-Othmer Encyclopedia of Chemical Technology 2002 by John Wiley & Sons. doi: 10.1002/0471238961.0218151325150606.a01.
- ↑ Oliver Kamm and C. S. Marvel (1941), "Alkyl and alkylene bromides", Org. Synth.; Coll. Vol. 1: 25
- ↑ 4.0 4.1 "Technical Data Sheet". Enviro Tech International. Retrieved March 31, 2013.
- ↑ {{cite web[title=NTP Peer Reviewers Back Listing of Cumene, 1-Bromopropane in Report on Carcinogens|url=http://www.bna.com/ntp-peer-reviewers-n17179873003/|accessdate=January 29, 2014}}
- ↑ 6.0 6.1 "1-BROMOPROPANE: Human Health Effects". Hazardous Substances Data Bank. Retrieved March 31, 2013.
- ↑ 7.0 7.1 7.2 Ian Urbina (March 30, 2013). "As OSHA Emphasizes Safety, Long-Term Health Risks Fester". The New York Times. Retrieved March 31, 2013.
- ↑ 8.0 8.1 8.2 "Neurologic Illness Associated with Occupational Exposure to the Solvent 1-Bromopropane --- New Jersey and Pennsylvania, 2007--2008". Centers for Disease Control. December 5, 2008. Retrieved March 31, 2013.
- ↑ "Protection of Stratospheric Ozone: Listing of Substitutes for Ozone- Depleting Substances-n-Propyl Bromide in Solvent Cleaning". Federal Register. U.S. Environmental Protection Agency. May 30, 2007. Retrieved March 31, 2013. "This final rule lists n-propyl bromide (nPB) as an acceptable substitute when used as a solvent in industrial equipment for metals cleaning, electronics cleaning, or precision cleaning. General metals, precision, and electronics cleaning includes cleaning with industrial cleaning equipment such as vapor degreasers, in-line cleaning systems, or automated equipment used for cleaning below the boiling point."
- ↑ United States Environmental Protection Agency. "List of Chemicals for Assessment". Retrieved 23 April 2013.