Chloromethane

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Chloromethane
Natta projection of chloromethane.svg
Ball and stick model of chloromethane Chloromethane-3D-balls.png
Ball and stick model of chloromethane
Spacefill model of chloromethane Chloromethane-3D-vdW.png
Spacefill model of chloromethane
Names
Preferred IUPAC name
Chloromethane [1]
Other names
  • Refrigerant-40
  • R-40 [2]
  • Methyl chloride [2]
  • Monochloromethane [2]
Identifiers
3D model (JSmol)
1696839
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.000.744 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 200-817-4
24898
KEGG
MeSH Methyl+Chloride
PubChem CID
RTECS number
  • PA6300000
UNII
UN number 1063
  • InChI=1S/CH3Cl/c1-2/h1H3 Yes check.svgY
    Key: NEHMKBQYUWJMIP-UHFFFAOYSA-N Yes check.svgY
  • CCl
Properties
CH3Cl
Molar mass 50.49 g·mol−1
AppearanceColorless gas
Odor Faint, sweet odor [3]
Density 1.003 g/mL (-23.8 °C, liquid) [2] 2.3065 g/L (0 °C, gas) [2]
Melting point −97.4 °C (−143.3 °F; 175.8 K) [2]
Boiling point −23.8 °C (−10.8 °F; 249.3 K) [2]
5.325 g L−1
log P 1.113
Vapor pressure 506.09 kPa (at 20 °C (68 °F))
940 nmol Pa−1 kg−1
-32.0·10−6 cm3/mol
Structure
Tetragonal
Tetrahedron
1.9 D
Thermochemistry
Std molar
entropy (S⦵298)
234.36 J K−1 mol−1
−83.68 kJ mol−1
−764.5–−763.5 kJ mol−1
Hazards
GHS labelling:
GHS-pictogram-flamme.svg GHS-pictogram-silhouette.svg
Danger
H220, H351, H373
P210, P281, P410+P403
NFPA 704 (fire diamond)
NFPA 704.svgHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 4: Will rapidly or completely vaporize at normal atmospheric pressure and temperature, or is readily dispersed in air and will burn readily. Flash point below 23 °C (73 °F). E.g. propaneInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
2
4
0
Flash point −20 °C (−4 °F; 253 K) [2]
625 °C (1,157 °F; 898 K) [2]
Explosive limits 8.1%-17.4% [3]
Lethal dose or concentration (LD, LC):
150-180 mg/kg (oral, rat) [2]
5.3 mg/L/4 h (inhalation, rat) [2]
72,000 ppm (rat, 30 min)
2200 ppm (mouse, 6 hr)
2760 ppm (mammal, 4 hr)
2524 ppm (rat, 4 hr) [4]
20,000 ppm (guinea pig, 2 hr)
14,661 ppm (dog, 6 hr) [4]
NIOSH (US health exposure limits):
PEL (Permissible)
TWA 100 ppm C 200 ppm 300 ppm (5-minute maximum peak in any 3 hours) [3]
REL (Recommended)
Ca [3]
IDLH (Immediate danger)
Ca [2000 ppm] [3]
Related compounds
Related alkanes
Related compounds
 2-Chloroethanol
Supplementary data page
Chloromethane (data page)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)

Chloromethane, also called methyl chloride, Refrigerant-40, R-40 or HCC 40, is an organic compound with the chemical formula CH3Cl. One of the haloalkanes, it is a colorless, sweet-smelling, flammable gas. Methyl chloride is a crucial reagent in industrial chemistry, although it is rarely present in consumer products, [5] and was formerly utilized as a refrigerant. Most chloromethane is biogenic.

Contents

Occurrence

Chloromethane is an abundant organohalogen, anthropogenic or natural, in the atmosphere. Natural sources produce an estimated 4,100,000,000 kg/yr. [6]

Marine

Laboratory cultures of marine phytoplankton (Phaeodactylum tricornutum, Phaeocystis sp., Thalassiosira weissflogii, Chaetoceros calcitrans, Isochrysis sp., Porphyridium sp., Synechococcus sp., Tetraselmis sp., Prorocentrum sp., and Emiliana huxleyi) produce CH3Cl, but in relatively insignificant amounts. [7] [8] An extensive study of 30 species of polar macroalgae revealed the release of significant amounts of CH3Cl in only Gigartina skottsbergii and Gymnogongrus antarcticus. [9]

Biogenesis

The salt marsh plant Batis maritima contains the enzyme methyl chloride transferase that catalyzes the synthesis of CH3Cl from S-adenosine-L-methionine and chloride. [10] This protein has been purified and expressed in E. coli , and seems to be present in other organisms such as white rot fungi ( Phellinus pomaceus ), red algae ( Endocladia muricata ), and the ice plant ( Mesembryanthemum crystallinum ), each of which is a known CH3Cl producer. [10] [11]

Sugarcane and the emission of methyl chloride

In the sugarcane industry, the organic waste is usually burned in the power cogeneration process. When contaminated by chloride, this waste burns, releasing methyl chloride in the atmosphere. [12]

Interstellar detections

Chloromethane has been detected in the low-mass Class 0 protostellar binary, IRAS 16293–2422, using the Atacama Large Millimeter Array (ALMA). It was also detected in the comet 67P/Churyumov–Gerasimenko (67P/C-G) using the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) instrument on the Rosetta spacecraft. [13] The detections reveal that chloromethane can be formed in star-forming regions before planets or life is formed.[ citation needed ]

Chloromethane has been detected in space. ALMA and Rosetta Detect Freon-40 in Space.jpg
Chloromethane has been detected in space.

Production

Chloromethane was first synthesized by the French chemists Jean-Baptiste Dumas and Eugene Peligot in 1835 by boiling a mixture of methanol, sulfuric acid, and sodium chloride. This method is the forerunner for that used today, which uses hydrogen chloride instead of sulfuric acid and sodium chloride. [15]

Chloromethane is produced commercially by treating methanol with hydrochloric acid or hydrogen chloride, according to the chemical equation: [5]

CH3OH + HCl → CH3Cl + H2O

A smaller amount of chloromethane is produced by treating a mixture of methane with chlorine at elevated temperatures. This method, however, also produces more highly chlorinated compounds such as dichloromethane, chloroform, and carbon tetrachloride. For this reason, methane chlorination is usually only practiced when these other products are also desired. This chlorination method also cogenerates hydrogen chloride, which poses a disposal problem. [5]

CH4 + Cl2 → CH3Cl + HCl
CH3Cl + Cl2 → CH2Cl2 + HCl
CH2Cl2 + Cl2 → CHCl3 + HCl
CHCl3 + Cl2 → CCl4 + HCl

Dispersion in the environment

CH3Cl measured by the Advanced Global Atmospheric Gases Experiment (AGAGE) in the lower atmosphere (troposphere) at stations around the world. Abundances are given as pollution free monthly mean mole fractions in parts-per-trillion. CH3Cl mm.png
CH3Cl measured by the Advanced Global Atmospheric Gases Experiment (AGAGE) in the lower atmosphere (troposphere) at stations around the world. Abundances are given as pollution free monthly mean mole fractions in parts-per-trillion.

Most of the methyl chloride present in the environment ends up being released to the atmosphere. After being released into the air, the atmospheric lifetime of this substance is about 10 months with multiple natural sinks, such as ocean, transport to the stratosphere, soil, etc. [16] [17] [18]

On the other hand, when the methyl chloride emitted is released to water, it will be rapidly lost by volatilization. The half-life of this substance in terms of volatilization in the river, lagoon and lake is 2.1 h, 25 h and 18 days, respectively. [19] [20]

The amount of methyl chloride in the stratosphere is estimated to be 2 x 106 tonnes per year, representing 20-25% of the total amount of chlorine that is emitted to the stratosphere annually. [21] [22]

Uses

Large scale use of chloromethane is for the production of dimethyldichlorosilane and related organosilicon compounds. [5] These compounds arise via the direct process. The relevant reactions are (Me = CH3):

x MeCl + Si → Me3SiCl, Me2SiCl2, MeSiCl3, Me4Si2Cl2, ...

Dimethyldichlorosilane (Me2SiCl2) is of particular value as a precursor to silicones, but trimethylsilyl chloride (Me3SiCl) and methyltrichlorosilane (MeSiCl3) are also valuable. Smaller quantities are used as a solvent in the manufacture of butyl rubber and in petroleum refining.

Chloromethane is employed as a methylating and chlorinating agent, e.g. the production of methylcellulose. It is also used in a variety of other fields: as an extractant for greases, oils, and resins, as a propellant and blowing agent in polystyrene foam production, as a local anesthetic, as an intermediate in drug manufacturing, as a catalyst carrier in low-temperature polymerization, as a fluid for thermometric and thermostatic equipment, and as a herbicide.

Obsolete applications

Chloromethane was a widely used refrigerant, but its use has been discontinued. It was particularly dangerous among the common refrigerants of the 1930s due to its combination of toxicity, flammability and lack of odor as compared with other toxic refrigerants such as sulfur dioxide and ammonia. [23] Chloromethane was also once used for producing lead-based gasoline additives (tetramethyllead).

Safety

Inhalation of chloromethane gas produces central nervous system effects similar to alcohol intoxication. The TLV is 50 ppm and the MAC is the same. Prolonged exposure may have mutagenic effects. [5]

See also

Related Research Articles

<span class="mw-page-title-main">Chlorine</span> Chemical element, symbol Cl and atomic number 17

Chlorine is a chemical element; it has symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine is a yellow-green gas at room temperature. It is an extremely reactive element and a strong oxidising agent: among the elements, it has the highest electron affinity and the third-highest electronegativity on the revised Pauling scale, behind only oxygen and fluorine.

<span class="mw-page-title-main">Haloalkane</span> Group of chemical compounds derived from alkanes containing one or more halogens

The haloalkanes are alkanes containing one or more halogen substituents. They are a subset of the general class of halocarbons, although the distinction is not often made. Haloalkanes are widely used commercially. They are used as flame retardants, fire extinguishants, refrigerants, propellants, solvents, and pharmaceuticals. Subsequent to the widespread use in commerce, many halocarbons have also been shown to be serious pollutants and toxins. For example, the chlorofluorocarbons have been shown to lead to ozone depletion. Methyl bromide is a controversial fumigant. Only haloalkanes that contain chlorine, bromine, and iodine are a threat to the ozone layer, but fluorinated volatile haloalkanes in theory may have activity as greenhouse gases. Methyl iodide, a naturally occurring substance, however, does not have ozone-depleting properties and the United States Environmental Protection Agency has designated the compound a non-ozone layer depleter. For more information, see Halomethane. Haloalkane or alkyl halides are the compounds which have the general formula "RX" where R is an alkyl or substituted alkyl group and X is a halogen.

Chloroform, or trichloromethane, is an organic compound with the formula CHCl3 and a common solvent. It is a very volatile, colorless, strong-smelling, dense liquid produced on a large scale as a precursor to refrigerants and PTFE. Chloroform is a trihalomethane that serves as a powerful anesthetic, euphoriant, anxiolytic, and sedative when inhaled or ingested. Chloroform was used as an anesthetic between the 19th century and the first half of the 20th century. It is miscible with many solvents but it is only very slightly soluble in water.

The compound hydrogen chloride has the chemical formula HCl and as such is a hydrogen halide. At room temperature, it is a colorless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric water vapor. Hydrogen chloride gas and hydrochloric acid are important in technology and industry. Hydrochloric acid, the aqueous solution of hydrogen chloride, is also commonly given the formula HCl.

<span class="mw-page-title-main">Carbon tetrachloride</span> Chemical compound

Carbon tetrachloride, also known by many other names (such as carbon tet for short and tetrachloromethane, also recognised by the IUPAC) is a chemical compound with the chemical formula CCl4. It is a non-flammable, dense, colourless liquid with a "sweet" chloroform-like odour that can be detected at low levels. It was formerly widely used in fire extinguishers, as a precursor to refrigerants and as a cleaning agent, but has since been phased out because of environmental and safety concerns. Exposure to high concentrations of carbon tetrachloride can affect the central nervous system and degenerate the liver and kidneys. Prolonged exposure can be fatal.

<span class="mw-page-title-main">Tetrachloroethylene</span> Chemical compound in very wide use

Tetrachloroethylene, also known under the systematic name tetrachloroethene, or perchloroethylene, and abbreviations such as "perc", and "PCE", is a chlorocarbon with the formula Cl2C=CCl2. It is a colorless liquid widely used for dry cleaning of fabrics, hence it is sometimes called "dry-cleaning fluid". It also has its uses as an effective automotive brake cleaner. It has a mild sweet, sharp odor, detectable by most people at a concentration of 50 ppm.

<span class="mw-page-title-main">Dichloromethane</span> Chemical compound

Dichloromethane is an organochlorine compound with the formula CH2Cl2. This colorless, volatile liquid with a chloroform-like, sweet odor is widely used as a solvent. Although it is not miscible with water, it is slightly polar, and miscible with many organic solvents.

<span class="mw-page-title-main">1,1,1-Trichloroethane</span> Solvent, now banned for ozone depletion

The organic compound 1,1,1-trichloroethane, also known as methyl chloroform and chlorothene, is a chloroalkane with the chemical formula CH3CCl3. It is an isomer of 1,1,2-trichloroethane. This colorless, sweet-smelling liquid was once produced industrially in large quantities for use as a solvent. It is regulated by the Montreal Protocol as an ozone-depleting substance and its use is being rapidly phased out.

In chemistry, halogenation is a chemical reaction that entails the introduction of one or more halogens into a compound. Halide-containing compounds are pervasive, making this type of transformation important, e.g. in the production of polymers, drugs. This kind of conversion is in fact so common that a comprehensive overview is challenging. This article mainly deals with halogenation using elemental halogens. Halides are also commonly introduced using salts of the halides and halogen acids. Many specialized reagents exist for and introducing halogens into diverse substrates, e.g. thionyl chloride.

<span class="mw-page-title-main">Halomethane</span> Halogen compounds derived from methane

Halomethane compounds are derivatives of methane with one or more of the hydrogen atoms replaced with halogen atoms. Halomethanes are both naturally occurring, especially in marine environments, and human-made, most notably as refrigerants, solvents, propellants, and fumigants. Many, including the chlorofluorocarbons, have attracted wide attention because they become active when exposed to ultraviolet light found at high altitudes and destroy the Earth's protective ozone layer.

Organochlorine chemistry is concerned with the properties of organochlorine compounds, or organochlorides, organic compounds containing at least one covalently bonded atom of chlorine. The chloroalkane class includes common examples. The wide structural variety and divergent chemical properties of organochlorides lead to a broad range of names, applications, and properties. Organochlorine compounds have wide use in many applications, though some are of profound environmental concern, with TCDD being one of the most notorious.

<span class="mw-page-title-main">Manganese(II) chloride</span> Chemical compound

Manganese(II) chloride is the dichloride salt of manganese, MnCl2. This inorganic chemical exists in the anhydrous form, as well as the dihydrate (MnCl2·2H2O) and tetrahydrate (MnCl2·4H2O), with the tetrahydrate being the most common form. Like many Mn(II) species, these salts are pink, with the paleness of the color being characteristic of transition metal complexes with high spin d5 configurations.

In chemistry, trihalomethanes (THMs) are chemical compounds in which three of the four hydrogen atoms of methane are replaced by halogen atoms. Trihalomethanes with all the same halogen atoms are called haloforms. Many trihalomethanes find uses in industry as solvents or refrigerants. Some THMs are also environmental pollutants, and few are considered carcinogenic.

Trichlorofluoromethane, also called freon-11, CFC-11, or R-11, is a chlorofluorocarbon (CFC). It is a colorless, faintly ethereal, and sweetish-smelling liquid that boils around room temperature. CFC-11 is a Class 1 ozone-depleting substance which allegedly damages Earth's protective stratospheric ozone layer.

<span class="mw-page-title-main">Phosphorus pentachloride</span> Chemical compound

Phosphorus pentachloride is the chemical compound with the formula PCl5. It is one of the most important phosphorus chlorides/oxychlorides, others being PCl3 and POCl3. PCl5 finds use as a chlorinating reagent. It is a colourless, water-sensitive solid, although commercial samples can be yellowish and contaminated with hydrogen chloride.

The chemical compound 1,2-dichloroethane, commonly known as ethylene dichloride (EDC), is a chlorinated hydrocarbon. It is a colourless liquid with a chloroform-like odour. The most common use of 1,2-dichloroethane is in the production of vinyl chloride, which is used to make polyvinyl chloride (PVC) pipes, furniture and automobile upholstery, wall coverings, housewares, and automobile parts. 1,2-Dichloroethane is also used generally as an intermediate for other organic chemical compounds, and as a solvent. It forms azeotropes with many other solvents, including water and other chlorocarbons.

<span class="mw-page-title-main">Antimony pentachloride</span> Chemical compound

Antimony pentachloride is a chemical compound with the formula SbCl5. It is a colourless oil, but typical samples are yellowish due to dissolved chlorine. Owing to its tendency to hydrolyse to hydrochloric acid, SbCl5 is a highly corrosive substance and must be stored in glass or PTFE containers.

<span class="mw-page-title-main">Disulfur dichloride</span> Chemical compound

Disulfur dichloride is the inorganic compound of sulfur and chlorine with the formula S2Cl2. It is an amber oily liquid.

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Methyl halide transferase is an enzyme with systematic name S-adenosylmethionine:iodide methyltransferase. This enzyme catalyses the following chemical reaction

References

  1. ↑ International Union of Pure and Applied Chemistry (2014). Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013. The Royal Society of Chemistry. p. 1033. doi:10.1039/9781849733069. ISBN   978-0-85404-182-4.
  2. 1 2 3 4 5 6 7 8 9 10 11 Record in the GESTIS Substance Database of the Institute for Occupational Safety and Health
  3. 1 2 3 4 5 NIOSH Pocket Guide to Chemical Hazards. "#0403". National Institute for Occupational Safety and Health (NIOSH).
  4. 1 2 "Methyl chloride". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  5. 1 2 3 4 5 Rossberg, M.; Lendle, W.; Pfleiderer, G.; Tögel, A.; Dreher, E. L.; Langer, E.; Rassaerts, H.; Kleinschmidt, P.; Strack (2006). "Chlorinated Hydrocarbons". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a06_233.pub2. ISBN   978-3527306732.
  6. ↑ Gribble, Gordon (2023). Kinghorn, A. Douglas.; Falk, Heinz; Gibbons, Simon; Asakawa, Yoshinori; Liu, Ji-Kai; Dirsch, Verena M. (eds.). Naturally Occurring Organohalogen Compounds. Progress in the Chemistry of Organic Natural Products. Switzerland: Springer Nature. ISBN   3-031-26629-3.
  7. ↑ Scarratt MG, Moore RM (1996). "Production of Methyl Chloride and Methyl Bromide in Laboratory Cultures of Marine Phytoplankton". Mar Chem. 54 (3–4): 263–272. Bibcode:1996MarCh..54..263S. doi:10.1016/0304-4203(96)00036-9.
  8. ↑ Scarratt MG, Moore RM (1998). "Production of Methyl Bromide and Methyl Chloride in Laboratory Cultures of Marine Phytoplankton II". Mar Chem. 59 (3–4): 311–320. Bibcode:1998MarCh..59..311S. doi:10.1016/S0304-4203(97)00092-3.
  9. ↑ Laturnus F (2001). "Marine Macroalgae in Polar Regions as Natural Sources for Volatile Organohalogens". Environ Sci Pollut Res. 8 (2): 103–108. doi:10.1007/BF02987302. PMID   11400635. S2CID   570389.
  10. 1 2 Ni X, Hager LP (1998). "cDNA Cloning of Batis maritima Methyl Chloride Transferase and Purification of the Enzyme". Proc Natl Acad Sci USA. 95 (22): 12866–71. Bibcode:1998PNAS...9512866N. doi: 10.1073/pnas.95.22.12866 . PMC   23635 . PMID   9789006.
  11. ↑ Ni X, Hager LP (1999). "Expression of Batis maritima Methyl Chloride Transferase in Escherichia coli". Proc Natl Acad Sci USA. 96 (7): 3611–5. Bibcode:1999PNAS...96.3611N. doi: 10.1073/pnas.96.7.3611 . PMC   22342 . PMID   10097085.
  12. ↑ Lobert, Jurgen; Keene, Willian; Yevich, Jennifer (1999). "Global chlorine emissions from biomass burning: Reactive Chlorine Emissions Inventory". Journal of Geophysical Research: Atmospheres. 104 (D7): 8373–8389. Bibcode:1999JGR...104.8373L. doi: 10.1029/1998JD100077 .
  13. ↑ "ALMA and Rosetta Detect Freon-40 in Space".
  14. ↑ "ALMA and Rosetta Detect Freon-40 in Space - Dashing Hopes that Molecule May be Marker of Life". eso.org. Retrieved 3 October 2017.
  15. ↑ "Chloromethane". American Chemical Society. Retrieved 2022-05-13.
  16. ↑ Fabian P, Borchers R, Leifer R, Subbaraya BH, Lal S, Boy M (1996). "Global stratospheric distribution of halocarbons". Atmospheric Environment. 30 (10/11): 1787–1796. Bibcode:1996AtmEn..30.1787F. doi:10.1016/1352-2310(95)00387-8.
  17. ↑ Zhang W, Jiao Y, Zhu R, Rhew RC (2020). "Methyl Chloride and Methyl Bromide Production and Consumption in Coastal Antarctic Tundra Soils Subject to Sea Animal Activities". Environmental Science & Technology. 54 (20): 13354–13363. Bibcode:2020EnST...5413354Z. doi:10.1021/acs.est.0c04257. PMID   32935983. S2CID   221745138.
  18. ↑ Carpenter LJ, Reimann S, Burkholder JB, Clerbaux C, Hall BD, Hossaini R, Laube JC, Yvon-Lewis SA (2014). "Update on ODSs and Other Gases of Interest to the Montreal Protocol". WMO (World Meteorological Organization), Scientific Assessment of Ozone Depletion: 2014, Global Ozone Research and Monitoring Project.
  19. ↑ Lyman, Warren; Rosenblatt, David; Reehl, William (1982). Handbook of chemical property estimation methods . McGraw-Hill. ISBN   9780070391758.
  20. ↑ Agency for Toxic Substances and Disease Registry (1990). Toxicological profile for chloromethane.
  21. ↑ Borchers R, Gunawardena R, Rasmussen RA (1994). "Long term trend of selected halogenated hydrocarbons". Ozone in the Troposphere and Stratosphere. NASA: 259–262. 19950004240.
  22. ↑ Crutzen PJ, Gidel LT (1983). "The tropospheric budgets of the anthropogenic chlorocarbons CO, CH4, CH3Cl and the effect of various NOx sources on tropospheric ozone". Journal of Geophysical Research. 88: 6641–6661. doi:10.1029/JC088iC11p06641.
  23. ↑ https://archive.org/details/sim_consumer-reports_1936-07_1_3/page/5/mode/1up Consumers Union Reports, Vol. 1, No. 3, July 1936, p. 5.
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