Fatty alcohol#Common names

Fatty alcohols became commercially available in the early 1900s. They were originally obtained by reduction of wax esters with sodium by the Bouveault–Blanc reduction process. In the 1930s catalytic hydrogenation was commercialized, which allowed the conversion of fatty acid esters, typically tallow, to alcohols. In the 1940s and 1950s, petrochemicals became an important source of chemicals, and Karl Ziegler had discovered the polymerization of ethylene. These two developments opened the way to synthetic fatty alcohols.

Most fatty alcohols in nature are found as waxes, which are esters of fatty acids and fatty alcohols.{{Ullmann|first1=Klaus|last1=Noweck|first2=Wolfgang|last2=Grafahrend|title=Fatty Alcohols|doi=10.1002/14356007.a10_277.pub2}} They are produced by bacteria, plants and animals for purposes of buoyancy, as source of metabolic water and energy, biosonar lenses (marine mammals) and for thermal insulation in the form of waxes (in plants and insects).{{cite journal|first1=Stephen|last1=Mudge |first2=Wolfram|last2=Meier-Augenstein |first3=Charles|last3=Eadsforth |first4=Paul|last4=DeLeo|title=What contribution do detergent fatty alcohols make to sewage discharges and the marine environment?|journal=Journal of Environmental Monitoring|year=2010|pages=1846–1856|doi=10.1039/C0EM00079E |volume=12|issue=10 |pmid=20820625 }}

The traditional sources of fatty alcohols have largely been various vegetable oils, which remain a large-scale feedstock. Animal fats (tallow) were of historic importance, particularly whale oil, however they are no longer used on a large scale. Tallows produce a fairly narrow range of alcohols, predominantly C₁₆–C₁₈, while plant sources produce a wider range of alcohols (C₆–C₂₄), making them the preferred source. The alcohols are obtained from the triglycerides (fatty acid triesters), which form the bulk of the oil. The process involves the transesterification of the triglycerides to give methyl esters which are then hydrogenated to produce fatty alcohols.{{cite journal|last1=Kreutzer|first1=Udo R.|title=Manufacture of fatty alcohols based on natural fats and oils|journal=Journal of the American Oil Chemists' Society|date=February 1984|volume=61|issue=2|pages=343–348|doi=10.1007/BF02678792|s2cid=84849226}} Higher alcohols (C₂₀–C₂₂) can be obtained from rapeseed oil or mustard seed oil. Midcut alcohols are obtained from coconut oil (C₁₂–C₁₄) or palm kernel oil (C₁₆–C₁₈).

Fatty alcohols are also prepared from petrochemical sources. In the Ziegler process, ethylene is oligomerized using triethylaluminium followed by air oxidation. This process affords even-numbered alcohols:

:Al(C₂H₅)₃ + 18 C₂H₄ → Al(C₁₄H₂₉)₃

:Al(C₁₄H₂₉)₃ + {{frac|3|2}} O₂ + {{frac|3|2}} H₂O → 3 HOC₁₄H₂₉ + {{frac|1|2}} Al₂O₃

Alternatively ethylene can be oligomerized to give mixtures of alkenes, which are subjected to hydroformylation, this process affording odd-numbered aldehyde, which is subsequently hydrogenated. For example, from 1-decene, hydroformylation gives the C₁₁ alcohol:

:C₈H₁₇CH=CH₂ + H₂ + CO → C₈H₁₇CH₂CH₂CHO

:C₈H₁₇CH₂CH₂CHO + H₂ → C₈H₁₇CH₂CH₂CH₂OH

In the Shell higher olefin process, the chain-length distribution in the initial mixture of alkene oligomers is adjusted so as to more closely match market demand. Shell does this by means of an intermediate metathesis reaction.{{cite book|title=Ashford's Dictionary of Industrial Chemicals|edition=3rd|date=2011|pages=6706–6711}}{{ISBN missing}} The resultant mixture is fractionated and hydroformylated/hydrogenated in a subsequent step.

Fatty alcohols are mainly used in the production of detergents and surfactants. Due to their amphipathic nature, fatty alcohols behave as nonionic surfactants. They find use as co-emulsifiers, emollients and thickeners in cosmetics and food industry. About 50% of fatty alcohols used commercially are of natural origin, the remainder being synthetic.

Fatty alcohol are converted to their ethoxylates by treatment with ethylene oxide:{{cite book|doi=10.1002/14356007.a25_747.pub2 |chapter=Surfactants |title=Ullmann's Encyclopedia of Industrial Chemistry |date=2019 |last1=Holmberg |first1=Krister |pages=1–56 |isbn=978-3-527-30673-2 }}

:{{chem2|RCH2OH + n C2H4O -> RCH2(OCH2CH2)_{n}OH }}

The resulting fatty alcohol ethoxylates are important surfactants.

Another large class of surfactants is that of the sodium alkyl sulfates such as sodium dodecyl sulfate (SDS). Five million tons of SDS and related materials are produced annually by sulfation of dodecyl alcohol and related fatty alcohols.

The metabolism of fatty alcohols is impaired in several inherited human peroxisomal disorders, including adrenoleukodystrophy and Sjögren–Larsson syndrome.{{cite journal|first1=James L.|last1=Hargrove|first2=Phillip|last2=Greenspan|first3=Diane K.|last3=Hartle|date=2004|title=Nutritional Significance and Metabolism of Very Long Chain Fatty Alcohols and Acids from Dietary Waxes|journal=Exp. Biol. Med. (Maywood) |volume=229|issue=3|pages=215–226|doi=10.1177/153537020422900301|pmid=14988513|s2cid=38905297}}

Fatty alcohols are relatively benign materials, with LD₅₀ (oral, rat) ranging from 3.1–4 g/kg for hexanol to 6–8 g/kg for octadecanol. For a 50 kg person, these values translate to more than 100 g. Tests of acute and repeated exposures have revealed a low level of toxicity from inhalation, oral or dermal exposure of fatty alcohols. Fatty alcohols are not very volatile and the acute lethal concentration is greater than the saturated vapor pressure. Longer-chain (C₁₂–C₁₆) fatty alcohols produce fewer health effects than short-chain (smaller than C₁₂). Short-chain fatty alcohols are considered eye irritants, while long chain alcohols are not.{{cite journal|last1=Veenstra|first1=Gauke|first2=Catherine|last2=Webb|first3=Hans|last3=Sanderson|first4=Scott E.|last4=Belanger|first5=Peter|last5=Fisk|first6=Allen|last6=Nielson|first7=Yutaka|last7=Kasai|first8=Andreas|last8=Willing|first9=Scott|last9=Dyer|first10=David|last10=Penney|first11=Hans|last11=Certa|first12=Kathleen|last12=Stanton|first13=Richard|last13=Sedlak|title=Human health risk assessment of long chain alcohols|journal=Ecotoxicology and Environmental Safety|volume=72|issue=4|year=2009|url=https://pure.au.dk/portal/en/publications/human-health-risk-assessment-of-long-chain-alcohols-lcoh(0656c100-20d3-11dd-be51-000ea68e967b).html|issn=0147-6513|pages=1016–1030|doi=10.1016/j.ecoenv.2008.07.012|pmid=19237197|bibcode=2009EcoES..72.1016V |url-access=subscription}} Fatty alcohols exhibit no skin sensitization.{{cite web|last=UK/ICCA|title=SIDS Initial Assessment Profile|work=OECD Existing Chemicals Database|url=http://webnet.oecd.org/hpv/UI/handler.axd?id=03441f78-d135-4cab-b832-edfb1d0d677e|year=2006}}

Repeated exposure to fatty alcohols produce low-level toxicity and certain compounds in this category can cause local irritation on contact or low-grade liver effects (essentially linear alcohols have a slightly higher rate of occurrence of these effects). No effects on the central nervous system have been seen with inhalation and oral exposure. Tests of repeated bolus dosages of 1-hexanol and 1-octanol showed potential for CNS depression and induced respiratory distress. No potential for peripheral neuropathy has been found. In rats, the no observed adverse effect level (NOAEL) ranges from 200 mg/kg/day to 1000 mg/kg/day by ingestion. There has been no evidence that fatty alcohols are mutagenic or cause reproductive toxicity or infertility. Fatty alcohols are effectively eliminated from the body when exposed, limiting possibility of retention or bioaccumulation.

Margins of exposure resulting from consumer uses of these chemicals are adequate for the protection of human health as determined by the Organisation for Economic Co-operation and Development (OECD) high production volume chemicals program.{{cite journal|last1=Sanderson|first1=Hans |first2=Scott E.|last2= Belanger |first3=Peter R.|last3= Fisk |first4=Christoph|last4= Schäfers |first5=Gauke |last5=Veenstra |first6=Allen M. |last6=Nielsen |first7=Yutaka|last7= Kasai |first8=Andreas |last8=Willing |first9=Scott D.|last9= Dyer |first10=Kathleen|last10= Stanton |first11=Richard|last11= Sedlak|title=An overview of hazard and risk assessment of the OECD high production volume chemical category—Long chain alcohols [C₆–C₂₂] (LCOH)|journal=Ecotoxicology and Environmental Safety|date=May 2009|volume=72|issue=4|pages=973–979|doi=10.1016/j.ecoenv.2008.10.006|pmid=19038453 |bibcode=2009EcoES..72..973S }}

Fatty alcohols up to chain length C₁₈ are biodegradable, with length up to C₁₆ biodegrading within 10 days completely. Chains C₁₆ to C₁₈ were found to biodegrade in rates ranging from 62% to 76% in 10 days. Chains greater than C₁₈ were found to degrade by 37% in 10 days. Field studies at wastewater treatment plants have shown that 99% of fatty alcohols of lengths C₁₂–C₁₈ are removed.

Fate prediction using fugacity modeling has shown that fatty alcohols with chain lengths of C₁₀ and greater in water partition into sediment. Lengths C₁₄ and above are predicted to stay in the air upon release. Modeling shows that each type of fatty alcohol will respond independently upon environmental release.

Fish, invertebrates and algae experience similar levels of toxicity with fatty alcohols although it is dependent on chain length with the shorter chain having greater toxicity potential. Longer chain lengths show no toxicity to aquatic organisms.

This category of chemicals was evaluated under the Organisation for Economic Co-operation and Development (OECD) high production volume chemicals program. No unacceptable environmental risks were identified.

This table lists some alkyl alcohols. Note that in general the alcohols with even numbers of carbon atoms have common names, since they are found in nature, whereas those with odd numbers of carbon atoms generally do not have a common name.

{{Reflist}}

• {{cite web | url=http://www.cyberlipid.org/simple/simp0003.htm | title=Fatty Alcohols and Aldehydes | author=Cyberlipid | access-date=2007-02-06 | archive-url=https://web.archive.org/web/20120625155634/http://www.cyberlipid.org/simple/simp0003.htm | archive-date=2012-06-25 | url-status=dead }} General overview of fatty alcohols, with references.
• {{cite web

| url= http://www.zenitech.com/documents/new%20pdfs/articles/All%20about%20fatty%20alcohols%20Condea.pdf

| title= Dr. Z Presents All about fatty alcohols

| author= CONDEA

| access-date= 2007-02-06

| archive-url= https://web.archive.org/web/20070927230034/http://www.zenitech.com/documents/new%20pdfs/articles/All%20about%20fatty%20alcohols%20Condea.pdf

| archive-date= 2007-09-27

| url-status= dead

}}

{{Alcohols}}

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Category:Lipids

Category:Commodity chemicals

Category:Primary alcohols