Editing Wax (section)

== Chemistry ==
[[File:MODOCeroline.jpg|thumb|Ceroline brand wax for floors and furniture, first half of 20th century. From the [[Museo del Objeto del Objeto]] collection.]]
Waxes are organic compounds that characteristically consist of long [[aliphatic]] [[alkyl]] chains, although aromatic compounds may also be present. Natural waxes may contain unsaturated bonds and include various [[functional group]]s such as [[carboxylic acid|fatty acids]], [[primary alcohol|primary]] and [[secondary alcohol]]s, [[ketones]], [[Aldehyde|aldehydes]] and fatty acid [[ester]]s.  Synthetic waxes often consist of [[homologous series]] of long-chain aliphatic hydrocarbons ([[alkane]]s or paraffins) that lack [[functional group]]s.<ref name=Ull/>

=== Plant and animal waxes ===
Waxes are [[biosynthesis|synthesized]] by both plants and animals.  Those of animal origin typically consist of [[wax ester]]s derived from a variety of fatty acids and carboxylic alcohols.  In waxes of plant origin, characteristic mixtures of unesterified hydrocarbons may predominate over esters.<ref name=Baker/> The composition depends not only on species, but also on geographic location of the organism.

==== Animal waxes ====
The best-known animal wax is [[beeswax]], used in constructing the [[honeycomb]]s of beehives, but other insects also secrete waxes.  A major component of beeswax is myricyl palmitate which is an [[ester]] of [[triacontanol]] and [[palmitic acid]].  Its melting point is {{Convert|62-65|C}}. [[Spermaceti]] occurs in large amounts in the head oil of the [[sperm whale]]. One of its main constituents is [[cetyl palmitate]], another ester of a [[fatty acid]] and a [[fatty alcohol]]. [[Lanolin]] is a wax obtained from wool, consisting of esters of [[sterol]]s.<ref name=Ull>Wilhelm Riemenschneider1 and Hermann M. Bolt (2005). "Esters, Organic". ''Ullmann's Encyclopedia of Industrial Chemistry''. Wiley-VCH, Weinheim. {{doi|10.1002/14356007.a09_565.pub2}}.</ref>

==== Plant waxes ====

Plants secrete waxes into and on the surface of their [[plant cuticle|cuticles]] as a way to control evaporation, wettability and hydration.<ref name=Ullmann/> The [[epicuticular wax]]es of plants are mixtures of substituted long-chain aliphatic hydrocarbons, containing alkanes, alkyl esters, fatty acids, primary and secondary alcohols, [[diol]]s, ketones and aldehydes.<ref name=Baker>EA Baker (1982) Chemistry and morphology of plant epicuticular waxes. In The Plant Cuticle. Ed. DF Cutler, KL Alvin, CE Price. Academic Press. {{ISBN|0-12-199920-3}}</ref> From the commercial perspective, the most important plant wax is [[carnauba wax]], a hard wax obtained from the Brazilian palm ''[[Copernicia prunifera]]''. Containing the ester myricyl cerotate, it has many applications, such as confectionery and other food coatings, car and furniture polish, floss coating, and [[surfboard wax]]. Other more specialized vegetable waxes include [[jojoba oil]], [[candelilla wax]] and [[ouricury wax]].

==== Modified plant and animal waxes ====
Plant and animal based waxes or oils can undergo selective chemical modifications to produce waxes with more desirable properties than are available in the unmodified starting material.<ref>{{Cite journal|last1=Floros|first1=Michael C.|last2=Raghunanan|first2=Latchmi|last3=Narine|first3=Suresh S.|date=2016-11-01|title=A toolbox for the characterization of biobased waxes|journal=European Journal of Lipid Science and Technology|volume=119|issue=6|language=en|pages=n/a|doi=10.1002/ejlt.201600360|issn=1438-9312}}</ref> This approach has relied on green chemistry approaches including olefin metathesis and enzymatic reactions and can be used to produce waxes from inexpensive starting materials like vegetable oils.<ref>{{Cite journal|last1=Schrodi|first1=Yann|last2=Ung|first2=Thay|last3=Vargas|first3=Angel|last4=Mkrtumyan|first4=Garik|last5=Lee|first5=Choon Woo|last6=Champagne|first6=Timothy M.|last7=Pederson|first7=Richard L.|last8=Hong|first8=Soon Hyeok|date=2008-08-01|title=Ruthenium Olefin Metathesis Catalysts for the Ethenolysis of Renewable Feedstocks|journal=CLEAN – Soil, Air, Water|language=en|volume=36|issue=8|pages=669–673|doi=10.1002/clen.200800088|bibcode=2008CSAW...36..669S |issn=1863-0669}}</ref><ref>{{Cite journal|last1=Petersson|first1=Anna E. V.|last2=Gustafsson|first2=Linda M.|last3=Nordblad|first3=Mathias|last4=Börjesson|first4=Pål|last5=Mattiasson|first5=Bo|last6=Adlercreutz|first6=Patrick|date=2005-11-17|title=Wax esters produced by solvent-free energy-efficient enzymatic synthesis and their applicability as wood coatings|url=http://xlink.rsc.org/?DOI=b510815b|journal=Green Chemistry|language=en|volume=7|issue=12|pages=837|doi=10.1039/b510815b|issn=1463-9270|access-date=2016-12-06|archive-date=2019-12-09|archive-url=https://web.archive.org/web/20191209163653/https://pubs.rsc.org/en/content/articlelanding/2005/GC/b510815b|url-status=live}}</ref>

=== Petroleum derived waxes ===

{{see also|Paraffin wax}}

Although many natural waxes contain esters, paraffin waxes are hydrocarbons, mixtures of alkanes usually in a [[homologous series]] of chain lengths.  These materials represent a significant fraction of petroleum. They are refined by [[vacuum distillation]]. Paraffin waxes are mixtures of saturated n- and iso- [[Alkane|alkanes]], [[naphthenes]], and [[Alkyl group|alkyl]]- and naphthene-substituted aromatic compounds. A typical alkane paraffin wax chemical composition comprises hydrocarbons with the general formula C<sub>''n''</sub>H<sub>2''n''+2</sub>, such as [[hentriacontane]], C<sub>31</sub>H<sub>64</sub>. The degree of branching has an important influence on the properties. [[Microcrystalline wax]] is a lesser produced petroleum based wax that contains higher percentage of isoparaffinic (branched) hydrocarbons and naphthenic hydrocarbons.

Millions of tons of paraffin waxes are produced annually. They are used in foods (such as chewing gum and cheese wrapping), in candles and cosmetics, as non-stick and waterproofing coatings and in polishes.

==== Montan wax ====

[[Montan wax]] is a fossilized wax extracted from coal and [[lignite]].<ref>{{Cite book|url=https://books.google.com/books?id=urFTAAAAMAAJ&q=Montan+wax+is+a+fossilized+wax+extracted+from+coal+and+lignite|title=Wax chemistry and technology|last=Ivanovsky|first=Leo|date=1952|language=en}}</ref> It is very hard, reflecting the high concentration of saturated [[fatty acid]]s and alcohols. Although dark brown and odorous, they can be purified and bleached to give commercially useful products.

==== Polyethylene and related derivatives ====

{{As of|1995}}, about 200 million kilograms of polyethylene waxes were consumed annually.<ref name=Ullmann/>

Polyethylene waxes are manufactured by one of three methods:

# The direct polymerization of ethylene, potentially including co-monomers;
# The thermal degradation of high molecular weight polyethylene resin;
# The recovery of low molecular weight fractions from high molecular weight resin production.

Each production technique generates products with slightly different properties. Key properties of low molecular weight polyethylene waxes are viscosity, density and melt point.

Polyethylene waxes produced by means of degradation or recovery from polyethylene resin streams contain very low molecular weight materials that must be removed to prevent volatilization and potential fire hazards during use. Polyethylene waxes manufactured by this method are usually stripped of low molecular weight fractions to yield a flash point >500 °F (>260 °C). Many polyethylene resin plants produce a low molecular weight stream often referred to as low polymer wax (LPW). LPW is unrefined and contains volatile oligomers, corrosive catalyst and may contain other foreign material and water. Refining of LPW to produce a polyethylene wax involves removal of oligomers and hazardous catalyst. Proper refining of LPW to produce polyethylene wax is especially important when being used in applications requiring FDA or other regulatory certification.{{Citation needed|date=March 2021}}