Editing Creosote (section)

===Wood-tar creosote===
{| style="background:#F9F9F9; border:1px solid #AAA; padding:5px; float:right; margin-left:20px;"
|
{| style="font-size:12px; text-align:right;"
|+ style="text-align:left; padding-left:5px; padding-bottom:10px; font-size:13.5px;" | Constituency of distillations of creosote from different woods at different temperatures<ref name=allen353/><ref name=apa1073/><ref name=rcs294/>
! scope="col" style="font-size:13px;" |
! scope="col" colspan="2" style="font-size:13px; padding-left:20px; text-align:center; border-bottom:1px solid #AAA;" | [[Beech]]
! scope="col" style="font-size:13px; padding-left:20px; text-align:center; border-bottom:1px solid #AAA;" | [[Oak]]
! scope="col" style="font-size:13px; padding-left:20px; text-align:center; border-bottom:1px solid #AAA;" | [[Pine]]
|-
! scope="row" style="font-size:11px;" |
! scope="col" style="padding-left:20px;" | 200&ndash;220&nbsp;°C
! scope="col" style="padding-left:20px;" | 200&ndash;210&nbsp;°C
! scope="col" style="padding-left:20px;" | 200&ndash;210&nbsp;°C
! scope="col" style="padding-left:20px;" | 200&ndash;210&nbsp;°C
|-
! scope="row" style="text-align:left;" | [[Monophenols]]
| 39.0 %|| 39.0 %|| 55.0 %|| 40.0%
|-
! scope="row" style="text-align:left;" | [[Guaiacol]]
| 19.7 %|| 26.5 %|| 14.0 %|| 20.3%
|-
! scope="row" style="text-align:left;" | [[Creosol]] and [[Homologous series|homologs]]
| 40.0% || 32.1% || 31.0% || 37.5%
|-
! scope="row" style="text-align:left;" | Loss
| 1.3% || 2.4% || . . . || 2.2%
|-
|}
|}
Wood-tar creosote is a colourless to yellowish greasy liquid with a smoky odor, produces a sooty flame when burned, and has a burned taste. It is non-buoyant in water, with a [[specific gravity]] of 1.037 to 1.087, retains fluidity at a very low temperature, and boils at 205-225&nbsp;°C. In its purest form, it is transparent. Dissolution in water requires up to 200 times the amount of water as the base creosote.<ref name=nickels614/> This creosote is a combination of natural [[phenols]]: primarily [[guaiacol]] and [[creosol]] (4-methylguaiacol), which typically constitutes 50% of the oil; second in prevalence are [[cresol]] and [[xylenol]]; the rest being a combination of [[monophenols]] and [[polyphenol]]s.
{| style="background:#F9F9F9; border:1px solid #AAA; padding:5px; float:left; margin-right:20px;"
|
{| class="sortable" style="font-size:12px; text-align:right;"
|+ style="text-align:left; padding-left:5px; padding-bottom:10px; font-size:13.5px;" | Composition of a typical beech-tar creosote<ref name=allen353/><ref name=lee1483/>
! class="unsortable" style="text-align:left; padding-right:20px;" |
| class="unsortable" |
|
|-
! class="unsortable" style="text-align:left; padding-right:20px;" | [[Phenol]]
| class="unsortable" style="text-align:left; padding-right:20px;" | {{chem2|C6H5OH}}
| 5.2%
|-
! class="unsortable" style="text-align:left; padding-right:20px;" | [[o-Cresol]]
| class="unsortable" style="text-align:left; padding-right:20px;" | {{chem2|(CH3)C6H4(OH)}}
| 10.4%
|-
! class="unsortable" style="text-align:left; padding-right:20px;" | [[m-Cresol]] and [[p-cresol]]
| class="unsortable" style="text-align:left; padding-right:20px;" | {{chem2|(CH3)C6H4(OH)}}
| 11.6%
|-
! class="unsortable" style="text-align:left; padding-right:20px;" | [[2-Ethylphenol]]
| class="unsortable" style="text-align:left; padding-right:20px;" | {{chem2|C6H4(C2H5)OH}}
| 3.6%
|-
! class="unsortable" style="text-align:left; padding-right:20px;" | [[Guaiacol]]
| class="unsortable" style="text-align:left; padding-right:20px;" | {{chem2|C6H4(OH)(OCH3)}}
| 25.0%
|-
! class="unsortable" style="text-align:left; padding-right:20px;" | 3,4-[[Xylenol]]
| class="unsortable" style="text-align:left; padding-right:20px;" | {{chem2|C6H3(CH3)2OH}}
| 2.0%
|-
! class="unsortable" style="text-align:left; padding-right:20px;" | [[3,5-Xylenol]]
| class="unsortable" style="text-align:left; padding-right:20px;" | {{chem2|C6H3(CH3)2OH}}
| 1.0%
|-
! class="unsortable" style="text-align:left; padding-right:20px;" | Various phenols
| class="unsortable" style="text-align:left; padding-right:20px;" | {{chem2|C6H5OH}}&mdash;
| 6.2%
|-
! class="unsortable" style="text-align:left; padding-right:20px;" | [[Creosol]] and [[Homologous series|homologs]]
| class="unsortable" style="text-align:left; padding-right:20px;" | {{chem2|C6H3(CH3)(OH)(OCH3)}}&mdash;
| 35.0%
|-
|}
|}
The simple phenols are not the only active element in wood-tar creosote. In solution, they [[coagulation|coagulate]] [[albumin]], which is a water-soluble protein found in meat, so they serve as a preserving agent, but also cause denaturation. Most of the phenols in the creosote are [[methoxy]] derivatives: they contain the [[methoxy group]] {{chem2|(\sO\sCH3)}} linked to the [[benzene]] nucleus. The high level of methyl derivates created from the action of heat on wood (also apparent in the methyl alcohol produced through distillation) make wood-tar creosote substantially different from coal-tar creosote. Guaiacol is a [[methyl group|methyl]] [[ether]] of [[pyrocatechin]], while creosol is a methyl ether of methyl-pyrocatechin, the next [[Homologous series|homolog]] of pyrocatechin. Methyl ethers differ from simple phenols in being less hydrophilic, caustic, and poisonous.<ref name=psgb468/> This allows meat to be successfully preserved without tissue denaturation, and allows creosote to be used as a medical ointment.<ref name=allen348/>
{| style="background:#F9F9F9; border:1px solid #AAA; padding:5px; float:right; margin-left:20px;"
|
{| style="font-size:12px; text-align:left;"
|+ style="text-align:left; padding-left:5px; padding-bottom:10px; font-size:13.5px;" | Derivation of wood-tar creosote from resinous woods<ref name=overton13/>
|
[[File:Derivation of wood-tar creosote.svg|frameless|upright=1.5]]
|}
|}
Because wood-tar creosote is used for its guaiacol and creosol content, it is generally derived from [[beech tree|beechwood]] rather than other woods, since it distills with a higher proportion of those chemicals to other phenolics. The creosote can be obtained by distilling the wood tar and treating the fraction heavier than water with a sodium hydroxide solution. The alkaline solution is then separated from the insoluble oily layer, boiled in contact with air to reduce impurities, and decomposed by diluted sulfuric acid. This produces a crude creosote, which is purified by re-solution in alkali, re-precipitation with acid, then redistilled with the fraction passing over between 200° and 225° constituting the purified creosote.<ref name=allen347/>

When ferric chloride is added to a dilute solution, it will turn green: a characteristic of ortho-oxy derivatives of benzene.<ref name=psgb468/> It dissolves in sulfuric acid to a red liquid, which slowly changes to purple-violet. Shaken with hydrochloric acid in the absence of air, it becomes red, the color changing in the presence of air to dark brown or black.<ref name=allen348/>

In preparation of food by [[smoking (food)|smoking]], [[guaiacol]] contributes mainly to the smoky [[taste]], while the dimethyl ether of [[pyrogallol]], [[syringol]], is the main chemical responsible for the smoky [[aroma]].

====Historical uses====

=====Industrial=====
Soon after it was discovered and recognized as the principle of meat smoking, wood-tar creosote became used as a replacement for the process. Several methods were used to apply the creosote. One was to dip the meat in pyroligneous acid or a water of diluted creosote, as Reichenbach did, or brush it over with them, and within one hour the meat would have the same quality of that of traditionally smoked preparations.<ref name=abel23/> Sometimes the creosote was diluted in vinegar rather than water, as vinegar was also used as a preservative.<ref name=letheby225/> Another was to place the meat in a closed box, and place with it a few drops of creosote in a small bottle. Because of the volatility of the creosote, the atmosphere was filled with a vapour containing it, and it would cover the flesh.<ref name=abel23/>

The application of wood tar to seagoing vessels was practiced through the 18th century and early 19th century, before the creosote was isolated as a compound. Wood-tar creosote was found not to be as effective in wood treatments, because it was harder to infuse the creosote into the wood cells, but still experiments<ref name=joerin767/> were done, including by many governments, because it proved to be less expensive on the market.<ref name=bradbury107/>

=====Medical=====
Even before creosote as a chemical compound was discovered, it was the chief active component of medicinal remedies in different cultures around the world.

In antiquity, pitches and resins were used commonly as medicines. [[Pliny the Elder|Pliny]] mentions a variety of tar-like substances being used as medicine, including ''cedria'' and ''pissinum''.<ref name=cormack58/> ''Cedria'' was the pitch and resin of the cedar tree, being equivalent to the oil of tar and pyroligneous acid which are used in the first stage of distilling creosote.<ref name=parr383/><ref name=pliny8/> He recommends cedria to ease the pain in a toothache, as an injection in the ear in case of hardness of hearing, to kill parasitic worms, as a preventive for infusion, as a treatment for [[phthiriasis]] and [[wikt:porrigo|porrigo]], as an antidote for the poison of the [[sea hare]], as a liniment for [[elephantiasis]], and as an ointment to treat [[ulcer]]s both on the skin and in the lungs.<ref name=pliny8/> He further speaks of cedria being used as the embalming agent for preparing mummies.<ref name=cormack58/> ''Pissinum'' was a tar water that was made by boiling cedria, spreading wool fleeces over the vessels to catch the steam, and then wringing them out.<ref name=berkeley9/><ref name=pliny290/>

[[File:John Smibert - Bishop George Berkeley - Google Art Project.jpg|thumb|left|upright|Portrait of [[George Berkeley|Bishop Berkeley]] by [[John Smybert]], 1727]]
The ''Pharmacopée de Lyon'', published in 1778, says that cedar tree oil is believed to cure vomiting and help medicate tumors and ulcers.<ref name=cormack59/><ref name=vitet427/> Physicians contemporary to the discovery of creosote recommended ointments and pills made from tar or pitch to treat skin diseases.<ref name=cormack59/> [[Tar water]] had been used as a folk remedy since the Middle Ages to treat affections like dyspepsia. [[George Berkeley|Bishop Berkeley]] wrote several works on the medical virtues of tar water, including a philosophical work in 1744 titled ''Siris: a chain of philosophical reflexions and inquiries concerning the virtues of tar water, and divers other subjects connected together and arising one from another'', and a poem where he praised its virtues.<ref name=cd300/> Pyroligneous acid was also used at the time in a medicinal water called ''Aqua Binelli'' (Binelli's water),<ref name=cormack59/> a compound which its inventor, the Italian Fedele Binelli, claimed to have [[Hemostasis|hemostatic]] properties in his research published in 1797.{{sfn|Tsiamis |Sgantzou |Popoti |Papavramidou |2020}} These claims have since been disproven.{{sfn|Tsiamis |Sgantzou |Popoti |Papavramidou |2020}}{{sfn|Simon|1833}}{{sfn|Dunglison|1846|pp=64–65}}

Given this history, and the antiseptic properties known to creosote, it became popular among physicians in the 19th century. A dilution of creosote in water was sold in pharmacies as ''Aqua creosoti'', as suggested by the previous use of pyroligneous acid. It was prescribed to quell the irritability of the stomach and bowels and detoxify, treat ulcers and abscesses, neutralize bad odors, and stimulate the mucous tissues of the mouth and throat.<ref name=king617/><ref name=taylor207/> Creosote in general was listed as an [[irritation|irritant]], [[styptic]], [[antiseptic]], [[narcotic]], and [[diuretic]], and in small doses when taken internally as a [[sedative]] and [[anaesthetic]]. It was used to treat ulcers, and as a way to sterilize the tooth and deaden the pain in case of a tooth-ache.<ref name=king617/>

Creosote was suggested as a treatment for tuberculosis by Reichenbach as early as 1833. Following Reichenbach, it was argued for by [[John Elliotson]] and Sir [[John Rose Cormack]].<ref name=king617/> Elliotson, inspired by the use of creosote to arrest vomiting during an outbreak of [[cholera]], suggested its use for tuberculosis through inhalation. He also suggested it for epilepsy, neuralgia, diabetes, and chronic [[glanders]].<ref name=whittaker77/> The idea of using it for tuberculosis failed to be accepted. Use for this purpose was dropped, until the idea was revived in 1876 by British doctor [[G. Anderson Imlay]], who suggested it be applied locally by spray to the bronchial mucous membrane.<ref name=king617/><ref name=imlay514/><ref name=dobbell315/> This was followed up in 1877 when it was argued for in a clinical paper by [[Charles-Joseph Bouchard|Charles Bouchard]] and [[Henri Gimbert]].<ref name=kinnicut514/> Germ theory had been established by [[Louis Pasteur|Pasteur]] in 1860, and Bouchard, arguing that a [[bacillus]] was responsible for the disease, sought to rehabilitate creosote for its use as an antiseptic to treat it. He began a series of trials with Gimbert to convince the scientific community, and claimed a promising cure rate.<ref name=contrepois211/> A number of publications in Germany confirmed his results in the following years.<ref name=kinnicut514/>

Later, a period of experimentation with different techniques and chemicals using creosote in treating tuberculosis lasted until about 1910, when radiation therapy seemed more promising. Guaiacol, instead of a full creosote solution, was suggested by [[Hermann Sahli]] in 1887. He argued it had the active chemical of creosote and had the advantage of being of definite composition and having a less unpleasant taste and odor.<ref name=kinnicut515/> A number of solutions of both creosote and guaiacol appeared on the market, such as ''phosphotal'' and ''guaicophosphal'', phosphites of creosote and guaiacol; ''eosot'' and ''geosot'', valerinates of creosote and guaicol; ''phosot'' and ''taphosot'', phosphate and tannophospate of creosote; and ''creosotal'' and ''tanosal'', tannates of creosote.<ref name=coblentz/> Creosote and eucalyptus oil were also a remedy used together, administered through a vaporizor and inhaler. Since then, more effective and safer treatments for tuberculosis have been developed.

In the 1940s, Canadian-based [[Eldon Boyd]] experimented with guaiacol and a recent synthetic modification—glycerol guaiacolate ([[guaifenesin]])—on animals. His data showed that both drugs were effective in increasing secretions into the airways in laboratory animals, when high-enough doses were given.{{citation needed|date=August 2020}}

====Current uses====

=====Industrial=====
Wood-tar creosote is to some extent used for [[wood preservation]], but it is generally mixed with coal-tar creosote, since the former is not as effective. Commercially available preparations of "[[liquid smoke]]", marketed to add a smoked flavour to meat and aid as a preservative, consist primarily of creosote and other constituents of smoke.<ref name=chenoweth206/> Creosote is the ingredient that gives liquid smoke its function; guaicol lends to the taste and the creosote oils help act as the preservative. Creosote can be destroyed by treatment with chlorine, either [[sodium hypochlorite]], or [[calcium hypochlorite]] solutions. The phenol ring is essentially opened, and the molecule is then subject to normal digestion and normal respiration.{{Citation needed|date=August 2019}}

=====Medical=====
The [[guaifenesin]] developed by Eldon Boyd is still commonly used today as an [[expectorant]], sold over the counter, and usually taken by mouth to assist the bringing up of phlegm from the airways in acute respiratory tract infections. Guaifenesin is a component of [[Mucinex]], [[Robitussin DAC]], [[Cheratussin DAC]], [[Robitussin AC]], [[Cheratussin AC]], [[Benylin]], [[DayQuil]] Mucous Control, Meltus, and Bidex 400.{{Citation needed|date=September 2021}}

[[Seirogan]] is a popular [[Kampo]] medicine in Japan, used as an anti-diarrheal, and has 133&nbsp;mg wood creosote from beech, pine, maple or oak wood per adult dose as its primary ingredient. Seirogan was first used as a gastrointestinal medication by the Imperial Japanese Army in Russia during the [[Russo-Japanese War]] of 1904 to 1905.<ref name=seirogan/>

[[Creomulsion]] is a cough medicine in the United States, introduced in 1925, that is still sold and contains beechwood creosote. Beechwood creosote is also found under the name ''kreosotum'' or ''kreosote''.