Talk:Alcohol

Contents

1 Toxicity 2 Water 3 pH of Alcohols 4 Etymology 5 Link suggestions 6 New chemistry section 7 Major rewrite

Toxicity

Why are alcohols toxic, what do they do to the body? AxelBoldt 04:50 Sep 10, 2002 (UTC)

In low amounts alcohols are not toxic. But in moderate to high amounts taken over short time periods they can be toxic. Alcohols (esp. ethanol) is quickly absorbed into the bloodstream and reaches the brain where it interferes with synaptic firing and causes the death of brain cells by changing the electrochemical properties around cells (intracellular calcium is increased which weakens the electrochemical gradient across the cell's membrane -- cells, esp. neurons, die without this gradient -- which is vital to the operation of membrane pumps and channels). There is also direct damage to cell membranes from free-radicals that are produced from alcohol metabolism.

The liver produces a special enzyme (alcohol dehydrogenase) that breaks down alcohols into acetaldehyde which is turned into acetic acid (another enzyme takes the acid and turns it into fatty acid, CO2 and water -- these are mostly deposited locally which leads to "beer bellies"). Chronic drinkers, however, so tax this metabolic pathway that things go awry; fatty acids build up as plaques in the capilaries around liver cells and those cells begin to die. This is the cause of cirrhosis of the liver. The liver is part of the body's filtration system and if it is damaged then certain toxins build up -- this leads to symptoms of jaundice. --mav

I wonder if most of this would fit better in ethanol, or does it apply to all alcohols? AxelBoldt 15:05 Sep 10, 2002 (UTC)

It is my understanding that all alcohols would have similar effects, but I think you are right anyway since the only onw that is really consumed in any quantity is ethanol. --mav

In fact, alcohols are toxic to organic cells in nearly whatever amount, but it's not much of a problem for human beings except in "moderate to high amounts taken over short time periods". - Centrx 20:41, 3 Jan 2005 (UTC)

I believe that a large part of methanol's toxicity comes from the formaldehyde metabolite Evand 04:52, 25 Apr 2005 (UTC)

Water

Is water itself an alcohol according to the chemical/physical definition of an alcohol? Stan 10:29, 26 Feb 2004 (UTC)

The definition given on the alcohol page is:

In chemistry, an alcohol is an organic compound in which a hydroxyl group (-OH) is bound to a carbon atom, which in turn is bound to other hydrogen and/or carbon atoms; in other words, alcohol is characterized by one or more hydroxyl (OH) groups attached to a carbon atom of an alkyl group (hydrocarbon chain).

If I alter that slightly to:

An alcohol is a compound in which a hydroxyl group (-OH) is bound to zero or more carbon atom, which in turn is bound to other hydrogen and/or carbon atoms; in other words, alcohol is characterized by one or more hydroxyl (OH) groups attached to a carbon atom of an alkyl group (hydrocarbon chain), or just to a hydrogen atom.

then under this definition H-OH, i.e. water, would be the simplest alcohol.

What I've done it take out In chemistry on the preumption that perhaps in physics the definition is slightly different. What I'd be interested is to know whether water's physical characteristics can be equated to the series of alcohols ordered by the number of carbon atoms starting at zero, i.e.

H-OH CH3-OH C2H5-OH C4H9-OH and so on.

They're all colorless liquids for a start.

Matt Stan 19:24, 10 Mar 2004 (UTC)

An interesting idea, though I strongly doubt that physics would use a different definition of alcohol than chemistry (which as every physicist knows is just sub-field of physics).

Anyway, some numbers, in the order you specified (H2O, CH3OH, C2H5OH, C4H9OH, C5H11OH):

Density (g/cm3): 1.00, 0.79, 0.79, 0.80, 0.81, 0.82

Melting point (K): 273, 175, 159, 146, 184, 194

Boiling point (K): 373, 337, 351, 370, 390, 411

Water fairly clearly bucks the trend. -- DrBob 19:45, 10 Mar 2004 (UTC)

It should be noted that water is most definitely *NOT* an alcohol, making the "zero or more carbons," revised definition like calling an orange an apple, for experiment's sake. It's entirely inane: simply containing the hydroxyl group does not make a compound an alcohol, and the trend broken above was to be expected. It is that carbon that has been omitted from the revised definition which is essential to the alcoholic character.

An alcohol is characterized by one or more hydroxyl (OH) groups attached to the carbon atom of alkyl groups of a hydrocarbon.

pH of Alcohols

In my understanding (and from what I've been taught at my Chemistry courses), Alcohols are not acids, rather bases, and when dissolved in water raise the amount of -OH ions

They also cancel out acids in reactions with them, since the -OH from alcohol bonds with the hydrogen from acids to form water.

Would that be correct?

Since no real chemist bothered to answer: As said in the article, "alcohols are weakly acidic, even less acidic than water". That is sort of like like saying "Jews are weakly Muslim, even less Muslim than Christians". 8-) So I suppose that your fist sentence is correct...

I won't hazard an opinion on your second sentence. IIRC, that reaction does not hapen readily in water solutions, which is where "acid" and "base" have their traditional meaning. It may happen in dry reactions but then I guess that it is a bond-swapping thing, without ionization involved. But chemists have invented some weird definitions of acid and base since I went through college...
Jorge Stolfi 06:36, 15 Jun 2004 (UTC)

Alcohols can indeed be either weakly acidic or basic, just like water. They have a pKa of around 16-19, which means that in the presence of a strong base such as NaH or NaNH₂ they will form alkoxide salts (e.g., ROH + NaH -> RO- Na+). However in the presence of a strong acid such as sulfuric acid they will protonate, for example ROH + H⁺ --> ROH₂⁺

However the OH in alcohols is not free hydroxide ion, so it does not react in a simple way with acids to form water the way sodium hydroxide does. Alcohols will NEVER raise the amount of -OH ions in water, they are neutral if tested with pH paper.

Walkerma 22:14, 11 Mar 2005 (UTC)

Etymology

((begin text from Talk:Al-Razi Jorge Stolfi 03:33, 15 Jun 2004 (UTC)))

As for the etymology, I have always heard that "alcohol" came from al-ghoul="spirit" which also gave the star "Algol" and the English "ghoul. this page (http://www.websters-dictionary-online.org/definition/english/gh/ghoul.html) about "ghoul" gives the Arabic translation as "غول=(alcohol, bogey, goblin, hobgoblin, ogre)".

For what its worth. The word "Ghawl" غول is mentioned in the Qur'an 37:47 in reference to wine. The context is that wine in Paradise will be different and "Free from Gawl; nor will they suffer intoxication therefrom." Gawl is translated as "headiness", but I have seen it translated as "the stuff that makes wine intoxicating = alcohol". -- KB 16:32, 2004 Jun 13 (UTC)

Jorge Stolfi 03:13, 13 Jun 2004 (UTC)

Well, there must be something wrong with my ears. I cannot find a single source can find only a couple of sources for al-ghoul -> alcohol, all of them the others have the al-kuhul story. It sounds pretty weird, but... Jorge Stolfi 03:39, 13 Jun 2004 (UTC)

Merriam Webster and other sources on Etimology (http://dictionary.reference.com/search?q=alcohol) are wrong about al-kuhul being powdered antimony. What they are referring to is الكحل which is indeed a black powder used medicinally (antiseptic?) and cosmetically (eye liner) from old times (and still is), and commonly used in early Islamic times. Alcohol is كحول which is spelled differently. The inability of some Western writers to understand the consonental system of Semitic language and distinguish Semitic short vowels and long vowels have caused much confusion. -- KB 16:32, 2004 Jun 13 (UTC)

This document (http://www.dlcas.com/Training/AlcoholtheChemical.pdf) confirms Al-Razi as the discoverer but says that the "al-ghoul"="the devil" etymology was invented by an US anti-alcohol movement for propaganda purposes.
Jorge Stolfi 04:27, 13 Jun 2004 (UTC)

Don't you just love Wikipedia! What a great place it is to reach beyond the limitations of stuffy authoritative sources and test their accuracy! I read all the above references (except the Qur'an, as I don't know Arabic) to get to the bottom of this question. (By the way, please use a descriptive term for the displayed text of a link, rather than "this document" or "other sources". I will repeat some of the above links as needed so it's easier for someone reading this later to know what they're clicking on before they click.)

Both the al-ghoul (Webster's Dictionary Online, "ghoul" (http://www.websters-dictionary-online.org/definition/english/gh/ghoul.html)) or al-kohl (Kevin Scheel's "Alcohol the Chemical" paper, p. 8, 1st full paragraph (http://www.dlcas.com/Training/AlcoholtheChemical.pdf)) and the al-kuhul (Webster's Dictionary Online "Word Origin" entry from American Heritage (http://www.websters-dictionary-online.org/definition/english/gh/ghoul.html)) arguments have plausibility, although the "spirit" version seems more likely, as KB argues. Unfortunately, Scheel's paper doesn't provide references for his assertions. (Incidentally, Scheel states [p. 9, last paragraph] that it was the Temperance Movement — a political movement primarily consisting of women, often actively opposed to the US government — who used the al-ghul "spirit" interpretation to demonize alcohol.)

The "antimony powder" argument makes use of a broadening of the concept of ore refinement into distillation, as practiced in European countries with Latin-influenced languages. This is not at all unusual in etymology. But etymology is more art than science, especially considering the relative dearth of written materials many centuries old, from which etymology derives its understanding of changing languages. It's easy to see how European scholarship would miss the significance of Arabic sources, but the same parochial view in the general population would encourage a belief in a non-Arabic transmutation of "alkuhul". It's even possible that the parallel changes (European powder->refinement->distallation and Arabic ghost->infused spirit->drink) reinforced each other through the ages. In any case, I'd say one cannot accept the "antimony" derivation at face value without more documentation, and any such research should include an assessment of the Arabic derivation to have any credibility.

I would suggest that further discussion of this intriguing topic be moved either to Wikipedia's "alcohol" article or, better yet, Wiktionary's entry (http://en.wiktionary.org/wiki/Alcohol), which doesn't even have a definition yet, let alone a proper etymology! -- Jeff Q 20:01, 13 Jun 2004 (UTC)

P.S. Please forgive the reformatting of your above comments, JS and KB, but both old and new Wiki styles use colons to provide visual separation of Talk page comments. Using bullets for separation tends to make dialogs hard to read, especially as comments often include bulleted or numbered lists. Also, one shouldn't insert one's comments between two pieces of a single posting (or between the text and the signature) because it makes it hard to tell who said what later on. -- Jeff Q 20:01, 13 Jun 2004 (UTC)

I must apologize for misreading Jorge Stolfi's mention of the US movement propagandizing the Arabic "spirit" derivation. I thought he'd said it was a government movement, but clearly he did not say that. -- Jeff Q 20:07, 13 Jun 2004 (UTC)

Wow, thanks for the research! Jorge Stolfi 02:18, 14 Jun 2004 (UTC)

((end text from Talk:Al-Razi))

Thank you, Jorge Stolfi and KB! You folks did all the research. ☺ All I did was read it, summarize it, and comment. -- Jeff Q 03:49, 15 Jun 2004 (UTC)

Nice etymology write-up in the article, JS! I inserted some spaces in your Arabic-to-English sequences because, at least in the current Monobook sans-serif font and to this non-Arabic reader's eye, it's hard to distinguish between Arabic script and the equals sign, so the Roman-character transliteration looks jammed up against the Arabic. Thanks again for your work. -- Jeff Q 05:17, 15 Jun 2004 (UTC)

Jorge, I've been trying to fill in the Hebrew reference, but I've only found the following:

ןומיטנא = antimon (antimun?)

which sounds like a modern word for antimony — probably not the Biblical reference, presumably for stibnite ore. Where did you come up with the Hebrew connection? Do you know where in the Hebrew Bible stibnite is mentioned? Also, I found a reference to a "Mesopotamian name for eye-paint, guhlu, usually translated as stibium powder… [which] passed into Arabic as kuhl". It mentions no period or specific language or people. -- Jeff Q 07:53, 15 Jun 2004 (UTC)

Jeffq, I have to leave now, but I found these references to "stibio" in the Latin Vulgate:

Jeremiah 4:30 tu autem vastata quid facies cum vestieris te coccino cum ornata fueris monili aureo et pinxeris stibio oculos tuos frustra conponeris contempserunt te amatores tui animam tuam quaerent

Ezekiel 23:40 miserunt ad viros venientes de longe ad quos nuntium miserant itaque ecce venerunt quibus te lavisti et circumlevisti stibio oculos tuos et ornata es mundo muliebri

2Kings 9:30 venit Hieu Hiezrahel porro Hiezabel introitu eius audito depinxit oculos suos stibio et ornavit caput suum et respexit per fenestram

Hope it helps...

BTW, from those quotes it would seems that kohl in Israel was a fairly late imported "perversion".

BTW, the claim that kohl was prepared by sublimation or distillation seems bogus, I can't find any reference. Stibnite boils at arouns 1100 C, but unless air is excluded it will probably burn. All refs say that kohl was (still is) powdered by grinding the natural mineral.
Jorge Stolfi 08:18, 15 Jun 2004 (UTC)

If you're getting the "kohl preparation by sublimation/distillation" from my statement above about "European powder->refinement->distallation", please let me clarify. I meant that "distillation" was seen as morphologically analogous to "refinement", not that stibnite/antimony was processed by sublimation or distillation. (That's the problem with summaries — they're so short, they can leave out important distinctions or imply things they shouldn't. Sorry 'bout that.) The mutation of meaning would have taken decades or centuries and would be similar to the modern mutation of the word "computer" from its 19th century connotation of "accountant" to its current exclusive connotation of a machine whose most noticeable 21st century use is communication. And thanks for the Latin Vulgate quotes! I'll check them out. -- Jeff Q 19:07, 15 Jun 2004 (UTC)

Jeff Q, I saw the story about "alkuhul" being extened to "distilled essence" in other sources too. Perhaps there is also some chemical confusion going on, besides the linguistic one. It seems that antimony was quite popular among alchemists, because it has a colorful chemistry with many volatile compounds. Alchemical books and modern alchemy sites have many recipes for such compounds. They all start with stibnite (alkuhul), mixed with other substances and either melted (e.g. to prepare metallic antimony) or distilled (e.g. to prepare the reddish antimony trioxide, or "butter of antimony", etc). However the "alkuhul" itself is never produced by distillation, since it oxidizes readily. So it would be quite strange for its name to be assigned to "distilled essence". It may be that whomever "deduced" the folk etymology was not an alchemist himself...

Another page said that the linguistic confusion alkuhul/alcohol led to one of the Bible verses above being translated as "women who alcoholize their eyes". I will try to find that quote (I can't recall whether the page was in English, spanish, or what.)
Jorge Stolfi 00:36, 16 Jun 2004 (UTC)

This may just be hearsay, but growing up among Iranians I've always heard that it was the Persians that discovered alcohol. Since Islam grew rapidly threw Persia during the centuries mentioned above (mainly 12th century) it seems likely. I wonder if anyone has heard of this or has found any supporting evidence. I'm not suggesting it is true, but growing up everyone I was around took this as a fact. - User:djKianoosh 1 Jan 2005

Etymology from the OED: [a. med.L. alcohol, ad. Arab. al-ko{hdotbl}'l ‘collyrium,’ the fine powder used to stain the eyelids, f. ka{hdotbl}ala, Heb. k{amac}khal to stain, paint: see Ezekiel xxiii. 40. It appeared in Eng., as in most of the mod. langs. in 16th c. Cf. Fr. alcohol, now alcool.]

Eclectic origin history from EB:

• Before 6000 BC, beer was made from barley in Sumeria and Babylonia.
• Vitis vinifera was being cultivated in the Middle East by 4000 BC, and probably earlier. Egyptian records dating from 2500 BC refer to the use of grapes for wine making, and numerous Old Testament references to wine indicate the early origin and significance of the industry in the Middle East.
• Because the two ingredients necessary to alcoholic fermentation are widely spread and always appear together, civilizations in almost every part of the world developed some form of alcoholic beverage very early in their history.

Note also that it depends on what you mean by discovery. The beer was made then but that does not necessarily mean that they knew what was going on or what was in the beer that made them inebriated. Also, as the last one indicates, alcohol is a pretty common thing to come about so it's hard to say who first used it, and it might be that it was known to be Sumeria and Babylonia simply because they kept better records than the early peoples who didn't have writing, in Africa, for - Centrx 20:50, 3 Jan 2005 (UTC)

Link suggestions

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New chemistry section

I think the idea of a reactions section is great, thanks Andrew for all your hard work. I don't really have time to do all of the wikifying, though I did a few edits, but I was going to suggest the following: 1. My impression is that this page gets a lot of hits, much more than most chemistry pages. Most readers will not be looking for details of the iodoform reaction (which strictly is more of a reaction of methyl ketones than alcohols)! There are probably loads of things that could go on the page- and as an organic chemist I know where my sympathies lie, but we need to consider all readers. Therefore the page needs to cover material concisely, which means that much of the reactions section needs to be edited to make it take up less space. The only other way would be to create a new page called Chemistry of alcohols or something similar.

2. Personally I prefer organic reactions drawn on a program like IsisDraw (you can see my contributions in Image:Alcohol_reaction_examples.gif and Image:Alcohol examples.gif. (Though I didn't show carbons & Hs explicitly in the naming image, that would be better for beginners- one day I will correct that.) What do others think?

3. The chemical properties section of the phys/chem props section and the chemistry (prepn & rxns) sections need to be mostly combined. When I added some content to the former, I did it mainly to correct an error, and I always felt that a separate section on chemistry would be much better- now someone has done it (thanks!). But it is ludicrous for us now to have two separate sections giving two separate examples of preparation of alkyl halides. These need to be combined and unnecessary repetition removed. If I wasn't planning a holiday from Wikipedia I'd do it myself!

Walkerma 23:18, 2 Apr 2005 (UTC)

Major rewrite

I have just uploaded a major rewrite of this page covering all parts except the Etymology part (which I know little about, and which seems pretty good) and the Chemistry of alcohols part (which I will work on). It seems to me that this page is probably a page receiving many hits, so it needs to be clear and concise. Unfortunately it seemed to show the worst signs of having been "written by a committee", such that although much of the content was true and at relevant, it led to the page being very long and containing many obsure facts. It also meant that there was no overall balance, having (it seemed) never had one single person edit the whole thing.

I hope that this edit makes the page a lot clearer and "punchier". Here is a summary of what I did:

• I rewrote much of the first few sections, taking out errors, and adding a couple of pictures to clarify the text. I decided that the general formula didn't warrant its own section, so I made this one sentence, especially as the formula doesn't apply to many alcohols such as cyclohexanol, benzyl alcohol or ethylene glycol. It was organised such that the picture near the top could serve two sections, the methanol & ethanol section as well as the primary secondary & tertiary section.
• I have spun off the fatty alcohols on to their own page. These are not important enough to warrant a whole screen full of information one has to scroll though on such a busy page- as evidenced by the fact that it seems that none of the compounds listed has its own page. I moved the key info up into the "Other common alcohols" section with a link to the new page.
• I re-did the image in the properties section, so that there are other structures besides the line-angle formula. This should make the structures more readable for beginners.
• I also took out a big chunk of specific chemistry from the properties section and put it in the chemistry section further down. I felt what was need instead was a general overview of what alcohols are like chemically, so I wrote one, and added an image to explain things. I think general aspects like acidity and nucleophilicity are dealt with best in a section like this, while specific examples of these are best covered in the chemistry section.
• I plan to do a major rewrite of the chemistry section in the next few days, but thought I should put up what I had so far. Please add any comments you have right after this message. Walkerma 17:27, 15 Apr 2005 (UTC)

I have finished off the rewrite. It turns out to be only slightly shorter in terms of number of screenfulls, and slightly larger in terms of kB, but I think it flows rather better and is much more evenly balanced. I have taken out a lot of duplication. Much of the growth comes from putting in important information that was missing before- such as on dehydration to alkenes, acylation by RCOCl/py. I also added short verbal explanations where before there was just a list of equations. Walkerma 19:15, 18 Apr 2005 (UTC)