Talk:Formaldehyde/Archive 1

Archive 1

Paragraph on effect on BSA

The paragraph which mentions studies that have reported an effect on bovine serum albumin is poorly written, does not make sense and does not have a citation. I guess that it means that studies have shown that Formaldehyde affects bovine serum albumin and therefore, probably affects human serum albumin. As it is written, it isn't clear what it is saying but, it seems to imply that human body's carrier protein (whatever that means exactly) is bovine serum albumin.

The text of this paragraph is (at the time I am writing this) as follows:

Studies on the interactions between formaldehyde and proteins at the molecular level have been reported on the effects of the body’s carrier protein, bovine serum albumin. The binding of formaldehyde loosens the skeletal structure of BSA and exposure of aromatic ring amino acids in the internal hydrophobic region. Symptoms may affect personal awareness, making one feel tired or fatigue.

Unfortunately there is no citation to the studies mentioned(there is already a citation needed tag). If someone more knowledgeable could try to make sense of this and re-phrase this paragraph, that would be good. Sipos0 (talk) 16:24, 22 January 2012 (UTC)

Using formaldehyde as a desired Intoxicant

Formaldehyde is a type of embalming fluid. "Embalming fluid" is a slang term for a street drug, usually PCP, which people combine with something smokable, usually marijuana. I want to preface my question by saying that I have familiarity with these facts.

However, I also believe that a significant number of people take the slang term "embalming fluid" to mean formaldehyde, and they make efforts to smoke formaldehyde-laced marijuana and tobacco.

I work in chemical dependency treatment and people definitely say that they literally dip their marijuana or tobacco cigarettes into formaldehyde -even without PCP- and they smoke this after it dries. They describe the process as having a definite psychological effect and they profess having a long-term habit of doing this.

I see no reason in easily-accessible internet literature why formaldehyde should be a psychoactive substance and yet I am in contact with people who say that they regularly smoke formaldehyde. Can anyone direct me to citable source material that I could use to make a section on this page describing that, in fact, a significant number of people literally smoke formaldehyde and claim that its effects entice them to make a habit of the practice? Bluerasberry (talk) 22:25, 10 September 2008 (UTC)

Formaldehyde is used as a solvent in so-called "Fry". Maybe someone could add a paragraph about this topic.

CaffeineWitcher (talk) 14:51, 22 May 2020 (UTC)

Formaldehyde cannot used as a solvent, it's highly reactive. LeticiaLL (talk) 04:30, 30 June 2020 (UTC)

References

Methanal vs Methanol and preferred name

The 'formalin' page is redirected to this page. Actually 'formalin' is not the same as formaldehyde. Formalin is a saturated solution of formaldehyde, water, and typically another agent, most commonly methanol. A new page should be created for formalin and the use of the word 'formalin' in this article as a substitute for formaldehyde needs to be eliminated. Cheetah58 (talk) 14:29, 14 April 2008 (UTC)

It's Methanal: someone wrongly "corrected" this to "methanol". I've changed it back. Note that methanal is the same as formaldehyde, but that methanal is not the same as methanol.

• Also, before any IUPAC pedants step in, the preferred name is formaldehyde, as in the article, although methanal is also correct. Physchim62 20:53, 29 May 2005 (UTC)

• Isn't the IUPAC name 'methanal' though? So under 'IUPAC Name' it should say 'methanal' not 'formaldehyde'

Formula Writing

HCHO seems like an odd way to write the formula. Its structure is more like:

H    (H2CO)
 \
  C==O
 /
H

-Unknown

Regarding your comment that "HCHO seems like an odd way to write the formula", actually it is not because this way of writing the formula highlights it's functional group as an aldehyde R-CHO where R in this case is only hydrogen (H) making formaldehyde the simplest form of this functional group. -Unknown

I would have thought that as a carbonyl group (C=O) is involved it should be written HCOH or maybe H₂CO. —Preceding unsigned comment added by 58.96.114.192 (talk) 08:02, 18 June 2010 (UTC)

HCOH would give the impression that the molecule contains a hydroxide group, which it does not. While HCHO looks a bit weird, it's consistent with how you'd write other similar molecules, emphasizing that it is an aldehyde. - Alltat (talk) 12:15, 24 December 2011 (UTC)

Picture

Can someone find or make a better picture? Current one does not show the 'C' and while it may be obvious to a chemist might mislead or confuse some people. -Unknown

I can draw that out using my Chemsketch and convert the file into JPEG format, but how do i attach the file onto this page? -Unknown

Reaction products: paraformaldehyde + nitric acid

Can anyone help to determine the rection products of a reaction using paraformaldehyde (solid) and concentrated nitric acid? Thanks. -Unknown

If you insist that it is paraformaldehyde that reacts, then there is no way of completing the above reaction for you because paraformaldehyde itself is a polymer (oligomer). Usually acid is added to paraform when mixing it with formalin or water in an attempt to make a solution of formalin. -Unknown

As the de-/polymerization of formaldehyde is effectively catalyzed by acids, I would expect cleavage of paraformaldehyde to monomeric formaldehyde wich would then be oxidized to formic acid. The reaction may proceed vigorously. (just a guess)

Products that utilize formalin

Shampoos, eg. Glycolemon Henna shampoo contains formalin. Why is this not included under uses, what is the purpose of the formalin, and how toxic would this be? 41.243.143.160 (talk) 12:53, 27 January 2012 (UTC)David Gwynne-Evans

Formaldehyde in beer

Is Formaldehyde used in beer? Heard that some Japanese beer contained Formaldehyde.....true? (posted to article by 220.108.208.252, moved here 04:27, 2 Jan 2005 (UTC))

Watched a movie called 'Good morning Vietnam' (Robin Williams) last night. Was shocked that the Vietnamese beer contained formaldehyde. But not too sure if that's true. -Unknown

I would not be suprised to find that beer contained small amounts of formaldehyde. Fermentation has a lot of minor byproducts. Shimmin 14:32, Feb 16, 2005 (UTC)

Couldn't find anything about formaldehyde in Beer Lao after googling around. should we remove that sentence? —Preceding unsigned comment added by 121.6.200.62 (talk) 12:28, 15 July 2007

Yeah, there's formaldehyde in most fermented beverages; but the levels are lower than safe drinking water limits. Basically, you'd die of alcohol poisoning long before you could ingest enough formaldehyde to be dangerous. --Astockto (talk)astockto —Preceding undated comment added 19:50, 19 February 2010 (UTC).

Formaldehyde kills most bacteria?

I'm not quite sure about this I thought it killed everything spores inculded. We use it to sterilze the HEPT filters. http://encarta.msn.com/encyclopedia_761578019/Formaldehyde.html

Boiling Point Temperature?

Entry says that the boiling point is -21 celsius, or 262 Kelvin; this is wrong. Minus 21 celsius is 252 Kelvin, 262 Kelvin is -11 Celsius. Which of these is correct? DS 16:24, 14 August 2005 (UTC)

Uppercase degrees "Celsius", lowercase "kelvins". -Unknown

Don't ovrlook the fact that the infobox value is different from either of those numbers: -19.0 °C (254.1 K) (and I wouldn't bet on there being a significant zero in that number). Gene Nygaard 18:25, 14 August 2005 (UTC)

253.85±0.2 K according to NIST, which converts to -19.3±0.2 °C. I shall change the infobox and text accordingly. Physchim62 18:34, 14 August 2005 (UTC)

Organic molecules in space

According to Isaac Asimov's Guide to Science, formaldehyde is also found in interstellar space. -Unknown

Is it a Carcinogen?

While this might be true, I'd like to see a source on it. You can't just label something a carcinogen after all, I think we need an explanation of how it causes cancer. As far as I know, that involves damaging DNA, since damaged DNA is what leads to cancer. I'm not sure how formaldehyde would do that. Tyciol 05:30, 19 February 2006 (UTC)

Carcinogenicity is usually measured by exposure studies on experimental animals and (where applicable) on humans, rather than by a purely mechanistic approach. At Wikipedia, we usually rely on the monographs published by the IARC, which are internationally recognised: the IARC classes formaldehyde as a group 1 carcinogen, the highest level. Details of the studies can be found in the links I have added at the bottom of the article. Physchim62 (talk) 07:16, 19 February 2006 (UTC)

Thanks, now I know where to look on information. I think case studies and evidence like you've said, are very important. Even so, I think it's more sufficient to at least have an operating theory on how the carcinogen functions in increasing cancer risk, because then countermeasures can be invented. The reason I'm drawn to this article is my investigation into Aspartame, and the metabolism-produced formaldehyde and how they might differ in health risks. Tyciol 16:59, 20 February 2006 (UTC)

To hazard a guess, formaldehyde would react with the free amino groups on DNA bases producing Schiff bases, which could effectively be reduced to methylated bases. It also apparently promotes DNA-protein cross linking, possibly by a similar mechanism. Both of these would interfere with DNA transcription and hence be carcinogenic. As for metabolic formaldehyde, you would need to look at where it is produced; I would image that aspartame is mostly metabolized in the liver, so the formaldehyde would be rapidly oxidized out of harm's way. The three cancers which are associated with formaldehyde exposure are nasopharyngeal cancer, leukemia and sinonasal cancer, characteristic of cell damage at or near the site of exposure (by inhalation). Physchim62 (talk) 18:45, 20 February 2006 (UTC)

Cool thanks. I'm going to study these terms so I can get more familiar with methylation and stuff. That info about aspartame being oxidized is good though, now I can get some diet pop... because sugar's a cancer contributer too in excess, also crosslinking proteins and stuff. Tyciol 03:53, 21 February 2006 (UTC)

The statement citing "studies" that show no evidence of carcinogenicity at low levels still needs a citation. Cognisant that carcinogenesis is a stochastic process, I'm not sure if the statement is defendable. I added a reference to the IARC determination of sufficient evidence, and corrected the dose threshold for non-stochastic effects (irritation) citing Health Canada and USEPA.Vdaliessio 18:40, 5 March 2007 (UTC)

I am new at this so I hope I am doing this correctly. May I offer two items for consideration? First, the url for the June 2004 IARC news release is http://www.iarc.fr/ENG/Press_Releases/archives/pr153a.html. The release is entitled "IARC CLASSIFIES FORMALDEHYDE AS CARCINOGENIC TO HUMANS." The US National Toxicology Program (part of HHS) is the keeper of the official US carcinogens list. Based on a nomination from NIEHS, NTP will consider codifying for the US the IARC 2004 determination, i.e., to move formaldehyde to known human carcinogen status. The NTP url is http://ntp.niehs.nih.gov/index.cfm?objectid=7BE524E1-F1F6-975E-76BB0ABD6CC9076A. Second, the article states that it needs a footnote for the statement that formaldehyde is a common indoor air pollutant. As one authority, I would offer the 2005 California EPA Air Resources Board Report entitled "Indoor Air Pollution in California." The url for the Report is http://www.arb.ca.gov/research/indoor/ab1173/finalreport.htm and the section on formaldehyde begins on page Report page 65. A point of full disclosure - I am with Johns Manville, which in 2002 switched its entire line of fiber glass building insulation to no added formaldehyde. We thought it was a smart thing to do and it has been well recieved. So, formaldehyde health issues are important to us. Thanks. bruceray-jm; 9-11-07 —Preceding unsigned comment added by Bruceray-jm (talk • contribs) 03:02, 12 September 2007 (UTC)

I think it's time to split the Safety section into at least 2 parts - occupational exposure and residential exposure. I will try to comb this out later when I have time, but suggestions are welcome. Some editors have added data from occupational studies conflating occupationa and residential exposures, and that have the effect of downplaying the significance of residential exposures at lower levels.Vdaliessio (talk) 16:26, 16 December 2010 (UTC)

Oxide Catalyst

It is unclear which iron oxide is used (does it matter?) and whether the molybdenum and vanadium are present as the metal or as oxides. Does anyone know more?

Allergen?

I strongly doubt that there is a formaldehyde allergy, as an allergy is an IgE-dependent response which can hardly be caused by a small molecule. There might well be a formaldehyde hypersensitivity. And we obviously need better sources for that (i.e. from the scientific literature). Icek 12:38, 6 July 2007 (UTC)

European Ban

I added that Europe was banning formaldehyde on the 22nd of Semptember, 2007. The section 'Embalming' now needs cleaning up (it no longer makes sense the way it is phrased). Can somebody help with this? Dancanm 18:39, 9 July 2007 (UTC)

I have tried to do this by moving a passage around. I have deleted the following passage :

'The European Union is considering a complete ban on formaldehyde usage (including embalming), subject to a review of List 4B of the Technical Annex to the Report from the Commission to the European Parliament and the Council on the Evaluation of the Active Substances of Plant Protection Products by the European Commission Services'

I hope it makes a bit more sense now. Also see my comment in the 'Embalming' section below.--Godfinger 19:33, 22 August 2007 (UTC)

I edited and added this section, several sources can be googled to verify this information:

The official sources (http://ecb.jrc.ec.europa.eu/esis/), who are the ones I'd trust most, do not verify this information at all! Please, please, verify the information you find in random web articles before you edit. I'm leaving the original here so others will know what I'm referring to. Astockto (talk) 19:02, 19 February 2010 (UTC) astockto 19 Feb 2009

I agree with this section being a bit hard to read - I can't tell if it has been banned in Europe for embalming purposes. I can't find that Wall Street Journal reference either for follow up. I'm keen to help clean this page up a bit but I'm new to Wiki editing. Nobornadiene (talk) 05:24, 6 October 2020 (UTC)

European Ban

After nearly 10 years of planning, the European Union set the ban of formaldehyde/formalin within Europe for September 22, 2007, due to its carcinogenic properties. The ban on sales and marketing came on the heel of a ban on phenol in 2006. The formaldehyde/formalin ban was on top of the REACH ban on its manufacture and the ban brought in by the French Government under its CMR program. The Registration, Evaluation and Authorization of Chemicals (REACH) law ultimately covered 30,000 chemicals, with the most dangerous and toxic acted upon first. All chemicals must be registered by manufacturers over a certain tonnage use and a dossier submitted to verify properties, usages, and handling protocols with carcinogens, mutagens, toxics, and environmental bioaccumulaters or biopersistents requiring special authorizations and plan submissions for elimination with safer chemical replacements. Formaldehyde qualifies under essentially all the ramifications of the law being over tonnage, a documented carcinogen/mutagen and generally considered a toxic chemical in end use.European Union Bans formaldehyde/formalin within Europe | publisher = European Commission's Environment Directorate-General | date = September 2007 | url = http://ec.europa.eu/environment/biocides/pdf/070622_withdrawal_notice.pdf | pages = 1-3}}.

Formaldehyde in marijuana?

Far be it from me to question whoever wrote this section, but I hardly think formaldehyde is frequently found in marijuana.

Marijuana, like most leafy plant materials is rich in sugars and starches, when these are combusted at less than stoichiometrically optimum air / fuel ratios, the partial combustion products likely contain aldehydes including formaldehyde. I assume this is what the section refers to. Same is true for tobacco cigarettes and others.Vdaliessio (talk) 18:57, 7 March 2008 (UTC)

I'm pretty sure this is referring to a substance being added to marijuana. That Substance being Phencyclidine or PCP. The drug is often called "Embalming Fluid". (talk) 14:51, 25 March 2008 (UTC)

Embalming

I added a reference that I think supports the following statement that was previously uncited :

Countries with a strong tradition of embalming corpses, such as Ireland and other colder weather countries, have raised concerns.[7]

The link leads to a Wall Street Journal article but the full article is only available to subscribers of which I am not, so I was not able to check if it actually supports the statement but it looks like it probably does from the first paragraph. It would be a good idea to check it to see if the reference is accurate-so if anyone is a subscriber could they check it and see if it is suitable.--Godfinger 19:06, 22 August 2007 (UTC)

It is true that Formaldehyde can be added to Marijuana but it is not found in it. I don't believe Formaldehyde would be productive in the growth process of this rather sensitive plant. Usually, someone will soak a rolling paper in a "formaldehyde" solution more commonly refered to as embalming fluid. This can cause halucinagenic effects similar to LSD. —Preceding unsigned comment added by 12.43.88.120 (talk) 17:27, 16 March 2009 (UTC)

Synthesis from ethanol

I have been unable to find the mentioned small scale synthesis of formalin from ethanol. I will ask for a citation, and remove the statement if no-one can find one. 95.34.36.85 (talk) 19:56, 26 January 2009 (UTC)

Removal of content on astrochemistry of CH2O

I removed the majority of a large essay on interstellar CH₂O, retaining only the discovery and a recent reference. The section seemed unusually specialized and of probable narrow interest, possibly suited for a more specialized article but occupying space disproportionate for this article, IMHO. If other editors have misgivings, feel free to reinstate, I was just doing what I think is best for the encyclopedia.--Smokefoot (talk) 14:22, 13 February 2009 (UTC)

• the Interstellar formaldehyde page already existed so I moved everything there V8rik (talk) 17:25, 13 February 2009 (UTC)

Enviromental impact?

Does Formaldehyde decompose gracefully in nature or does it stay around and poison the water resources? Electron9 (talk) 10:07, 20 November 2009 (UTC)

Formaldehyde undergoes photodecomposition in sunlight. Other removal paths exist involving microorganism. National Research Council (U.S), Committee on Aldehydes, Board on Toxicology and Environmental Hazards, Assembly of Life Sciences, Formaldehyde and Other Aldehydes, National Academy Press, Washington, D.C. 1981.Briselame (talk) 17:54, 4 December 2009 (UTC)

Dental composites?

There are a number of blogs and sites now that allege that this substance is given off in small amounts over time by "white fillings." Does anyone know for sure or have a reliable source that tells us about it? Rumiton (talk) 14:48, 21 February 2010 (UTC)

It is interesting to hear about formaldehyde being in the dental news. For Wikipedia, I would recommend against including that kind of information. WP is not into current events nor is Wikipedia a suitable mechanism for public health alerts, although many try to use it that way. And the sources sought are well digested, see WP:SECONDARY. --Smokefoot (talk) 18:10, 21 February 2010 (UTC)

I don't have access to dental sources and certainly don't intend to use Wikipedia for any purposes other than those for which it is intended. Do you know of any "well digested" sources that raise this particular issue? Is it entirely a minority opinion? (Personally, I hope so. I have a mouth full of them and don't want to change.) Rumiton (talk) 11:54, 22 February 2010 (UTC) Here is an apparently academic reference to a patient experiencing anaphylactic shock after exposure to a "filling containing formaldehyde." I am starting to feel disturbed. Will look further. Rumiton (talk) 12:24, 22 February 2010 (UTC)

Splitting the article

I propose to split off the bio-medical-safety aspects of this article. We split off sections of articles that have large biomedical or toxicity sections - such as cyanide poisoning from cyanide. Suggestions for the title of the new article? "Health Effects of Formaldehyde"? --Smokefoot (talk) 00:53, 1 December 2010 (UTC)

I think if we can summarize all the "OMG, TOXIC POISON!!!" sections, the existing single article will do just fine. --Rifleman 82 (talk) 04:44, 1 December 2010 (UTC)

I agree that the hazards for most chemical articles are routine and merit no separate article much less a paragraph, but if you watch this one, there is a lot of concern because formaldehyde is used in building materials and is emitted into the atmosphere in a way that affects the occupants. So my guess is that even correcting for the chemically illiterate who are simply pasting in hysteria and bloggy-cruft, a core of serious public interest in the topic of EH&S. So let's watch. --Smokefoot (talk) 18:58, 1 December 2010 (UTC)

Obsolete or not?

According to IUPAC recommendations (see IUPAC Green Book http://old.iupac.org/publications/books/gbook/green_book_2ed.pdf and also page 1387-1388 of http://www.iupac.org/publications/pac/67/8/1377/pdf), the units ppm, ppb and ppt should not be used. That's why I have replaced them. Please let's discuss this here and not start an edit war! RolfSander (talk) 22:33, 4 March 2011 (UTC)

It may the unprefered units by IUPAC's account, but it is still prefered by the general public which is what Wikipedia is aimed at. Plasmic Physics (talk) 01:54, 5 March 2011 (UTC)

True, and if this was the only problem, I would agree to stick to the more commonly used units ppm, ppb, and ppt. However, there is also the problem of ambiguity. The wikipedia manual of style says: "Only in the rarest of instances should ambiguous units be used". I can see at least 3 ambiguities with the old units:

• "ppb" may either refer to mass fraction or mole fraction, which are quite different.
• The "b" in "ppb" stands for billion, which can either be 1E9 or 1E12, see Long and short scales.
• "ppt" is even worse: it may either refer to parts per trillion (1E-12) or to parts per thousand (1E-3). — Preceding unsigned comment added by RolfSander (talk • contribs) 02:56, 5 March 2011 (UTC)

If you think it's worth considering, submit your suggestion at WT:Chem. Such a change would affect a large number of articles, I'm sure they'd be interested in argueing for or against your case. Plasmic Physics (talk) 03:31, 5 March 2011 (UTC)

These standards were written in ppm/ppb, and they should stay that way. They are usually understood to be mass/mass quantities, not molar fractions. The Green Book can say whatever it wants but until people stop using these quantities for real, we should not introduce new ambiguity by (possibly mis-)converting them. --Rifleman 82 (talk) 15:42, 5 March 2011 (UTC)

@Rifleman 82: No, in atmospheric chemistry people usually refer to molar fractions, not mass fractions! This is exactly the ambiguity/confusion that comes with the ppm/ppb/ppt units. Fortunately, for HCHO the difference is small because HCHO and air have similar molar masses. For other species, the difference can be large. @Plasmic Physics: Thanks for the suggestion, I will discuss this at WT:Chem. RolfSander (talk) 16:37, 5 March 2011 (UTC)

Density

Hi. How can the densitiy of a gas be more than 1? Also the temperature is not given. Please check it. --Azaline Gomberg (talk) 11:04, 17 May 2011 (UTC)

I changed the data to reflect the liquid density at -20 °C, just below the boiling point. -- Ed (Edgar181) 13:24, 17 May 2011 (UTC)

Melting point

-92C specified as melting point value, source traced to something noted as BG Chemie (1991) (some German chemical journal?) Other sources exist with melting point specified as -118C (e.g. vpl.astro, Canada Health Federal department). Can somebody investigate what is the right value (or may be range)? Shufel (talk) 08:59, 22 August 2011 (UTC)

Formaldehyde releasers as preservatives in consumer products

Many consumer products contain diazolidinyl urea and related chemicals. These work by releasing formaldehyde. Particularly troubling is the use of these compounds in cosmetics, shampoos, conditioners skin care products, lotions creams, moisturizers, makeup, sunscreen, soaps, baby wipes, cleaning agents and other products where they come into contact with the skin. Diazolidinyl urea and related chemicals are emerging as an major cause of dermatitis via hyper-sensitization due to long-term exposure. This article should contain a paragraph about this in the safety section. Senor Cuete (talk) 16:31, 2 June 2012 (UTC)Senor Cuete

LD50

I see quite a range in the oral toxicity values being used for formaldehyde, with an LD50 as low as 42 mg/kg (mice) or as high as 500mg/kg (rats). That seems off to me, though I'm no expert. I can't find a citation for the 100 mg/kg used in this infobox, and it looks like the MSDS has been moved. Any clue where it came from? ADStark (talk) 00:17, 13 September 2012 (UTC)

Safety section needs up-to-date info

For example, the article announces that in November 2008, additional testing will begin regarding the Iowa floods of 2008 incident. — Preceding unsigned comment added by Osmoregulator (talk • contribs) 15:19, 4 December 2012 (UTC)

Formaldehyde is a highly toxic substance and this article seems to be influenced a lot by people who are trying to portray it as harmless. For example, the safety section claims that ingestion of a few ml's is harmless, which is preposterous to anyone who has worked in a lab, but the reference for this claim actually says this: "Ingestion of as little as 30 mL (1 oz.) of a solution containing 37% formaldehyde has been reported to cause death in an adult." — Preceding unsigned comment added by 100.19.43.144 (talk) 22:46, 10 October 2020 (UTC)

Reactions

Just going to list some reactions:
CH4 + H2O --> H3COH + H2 / H2CO + 2 H2 / CO + 3 H2
H3COH -Pt-> H2CO + H2, CO + H2 --> H2CO
H2CO + H2O --> Formic acid + H2
H2CO + NH3 --> HCONH2 + H2
H2CO + CH4 --> HCOCH3 + H2
H2CO + CH4 + H2O --> H3CCOOH + 2 H2
H2CO + CH4 + NH3 --> H3CCONH2 + 2 H2
H2CO + 2 CH4 --> H3CCOCH3 + 2 H2
2 H2CO --> HCOCOH + H2 / 1,3-Dioxetane / H3COCOH / CO2 + CH4
3 H2CO --> Trioxane / HCOCOCOH + 2 H2 / H3COCH2OCOH
4 H2CO --> (CO)4 + 4 H2 / (CH2O)4 / H3COCH2OCH2OCOH / Bis(methylenedioxy)methane + CH4
5 H2CO --> (CO)5 + 5 H2 / (CH2O)5
6 H2CO --> (CO)6 + 6 H2 / (CH2O)6
As well as a variety of other shapes. There are at least several different kinds of paraformaldehyde. There is one that is an infinite polymer of carbonyl groups (-C=O-)n that releases hydrogen when forming, and the closures of small oligomers of that make (-C=O-)n rings. Then there are are ester polymers of formaldehyde, like 1,3-Dioxetane and 1,3,5-Trioxane. Other than the even numbered rings, there is an infinite polyester, (-CH2-O-)n, and a polymer of any length ending with a formyl group. Rings linking up can make paraformaldehyde more like a polyester glass, with rings linking together. The paraformaldehyde with infinite carbonyl groups has much different properties than the infinite polyester form.
Hydrolysis of paraformaldehyde can be demonstrated with these reactions:
HCOCOH+ H2O --> H2CO + HCOOH (Glyoxal is the first member of the (-C=O-)n paraformaldehyde)
H3COCOH + H2O --> H3COH + HCOOH (Methyl formate is the first member of the (-CH2-O-)n paraformaldehyde)
The cyclic varieties are more resistant to hydrolysis.
Hydration of formaldehyde:
H2CO + H2O --> HOCH2OH
2 HOCH2OH --> HOCH2CH2OH + H2O2
2 HOCH2OH --> HOCH2OCH2OH + H2O
In other words, hydration of formaldehyde makes the (-CH2-O-)n paraformaldehyde favored over the (-C=O-)n version. It also makes some ethylene glycol, which makes (-CH2-CH2-O-)n sections of the polyester that are more flexible.
H2CO + NH3 --> H2NCH2OH
H2CO + 2 NH3 --> H2NCONH2 + 2 H2
H2CO + O2 --> CO2 + H2O
H2CO + HF --> HCOF + H2
HCOF + HF --> F2CO + H2
H2CO + F2 --> F2CO + H2
H2CO + PH3 --> HPO + CH4
H2CO + P(OH)3 --> OPOH + HOCH2OH
OPOH + 2 HOCH2OH --> H3PO4 + 1,3-dioxetane + H2
Generation of ethene catalyzed by TPPO:
H2CO + Triphenylphosphine oxide --> O2 + H2C=PPh3
H2C=PPh3 + H2CO --> OPPh3 + C2H4
Reactions with H2S:
H2CO + H2S --> H2CS + H2O
H2CO + H2S --> HCOSH + H2
H2CO + H2S --> HCSOH + H2
Polymerizations with H2S: n H2CO + n H2S --> (-S-)n + n H3COH
6 H2CO + 6 H2S --> S6 + 6 H3COH
8 H2CO + 8 H2S --> S8 + 8 H3COH
n H2CO + n H2S --> (-S=O-)n + n CH4
n H2CO + n H2S --> (-CH2-S-)n + n H2O
3 H2CO + 3 H2S --> (CH2S)3 + 3 H2O
n H2CO + n H2S --> (-CH2-S=O-)n + n H2
n H2CO + n H2S --> (-C=O-S-)n + 2n H2
n H2CO + n H2S --> (-C=S-)n + n H2O + n H2
n H2CO + n H2S --> (-C=S-O-)n + 2n H2
2n H2CO + n H2S --> (-CH2-CH2-O=S=O-)n
2n H2CO + n H2S --> (-C=O-S=O-)n + n CH4 + n H2
2n H2CO + n H2S --> (-C=O-C=O-S-)n + 3n H2
2n H2CO + n H2S --> (-C=O-CH2-S=O-)n + 2 H2
2n H2CO + n H2S --> (-CH2-C=O-S=O-)n + 2 H2
And many more, probably. --User:Zuloo37 — Preceding undated comment added 03:16, 17 October 2014 (UTC)

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Acidity (pKa)

The article has given a pKa of 13.3, without any reference. If you deprotonate foraldehyde, you get formyl anion, which never has been observed. So there is no known pKa for formaldehyde. Please remove it. 85.19.205.254 (talk) 08:29, 27 November 2015 (UTC)

It is the pKa of hydrated formaldehyde (HO-CH2-OH), which is the major species in aqueous solution.138.246.2.61 (talk) 18:53, 5 October 2016 (UTC)

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Assessment comment

The comment(s) below were originally left at Talk:Formaldehyde/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.

There should be a section on Paraformaldehyde. there are over 3000 citation in pubmed. It is a essential tool in histological analysis of tissues with over 3000 citation in pubmed. 4: Augusteyn RC, Vrensen G, Willekens B. The effect of paraformaldehyde fixation and PBS storage on the water content of the human lens. Mol Vis. 2008 Jan 17;14:90-4. 14: Lyck L, Dalmau I, Chemnitz J, Finsen B, Schrøder HD. Immunohistochemical Markers for Quantitative Studies of Neurons and Glia in Human Neocortex. J Histochem Cytochem. 2007 Nov 12;

Last edited at 04:36, 14 February 2008 (UTC). Substituted at 15:23, 29 April 2016 (UTC)

Removed "Treatment" section

I just removed the "Treatment" section (added here: https://en.wikipedia.org/w/index.php?title=Formaldehyde&type=revision&diff=714042828&oldid=712477806). It was looking like an advertisement, was not encyclopedic, had no references whatsoever, was partially unrelated and badly written. --Antifumo (talk) 23:46, 10 June 2016 (UTC)

I removed it again for the same reasons. ChemNerd (talk) 13:43, 20 June 2016 (UTC)

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Borax

Reads: "Besides using formaldehyde, they also used borax, but not in combination." Relevance? Nicmart (talk) 15:27, 23 February 2017 (UTC)

I removed that sentence.--Quisqualis (talk) 19:34, 24 October 2018 (UTC)

As an air pollutant

"They found that the instruments used to analyze haze particles can easily misinterpret sulfur compounds as sulfate when they are, in fact, a molecule called hydroxymethane sulfonate (HMS). HMS is formed by the reaction of SO2 with formaldehyde in clouds or fog droplets." https://www.seas.harvard.edu/news/2018/10/clearer-path-to-clean-air-in-china https://www.atmos-chem-phys-discuss.net/acp-2018-1015/acp-2018-1015.pdf User:Fred Bauder Talk 16:26, 23 October 2018 (UTC)