Talk:Hydrogenation

message: Why is there no mention of Hydrogenes, the ancient greek scientist who first discovered the phenomenon? --Dante Alighieri 09:37 18 Jul 2003 (UTC)
:Because noone has written it yet?  Why don't you :) Mat-C 12:52, 29 Apr 2004 (UTC)
thread_title: [[Hydrogenes]]

message: What is the difference between hydrogenation and protonation?  Is it simply that hydrogenation is the addition of H2 while protonation is the additon of H+?  This should be addressed in the article. --Ttownfeen 00:43, 28 February 2007 (UTC)
thread_title:  Hydrogenation vs. Protonation 

message: I understand that the process for making butter from cream is very different than that for hydrogenating vegetable oils into margarine, but is there any chemical similarity in the result? Can one say that butter is "naturally hydrogenated" to some extent, or is it instead the case that butter's solidity at room temperature is different than margarine's?
(Trying to partially deflate an email that makes out margarine to be the devil. I say it's only a minor demon.) 69.248.200.36 17:26, 19 August 2007 (UTC)
replies: text: Hydrogenation is the chemical process of adding H atoms to stuff, converting unsaturated molecules into molecules that are more saturated. Making butter from cream is a physical process that congeals the fat globules (the whiteness of milk or cream) without changing the degree of saturation of these fats. Butterfat in these globules is 65% saturated.  Margerine has a lower percentage of saturated fat than does butter.--Smokefoot 00:17, 21 August 2007 (UTC)
thread_title:  Butter 

message: Anyone know (or better also have a picture) of the apparatus used to measure the amount of H2 taken up in the reaction? I recall using an apparatus which appeared to be a burette with a pipe connected to a separating funnel full of a coloured liquid and sort of lining up the levels of a liquids in the funnel and the burette and measuring the volume removed (something to do with pressure equalization  ... bit of a sketchy description I know! -- Quantockgoblin (talk) 16:55, 28 April 2008 (UTC)
thread_title:  measuring gas used 

message: What is the purpose of hydrogenating protein?  I bought some peanuts that have "hydrogenated soy protein" listed as an ingredient.   What is the purpose of this?--Hraefen Talk 18:50, 23 June 2008 (UTC)
replies: text: There are so few results after searching for "hydrogenated soy protein" in Google Books, Google Scholar, and even Google, that I wonder if this is not a mistake. On the other hand, there are lots of results if you search for "hydrogenated soy oil", which makes sense. --Itub (talk) 08:05, 26 June 2008 (UTC)
thread_title: Hydrogenated protein?

message: Can solids ever by hydrogenated? Like, could you ever find whole nuts that have been hydrogenated? 
How can you tell if pig fat (unrendered lard) that you buy in whole chucks at the meat section in the supermarket is hydrogenated?  —Preceding unsigned comment added by Jacktherrr (talk • contribs) 13:58, 22 January 2009 (UTC)
replies: text: No, this only works in solution. Cacycle (talk) 14:57, 22 January 2009 (UTC)

text: No, it's not possible, because the alkene bond must adsorb on the catalyst surface for the reaction to occur. This is possible only for fluids. Hydrogenation without a catalyst does not occur at reasonable temperatures.  As for pig fat, there's no reason to hydrogenate it. Partial hydrogenation is/was used for converting cheaper plant oil (liquid unsaturates) into a more solid saturate/trans-unsaturate mixture to replace the more expensive saturated fats from animal sources, like butter or lard. When you already have expensive solid fat from an animal source, like lard, there's no point in hydrogenating it. --Vuo (talk) 00:07, 23 January 2009 (UTC)
replies: text:  Lard and butter is usually hydrogenated to extend shelf life and improve texture, hence they also can't be trusted not to contain artificial trans fat anymore. (Just search for hydrogenated lard) Ma770 (talk) 10:57, 6 May 2010 (UTC)
thread_title:  Is it possible to hydrogenate solids (like nuts, whole chuncks of pork fat, suet)? 

message: Electrolytic hydrogenation is commonly done in lab settings. It gets very high yields when converting ketones to 2ndary alcohols, aldehydes to primary alcohols, and alkenes to alkanes. It just uses an iron cathode which also acts as a catalyst and a sacrificial nickel anode. You can view the source here: http://pubs.acs.org/doi/pdf/10.1021/ed081p1350
I'm not sure if it warrants a spot in this article as it may be too specific of a process. Kasooi (talk) 02:05, 19 August 2011 (UTC)
thread_title:  Electrolytic Hydrogenation 

message: I just thought I would mention this tiny mistake, sorry for the pedantry:
A triacylglycerol containing two linoleate residues and one oleate residue is shown as being partially hydrogenated to a triacylglycerol containing two oleate residues and one stearate residue. However, the picture incorrectly shows a palmitate residue in place of the stearate. I don't know how to edit images, sorry.  — Preceding unsigned comment added by 205.250.1.132 (talk) 03:57, 21 June 2014 (UTC)
thread_title:  The image of the hydrogenation reaction 

message: I had commented that hydrogenated vegetable oil should point here, rather than to trans fat because I thought it was misleading.  On further thought, it should really point to saturated fat.  I would guess most people put these terms in from ingredient labels, and they would be best served by being taken to something relevant to their questions.  I believe on US labels, simply saying "hydrogenated" means hydrogenated to saturation.  — Preceding unsigned comment added by 71.127.245.95 (talk) 12:51, 2 October 2017 (UTC)
thread_title:  Redirections 

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thread_title:  External links modified 

message: -1) header of last column : there must be enthalpy of hydrogenation rather than "heat of hydrogenation", since negative values are given, and the fact that C-C double bond hydrogenation is exothermal (as otherwise mentioned in the text) and the well known relation QR(heat of reaction) = - delHR(enthalpy of reaction) ;
-2) values in the last column are much too small (or, in other words, much too high in absolute value) or the unit, kcal/mol, is wrong !  If the unit is changed to kJ/mol, the values ranges given in this last column  become acceptable.
In conclusion I've changed the unit from kcal/mole to kJ/mole and delete all the minus signs (or replace the 4th column header with Enthalpy of hydrogenation), in order to correct the table.
Refs:
1. F. A. Carey, Organic chemistry, McGraw-Hill, 2004, 5ed., p. 233, Table 6.1., where (correctly named) positive values given for "Heat of hydrogenation" are ranging between 136 kJ/mole (32.6 kcal/mole) for ethylene and 110 kJ/mole (26.4 kcal/mole) for 2,3-dimethyl-2-butene.
2. In Tables 10.36 (p.374),  10.37 (p.379) of ref. [4] (Barnicki in Kent Handbook, 12th ed.)  quoted for the header of 4th column, the correct unit, kJ/mole, is specified. Unfortunately, in the original reference [4] same misleading naming is used, i.e. "Heat of reaction" instead of Enthalpy of reaction, in Table 10.36 for the (negative) values given for hydrogenation of various functional groups and in Table 10.37 for (positive) values listed for dehydrogenation reactions.  
Regards, Liv.Ichimescu (talk) 17:36, 18 February 2018 (UTC)
replies: text: I agree there were lots of inconsistencies. The cited ref has negative values (and one was also not transcribed correctly) in units of "kJ/gmole", so your kJ/mol is clearly a correct correction. The cited ref notes that the reaction is "highly exothermic" and in previous and subsequent pages appears to use "ΔHrxn" for this idea. Our heat of reaction points to the ΔH sense also, and specifically identifies "Standard enthalpy of hydrogenation" as a known phrase. DMacks (talk) 21:11, 18 February 2018 (UTC)
replies: text: Might have been my fault, but in any case it is great that Ichimescu improved the table!  It would be good to have an entry for aromatics, showing the the enthalpy is not three times that of isolated alkenes.--Smokefoot (talk) 21:36, 18 February 2018 (UTC)
thread_title:  Corrections made in Table entitled "Substrates for and products of hydrogenation" in same topic (1.3.) 

message: The first paragraph mentions hydrocarbons, but it also can be used to hydrogenate hydrocarbon parts of larger molecules, such as (as we well know) fats. Is there a more general word that can be used? Gah4 (talk) 21:58, 22 July 2021 (UTC)
thread_title:  only hydrocarbons 

message: There is a question about syn addition. It seems that syn addition is important for cyclic molecules, where it can't rotate around the (single) bond after hydrogenation. As well as I know, that isn't usual in the case of hydrogenated fats, but then this article isn't specific to them. But I think the section mentioning syn addition should also mention that it applies for cyclic molecules. Gah4 (talk) 04:31, 8 February 2022 (UTC)
thread_title:  [[syn addition]] 

message: The redirect Partially hydrogenated oil has been listed at redirects for discussion to determine whether its use and function meets the redirect guidelines. Readers of this page are welcome to comment on this redirect at  until a consensus is reached.   Jay 💬 05:20, 6 August 2023 (UTC)
thread_title:  "[[:Partially hydrogenated oil]]" listed at [[Wikipedia:Redirects for discussion|Redirects for discussion]]