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Author: Subject: Increasing melting temperature in vegetable wax
davidpcrawford
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[*] posted on 9-7-2010 at 10:57
Increasing melting temperature in vegetable wax


Hello all,

I am not a chemistry student, but am in need of an answer. I like making candles at home, I live in a rural area, and have discovered palmwax. It is way better than paraffin in terms of fumes and chemical releases, I am highly allergic, but they drip way too much. I could use a container to put the wax in but for the farm it creates issues, so I need to make taper palm wax candles. What kind of chemical additive could I use, ideally even something that I can grow, to increase the melting temperature of the palm wax so that it hardens before if drips down the candle? There has to be something out there that either increases the melting temperature or increases the coagulation of the wax, thereby hardening it. Any thoughts?Any help of thoughts would be great....
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[*] posted on 9-7-2010 at 11:58


Have you talked to any hobbyist wax suppliers? They advertise both high melting point wax and various additives which increase the melting point and harden wax. All old candle holders have some form of catch plate or catch basin for drips. You can collect them and remelt them into new candles.
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JohnWW
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[*] posted on 9-7-2010 at 17:01


If the long-carbon-chain molecules in the wax have unsaturated double or triple bonds, cross-linking by adding across such bonds between molecules would increase the melting-point and hardness as the result of the increase in molecular weight and reduced ability of long carbon chains to slide past each other. However, it may be difficult to do this without simply adding across the double bonds to form 3-membered or other small rings within a molecule. Common ways to do this are by oxidation with a peroxy-acid such as peroxyacetic or peroxybenzoic acid which adds O atoms across the unsaturated bonds; and, similar to the "vulcanization" of rubber, by heating with sulfur which adds sulfur across the double bonds. Also if it has unsaturated long-carbon chains, catalytic hydrogenation would achieve a smaller increase in melting point.

[Edited on 10-7-10 by JohnWW]
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IrC
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[*] posted on 9-7-2010 at 17:10


Quote: Originally posted by JohnWW  
and by heating with sulfur which adds sulfur across the double bonds.


Not a chemical guru myself but when he burned the candles would not H2S be a possible outcome?




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[*] posted on 9-7-2010 at 18:27


Google Soy wax, and possibly stearic acid would harden vegitable tallows as it does paraffin wax....

Adding sulfur would produce choking fumes of SO2 as the candle burns...
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[*] posted on 9-7-2010 at 18:35


I remembered an old account where they said H2S was produced when a mixture of paraffin and flowers of sulfur burned, but I think you are right about the SO2. IIRC they had iron oxide in the mix. Now however I am curious if what they really made was SO2?




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[*] posted on 10-7-2010 at 09:32


I think if you heat sulfur and hydrocarbons without burning in O2 you get H2S.
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[*] posted on 11-7-2010 at 05:06


My guess is that palm wax contains a lot of different components, some will have higher melting points than others.
If you melt some wax then let it cool slowly the material with the highest melting point will be the first to solidify. If you let, say, half the wax set, then pour off the liquid then you will get two fractions, on with a slightly higher melting point than the other. You can repeat this process and you will get material with a higher melting point still; the problem is that you will not get much of it.
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watson.fawkes
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[*] posted on 11-7-2010 at 06:31


Quote: Originally posted by unionised  
If you melt some wax then let it cool slowly the material with the highest melting point will be the first to solidify.
Mixed plant-derived waxes are typically emulsified with each other, so it takes more effort to get them separated, such as using a centrifuge. It the present case something more like the centrifuge used in spin casting would be more appropriate than the benchtop style for test-tubes.
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[*] posted on 11-7-2010 at 12:59


I don't like the idea of trying to raise the melting point.. Generally, mixing in another component....Doesn't raise the melting point....It lowers it.

You could try dipping your palm wax candles, into a much higher melting wax. Coating them, so that the high melting coating acts as a dam or dike. Thereby forcing the elusive palm wax, to stay put, and fuel the flame....

Sort of like making a chocolate coated ice cream bar. Freeze your palm wax candles, give 'em a quick dip in a higher melting wax.....Then, quickly cool them again.
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trilly
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[*] posted on 20-2-2011 at 16:10


Quote: Originally posted by zed  
Generally, mixing in another component....Doesn't raise the melting point....It lowers it.
Google brought me to this thread because I am trying to do something similar as the OP. I make soy candles in glass containers, and I am trying to raise the melting point of the soy wax.

According to the manufacturer, the melting point of the wax is 113 - 119F/46 - 49C. If one wants to raise the melting point of this wax, the anecdotal advice has been to use additives such as stearic acid (advertised MP is 150 F/66C).

Zed, I don't doubt what you are saying about additives decreasing the overall melt point, but my question is, is that based on certain quantities and ratios? At what point would the overall melting point tilt from decreasing to increasing, if ever?

TIA
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[*] posted on 20-2-2011 at 20:20


Difficult.

Normally, I'd say hydrogenate it (saturation = higher mp). Unfortunately, palm wax is mostly palmitic acid TAG (C16:0) which has a low BP relative to stearic acid (C18:0), a previously recommended adjuvant (which I also believe will help).

Cheers,

O3





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