Why Does Polymerisation Occur in Diols?

  • Thread starter Thread starter jsmith613
  • Start date Start date
AI Thread Summary
HO-R-OH, where R represents an alkyl group, can polymerize due to the unique behavior of geminal diols compared to other diols. The polymerization is particularly effective when the diols are on the same carbon, leading to the formation of polyformaldehyde, which is a white powder with limited water solubility and can depolymerize back into a formaldehyde solution. Under acidic conditions and with the removal of water, polyethers can be synthesized from vicinal diols with longer alkyl chains, which include more than one methylene group. However, for shorter alkyls with 2 to 5 intervening methylenes, the reaction tends to yield complex mixtures of dimers, trimers, and cyclized monomers due to the volatility of intermediates formed during the reaction. This complexity arises because geminal diols exhibit distinct reactivity compared to other diols, significantly influencing the polymerization process.
jsmith613
Messages
609
Reaction score
0
why does
HO-R-OH
(where R is an alkyl group) polymerise?
i.e: with itself?
 
Chemistry news on Phys.org
How many carbons in that "alkyl" group?
 
chemisttree said:
How many carbons in that "alkyl" group?

This extremely important, since only the simplest case of the diols existing on the same carbon are readily polymerized to poly acetals (geminal diol). The simplest is polyformaldehyde, a white powder that is poorly soluble in water with reaction to depolymerize to a formaldehyde solution.

One can envision under acidic conditions and with removal of H2O to drive the reaction, that poly ethers can be made for other alkyls of longer than one methylene (vicinal diols and greater intervening methylenes). For the shorter alkyls, (2,3,4, and 5 intervening methylenes), dimers, trimers, and the monomer can cyclize and remove intermediates (volatile under the conditions of reaction heat and H2O removal) needed to make longer polymers so complex mixtures result.
 
Last edited:
That's why I asked the question. Geminal diols behave very differently than other diols.
 

Thread 'Humidity of a saturated NaCl solution with anticaking additive'

I want to test a humidity sensor with one or more saturated salt solutions. The table salt that I have on hand contains one of two anticaking agents, calcium silicate or sodium aluminosilicate. Will the presence of either of these additives (or iodine for that matter) significantly affect the equilibrium humidity? I searched and all the how-to-do-it guides did not address this question. One research paper I found reported that at 1.5% w/w calcium silicate increased the deliquescent point by...
View full post »

Thread 'Why does having 8 valence electrons make an element inert?'

I was introduced to the Octet Rule recently and make me wonder, why does 8 valence electrons or a full p orbital always make an element inert? What is so special with a full p orbital? Like take Calcium for an example, its outer orbital is filled but its only the s orbital thats filled so its still reactive not so much as the Alkaline metals but still pretty reactive. Can someone explain it to me? Thanks!!
View full post »

Thread 'Resists for etching Aluminium with NaOH'

I'm trying to find a cheap DIY method to etch holes of various shapes through 0.3mm Aluminium sheet using 5-10% Sodium Hydroxide. The idea is to apply a resist to the Aluminium then selectively ablate it off using a diode laser cutter and then dissolve away the Aluminium using Sodium Hydroxide. By cheap I mean resists costing say £20 in small quantities. The Internet has suggested various resists to try including... Enamel paint (only survived seconds in the NaOH!) Acrylic paint (only...
View full post »

Similar threads

Why -OR has more -I effect than -OH
Replies
1
Views
2K
Chemistry Conformation Stability of Ethane-1,2-Diol
Replies
1
Views
2K
Which Cyclohexane-1,2- or 1,3-Diol Isomer is Most Stable?
Replies
8
Views
2K
Silica gel polymerisation modeling
Replies
1
Views
3K
Neucleophilic Acyl substitution of unsymmetrical Acid Anhydrides
Replies
1
Views
5K
Contradiction of Gibbs adsoprtion?
Replies
2
Views
2K
Why anhydrous ZnCl2 is used in Groove's Process?
Replies
1
Views
11K
Alkyl Groups: Why is C2 an Alkyl Group?
Replies
1
Views
2K
Why Does Reactivity Differ in Group 7?
Replies
2
Views
2K
IUPAC Nomenclature: 3-Chlorobutane-1,2-diol
Replies
4
Views
2K

Hot Threads

Recent Insights

Back
Top