I am attempting to make urea formaldehyde resin by making a hexamine sol. adding sulphuric acid to make ammonium hydrogen sulphate and methanal at 30%
in the sol. then using this solution on very concentred urea sol. and ad few ml of conc H2SO4 and the mix dont want to polymerise. Do SM know why?
For formaldehyde I can only use hexamine as a starting material.
by making a hexamine sol. adding sulphuric acid to make ammonium hydrogen sulphate and methanal at 30% in the sol.
What is the reference?
I read it somewhere on this forum. Ammonia and methanal are reacted to make hexamine, ading an acid to the examine will hydrolise it back to
formaldehyde and an ammonium salt.
What was the reference used in that post and what reaction conditions are required?barley81 - 4-6-2012 at 10:49
Hmm... Methylamine HCl can be made by boiling hexamine and HCl. I don't expect the reaction of sulfuric acid and hexamine to cleanly produce
formaldehyde...
[Edited on 4-6-2012 by barley81]AndersHoveland - 4-6-2012 at 21:59
There is another family of resins that may hold interest to members here, and could be easily made.
Furfural is useful for forming resins, either by itself or with additives. It polymerizes under mildly acidic conditions to a dark colored polymer.
Interestingly, this new polymer still retains all it carbon-carbon double bonds. It is actually a condensation reaction, and water is released.
The furan rings become bridged by methylene groups attached on the carbon atoms of the ring adjacent to the oxygen in the furan ring. Apparently plain
furan cannot be readily polymerized, as it is more aromatic.
Since furfural is an aldehyde, it can also condense with amines to form resins, in a different type of reaction. US Patent 7781521 describes
furfural-urea resins. These resins can contain a range of different proportions, because the furfural does not need any urea to
polymerise.
