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Speight_Part II_B 11/7/01 3:11 PM Page 2.114

2.114 MANUFACTURE OF CHEMICALS
gives the corresponding ether. Reactions of butynediol with alkylene
oxides give ether alcohols.
In the presence of acid catalysts, butynediol and aldehydes or acetals
give polymeric acetals, useful intermediates for acetylenic polyurethanes
suitable for high-energy solid propellants.
HOCH C≡CCH OH → HO(CH C≡CCH OCH O) H
2 2 2 2 2 n
Electrolytic oxidation gives acetylene dicarboxylic acid (2-butyne-
dioic acid) in good yields. Butynediol can be hydrogenated partway
to butenediol (HOCH CH=CHCH OH) or completely to butanediol
2
2
(HOCH CH CH CH OH).
2
2
2
2
Addition of halogens proceeds stepwise, sometimes accompanied by
oxidation. Iodine forms 2,3-diiodo-2-butene-1,4-diol and, depending on
conditions, bromine gives 2,3-dibromo-2-butene-l, 4-diol, 2,2,3,3-tetra-
bromobutane-1, 4-diol, mucobromic acid, or 2-hydroxy-3,3,4,4-tetrabro-
motetrahydrofuran. Addition of chlorine is attended by more oxidation,
which can be lessened by esterification of the hydroxyl groups.
Butynediol is more difficult to polymerize than propargyl alcohol, but it
cyclotrimerizes to hexamethylolbenzene (benzenehexamethanol) with a
nickel carbonyl-phosphine catalyst or a rhodium chloride–arsine catalyst.