NONIONIC EMULSIFIERS BASED ON STABILIZED POLIOXIETHYLENE-SORBITANS
In the present work is studied the synthesis of a nonionic emulsifier and its use for the
preparation of emulsified fuels. The nonionic emulsifier is an ester and it was prepared in two
ways: the addition of chemical compounds containing active hydrogen (esters obtained out of
fatty acids and sorbitol) to an oxyran (ethylene-oxide); the transesterification of the ethoxylated
sorbitol with the methylic ester of a fatty acid (oleic acid). The products obtained were further
purified through a patented procedure, to obtain stabilized compounds. The ester of oleic acid
with sorbitol was obtained by the transesterification of the sorbitol with methyl oleat. The
product content of oxiethylenic groups was 20-40 relative to a sorbitol molecule. The
synthesized emulsifiers were tested for the preparation of emulsified
oil-in-water fuels used for burning processes improvement and implicitly reductions of
pollutants.
Introduction
The policondensation of a compound containing hydroxilic groups (alcohol, poliol,
alkylphenol, carboxylic acid) with ethylene oxide can be schematically represented through
the following chemical reactions:
R – OH + CH2 – CH2 ——– > RO – CH2CH2 – OH (1)
\ /
O
RO – CH2 – CH2 – OH + n (CH2 – CH2) ——> RO – (CH2 – CH2 – O) n + 1 H (2)
\ /
O
The policondensation reactions can occur non-catalytically, at a high temperature and
pressure, or catalytically, in the presence of alkaline hydroxids or strong acids, at moderate
temperatures and pressures. The usage of acid catalysts is limited by the production of
polialkylglycolls which have small molecular weights and a very large distribution of the
molecular weights.
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