ChrisWhewell
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surfactants
Whoever comes up with a way to controllably add EO or PO to a monoalkylated benzene wherein the alkyl chain is in the fatty acid range length, may
make themselves a fortune if they handle the business and IP side of things appropriately. Problem is, alkoxylations are outside the skill level of
most. I have what I think is one really danged good idea, but lack the facilities.....
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JohnWW
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By "EO"and "PO", do you mean ethylene oxide and propylene oxide, the two simplest epoxides? They do not appear to react directly with long-chain
monoalkylated benzenes, which are relatively unreactive, at all. Their principal ring-opening reactions under ordinary circumstances are: hydrolysis
with aqueous acids to form glycols (with phenols, if sufficiently acidic, they may form an ether with a vicinal -OH), and with primary or secondary
amines to form secondary or tertiary amines with a vicinal -OH group; and with Grignard reagents followed by acid hydrolysis to form a substituted
ethanol.
So to do that, i.e. adding a polar group to the ring of a long-chain monoalkylated benzene, and one that will react with a low-molecular-weight
epoxide, you would have to do something like a ring mono-nitration with HNO3 + H2SO4 (which is likely to form mostly the para-isomer which for
surfactant purposes would be the best, a much smaller amount of ortho-isomer, and a very small amount of meta-isomer), followed by reduction of the
-NO2 group to -NH2 with nascent H or with H2 catalytically. Then this aromatic amine could be reacted with an epoxide to form a secondary
amine/alcohol, which could then be oxidized to an amino-acid.
Alternatively, the aromatic amine formed as above could be reacted with NaNO2 and H2SO4 at low temperature to form a diazonium salt, and then this
heated to 100ºC with more H2SO4 to form a phenol and then this phenol (assuming it is sufficiently acid) reacted with the epoxide to form an
alkoxy-alcohol, which could be then oxidized to an alkoxy-substituted acetic acid
But would such molecules be good surfactants, compared with those already on the market?
[Edited on 29-12-09 by JohnWW]
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ChrisWhewell
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there's a ton of LAB available, that's used as precursor to the LAB sulfonates. If that stream could be used to make alkoxylated LAB, that would be
a winner. The problem is that in the presence of conventional catalysts such as AlCl3 instead of neatly adding repeated units of EO, PO onto the
ring, you get a mess instead. I'm not talking about ring openings or reaction with the side chain, just addiiton of EO or PO chains to the ring
itself in O and P positions. A useful process for producing a 1-alkyl, 2-polyalkoxy benzene material is worth a fortune.
[Edited on 29-12-2009 by ChrisWhewell]
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