Bp Chemicals Limited

William J Fox

Sean P O'Connor

John E Hamlin

Richard A'Court

The invention relates to an internal combustion fuel concentrate comprising: (a) from 1 to 95% of a chlorine-free carbamate prepared by reacting a carbamate of formula ##STR1## with a compound of the formula R OH (VI) in the presence of either a strone organic base or a tetra hydrocarbyl titanate so as to exchange the group R in formula (I) with a group R.sup.1 in formula (II), and (b) a fuel compatible solvent therefor. In the formula (I) R is a hydrocarbyl or substituted hydrocarbyl group and R.sup.1 is a hydrocarbyl or a hetero-substituted hydrocarbyl group different from R. In formula (I), X and Y are independently any of hydrogen, a hydrocarbyl group, or the group of the formula ##STR2## where Z is either a divalent hydrocarbyl, a substituted hydrocarbyl group or the group of formula

Carbamates, their production and use as fuels additives

A process for the production of a carbamate suitable for use as a detergent additive to internal combustion engine fuels which process comprises reacting either ammonia, a primary amime or a secondary amine with a dihydrocarbyl carbonate in the presence as catalyst of a strong organic base and in the proportions necessary to produce either a mono-carbamate or a bis-carbamate. A process for the production of a carbamate having formula (I), wherein X and Y are independently either hydrogen, a hydrocarbyl group or a hetero-substituted hydrocarbyl group or the group of formula (II), wherein Z is either a divalent hydrocarbyl, a substituted hydrocarbyl group or the group of formula (III) [alkytene)m(NH)n(alkylene)m] in which n=0 to 4 and m=1 to 4, and R is a hydrocarbly or substituted hydrocarbyl group, provided that if either one of X or Y is the group of formula (II), the other of X or Y is hydrogen, which process comprises reacting a compound of formula (IV), wherein X and Y are independently either hydrogen, a hydrocarbyl group or a hetero-substituted hydrocarbyl group with a dihydrocarbyl carbonate having formula (V), wherein independently R is as defined above in the presence as catalyst of a strong organic base and in the proportions necessary to produce either a mono-carbamate or a bis-carbamate.

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William J Fox