| 摘要 |
A process that employs a heterogeneous catalyst comprising a zinc aluminate mixed oxide and having the following formula: <?in-line-formulae description="In-line Formulae" end="lead"?>ZnAl<SUB>2</SUB>O<SUB>4</SUB>, xZnO, yAl<SUB>2</SUB>O<SUB>3 </SUB><?in-line-formulae description="In-line Formulae" end="tail"?> in which x and y each represent a number in the range 0 to 2, and in which the zinc aluminate is more particularly of the spinel type, makes it possible, by means of C1 to C5 monoalcohols, to: transesterify vegetable or animal oils having a natural free acidity, such as unrefined degummed rapeseed, soya, sunflower oils or exotic oils of the African oil, palm nut oil or coconut oil type, which are naturally rich in fatty acids; and simultaneously esterify their free acidity; so as to use phospholipid free and/or degummed unrefined acid oil with an acid number in the range 0.5 to 20, for example 1 to 15 and preferably 2 to 12, to produce esters, for example methyl esters, for use as fuels.
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