Abstract
The sulfonation of a pretreated fraction of spindle oil by 20% SO3-fuming sulfuric acid has been studied, and the effect of the reaction variables on the yield of mahogany acids has been investigated, in addition, their structure has been discussed.It has been found that with the more fuming sulfuric acid, at the higher temperature, and for the longer reaction time the yield of mahogany acid decreases, and with the higher velocity of stirring, the reaction rate increases.
In our experiments the most favourable condition of sulfonation of mineral oil may be as follows: quantity of fuming sulfuric acid is 20-30% (by volume) per oil, tempera-ture is at 30°Cand time is for 15minutes.However, the most important factor deter-mining the yield of mahogany acid is indeed the constituent of oil rather than reaction conditions.
From the ultraviolet and infrared absorption spectrum analyses, it is deduced that mahogany acid may be hydroxy aromatic monosulfonic acid with long paraffinic chain, of which hydroxy and sulfonic group are probably attached to aromatic ring. Mahogany acid may be produced by dehydrogenation of naphthene ring with following sulfonation.
The unreacted fraction contains some isomerized or intramolecular cyclized oil which are produced by the action of fuming sulfuric acid.
