| 摘要 |
<p>This invention is a process for making a substituted carboxylated derivative by reacting a polyolefin in which at least 35 % of the unsaturated linkages are vinyl and/or vinylidene groups with a molar excess of an unsaturated carboxylic compound at an elevated temperature. The process comprises of (a) reacting in an initial mild stage the polyolefin with the carboxylic compound in the absence of any other acidic or catalytic additive at a temperature in the range from 140-202 °C until at least 30 % of the vinyl and/or vinylidene groups in the polyolefin have reacted with the carboxylic compound, and (b) continuing the reaction in a subsequent severe stage in which the temperature is allowed to rise at least 10 °C above the maximum temperature of stage (a) so that the temperature does not rise above 250 °C in this severe stage. A highly desirable hydrocarbyl substituted succinic anhydride is produced which has a lower apparent succinylation ratio and viscosity. Furthermore the level of insoluble tar formed in the product is significantly reduced.</p> |
