A 5 L-nitrogen-dried Büchi reactor, fitted with a mechanical stirrer, a sampling dip-leg, a vent, a rupture disk, a pressure sensor, a thermocouple well and a nitrogen inlet tube, was charged with propylene tetramer (2000 g, 1.75 eq.) and maleic anhydride (677 g, 1.0 eq.). The maleic anhydride was added as a solid (crushed briquettes from Aldrich) at room temperature. The reactor was then sealed and flushed with nitrogen for 5-10 min (5 psi of nitrogen was left in the reactor) before heat was applied. The mixture was heated up to 225-230° C. while stirring at 1000 rpm, the stirring being initiated when the reaction temperature had reached 55-60° C. The pressure built-up in the reactor was monitored with time and temperature (Pmax=54 psi). Sampling was performed during the course of the reaction until the desired conversion (followed by GC) with respect to maleic anhydride was achieved. After 4.5 hours of reaction, the reaction mass was cooled to 95° C. Butadiene (162 g; supplied by Matheson) was fed into the cooled reaction mixture through the inlet tube. After the butadiene addition, stirring was resumed without applying any additional heat. After two hours of reaction GC analysis showed that the maleic anhydride had been completely reacted. The contents of the reactor at a temperature of 55° C. were then discharged to a nitrogen-padded sample bottle while venting it with nitrogen. Analysis of the crude reaction mixture showed that it contained 54.96 wt % of DDSA, 5.68 wt % of THPA, 39.35 wt % of propylene tetramer and 0.01 wt % of maleic anhydride. Thus the weight ratio of the DDSA to THPA in this crude product was approximately 9.7:1. Unreacted starting materials (mostly residual olefin) were removed by flash distillation under reduced pressure using Kügelrohr equipment at an applied vacuum of 14.8 mmHg. After this purification, the product was a light yellow colored liquid.
