The catalytic heat treatment of cottonseed oil to obtain drying oil characteristics

Abstract

Crude cottonseed oil was heat treated with four catalysts at various temperatures and lengths of time in an inert carbon dioxide atmosphere in an effort to impart drying oil characteristics to the oil. The tests were carried out in a three neck, 1000 ml., distilling flask heated electrically in a soy bean oil bath. The oil–catalyst mixture was agitated throughout each test.

One group of tests was made heating together 300 grams of crude cottonseed oil and 30 grams of silica bead catalyst for a duration of three, five, and eight hours at 120, 160, 200, and 240°C. A second group of tests was made heating together 350 grams of crude cottonseed oil and 35 grams of aluminum oxide for a duration of three, five, and eight hours at 160, 200, and 240°C. A third group of tests was made heating together 400 grams of crude cottonseed oil and 20 grams of magnesium oxide for a duration of three, five, and eight hours at 160, 200, and 240°C. and twelve hours at 200°C. A final group of tests was made heating together 300 grams of crude cottonseed oil and 30 grams of Raney nickel for a duration of three, five, and eight hours at 160, 200, and 240°C.

Iodine and acid numbers were determined for the products of each test. A sample of each of the products was mixed with turpentine and Japan drier, poured onto a glass strip, and allowed to dry. The times to become “set to touch” and “dry hard” were recorded. The appearance of each product was noted.

Tests using silica beads, aluminum oxide, and Raney nickel as catalysts did not impart drying oil characteristics to the oil. Some drying oil characteristics were exhibited by the products of the tests using magnesium oxide as a catalyst. When magnesium oxide and crude cottonseed oil were heated together for a duration of five and eight hours at 240°C and samples of the products mixed with turpentine and Japan drier, spread in a thin film on a strip of glass, the films were “set to touch” in 24 hours and “dry hard” in 36 hours.