Hydroquinone → 2-Ethyl-2-(hydroxymethyl)propane-1,3-diol;prop-2-enoic acid

Participants

Reaction Steps

In a 10 l three-necked flask with a stirrer, a water separator and a gas inlet tube, 2.44 kg of trimethylolpropane, 3.93 kg of acrylic acid, 0.5 kg of an acid ion exchanger (Lewatit 3333 from Bayer AG), 9 g of hydroquinone and also 19 g of styrene together with 1.5 l of petroleum ether (boiling range 60°-70° C.) were heated, whilst stirring, under the water separator. During the esterification a slow stream of air was passed through the reaction. After 80 hours, the reaction mixture had an acid number of 32 and the boiling point had risen to 72° C. The petroleum ether was distilled off, residues being removed by applying a vacuum of 0.2 mm Hg at a product temperature of 40° C. The esterification catalyst was separated off by filtration. The trimethylolpropane tris-acrylate, which was obtained in almost quantitative yield, was pale yellowish and clear. The viscosity corresponded to a flow time of 20 seconds, measured according to DIN 53,211 in a DIN cup 4, at 20° C. Even when stored for 4 months at 60° C., the product showed no change. When used in a printing ink, which can be cured by UV light, and which contained a photoinitiator, the product polymerised at a high rate.

Provenance & Evidence