Due to its lower solubility, this work proposes the use of KHSO₄ as a re-usable heterogeneous catalyst in the dehydration of castor oil. Refined and degummed castor oil were considered to determine the effect of the purification level. Re-usability tests of the catalyst were performed in five consecutive experiments, under the same reaction conditions. Fresh and used catalysts were characterized by infrared spectroscopy (FTIR), thermal analyses (TGA and DTA) and acidity assays. The use of the KHSO₄ catalyst afforded the desired yields, easy separation, and recovery for further use, which allows low environmental impact and low cost. Ultimately, the best dehydrated oil was evaluated in the production of an alkyd resin. Drying castor oil (iodine value 127.46 g I₂/100 g) was obtained using KHSO₄ at 230 °C and 190 min. KHSO₄ catalyst can be re-used in the dehydration of castor oil with a low decrease in activity, i.e., a conversion of 81% was achieved after the 5th re-use. This activity loss can be compensated with a small addition of fresh catalyst. This slow deactivation of the catalyst was due to a decrease in its acidity, because KHSO₄ was partially and slowly transformed into K₂SO₄ and K₂S₂O₇ during the reaction, releasing water, SO₃, and SO_2. An alkyd resin was obtained from dehydrated castor oil, with an acid index lower than 10 mg KOH/g. This resin exhibits properties, such as Gardner color, nonvolatile compounds, and Garner viscosity, similar to a commercial resin. The film obtained from the dehydrated castor oil resin showed the same set-to-touch, dry-to-touch, dry-hard, and dry-to-handle times as those of a commercial resin.

由于其较低的溶解度，这项工作建议使用 KHSO ₄作为蓖麻油脱水中可重复使用的多相催化剂。考虑精制和脱胶蓖麻油来确定净化水平的影响。在相同的反应条件下，连续五次进行催化剂的重复使用性测试。新鲜和用过的催化剂通过红外光谱 (FTIR)、热分析 (TGA 和 DTA) 和酸度测定进行表征。KHSO ₄催化剂的使用提供了所需的产率、易于分离和回收以供进一步使用，这使得环境影响小且成本低。最终，在醇酸树脂的生产中评估了最好的脱水油。干燥蓖麻油（碘值 127.46 g I ₂/100 g) 是在 230 °C 和 190 分钟下使用 KHSO ₄获得的。KHSO ₄催化剂可重复用于蓖麻油脱水，活性降低较小，第5次重复使用后转化率为81%。这种活性损失可以通过添加少量新鲜催化剂来补偿。催化剂的这种缓慢失活是由于其酸度降低，因为在反应过程中KHSO ₄部分缓慢地转化为 K ₂ SO ₄和 K ₂ S ₂ O ₇，释放出水、SO ₃和 SO _2。以脱水蓖麻油为原料得到醇酸树脂，酸指数低于10mg KOH/g。这种树脂具有与市售树脂相似的特性，例如加德纳颜色、非挥发性化合物和加纳粘度。从脱水蓖麻油树脂获得的薄膜显示出与市售树脂相同的触感固化、触感干燥、干燥坚硬和干燥处理时间。