Low grade crude palm oil (LGCPO) presents as an attractive option as feedstock for biodiesel production due to its low cost and non-competition with food resources. Typically, LGCPO contains high contents of free fatty acids (FFA), rendering it impossible in direct trans-esterification processes due to the saponification reaction. Esterification is the typical pre-treatment process to reduce the FFA content and to produce fatty acid methyl ester (FAME). The pre-treatment of LGCPO using two different acid catalysts, such as titanium oxysulphate sulphuric acid complex hydrate (TiOSH) and 5-sulfosalicylic acid dihydrate (5-SOCAH) was investigated for the first time in this study. The optimum conditions for the homogenous catalyst (5-SOCAH) were determined as: 1.5 wt% of acid catalyst dosage, 60 °C reaction temperature, 8:1 methanol molar ratio at 60 min. For the heterogeneous TiOSH, higher catalyst dosages such as 7% wt% is required with a methanol loading of 10:1 (molar ratio) at 120 min to decrease the initial FFA to less than 3%. Under these optimum conditions for both types of catalysts; the FFA levels were reduced from 11.3 % to less than 3 %, individually. This study introduces for the first time two types of acidic catalysts with high catalytic activity for the esterification of FFA content in low grade oils for biodiesel production which could be used for the treatment of a wide range of low quality oils.

低品位毛棕榈油 (LGCPO) 因其低成本和不与食品资源竞争而成为作为生物柴油生产原料的有吸引力的选择。通常，LGCPO 含有高含量的游离脂肪酸 (FFA)，由于皂化反应，无法在直接酯交换过程中进行。酯化是降低 FFA 含量和生产脂肪酸甲酯 (FAME) 的典型预处理过程。本研究首次研究了使用两种不同的酸催化剂对 LGCPO 进行预处理，例如硫酸氧钛复合水合物 (TiOSH) 和 5-磺基水杨酸二水合物 (5-SOCAH)。均相催化剂（5-SOCAH）的最佳条件确定为：酸催化剂用量的1.5wt%，反应温度60℃，8：1 甲醇摩尔比在 60 分钟。对于非均相 TiOSH，需要更高的催化剂剂量，例如 7% wt%，在 120 分钟时甲醇负载量为 10:1（摩尔比），以将初始 FFA 降低到小于 3%。在这两种催化剂的最佳条件下；FFA 水平分别从 11.3% 降低到不到 3%。本研究首次介绍了两种具有高催化活性的酸性催化剂，用于生物柴油生产中低级油中 FFA 含量的酯化，可用于处理各种低质量油。FFA 水平分别从 11.3% 降低到不到 3%。本研究首次介绍了两种具有高催化活性的酸性催化剂，用于生物柴油生产中低级油中 FFA 含量的酯化，可用于处理各种低质量油。FFA 水平分别从 11.3% 降低到不到 3%。本研究首次介绍了两种具有高催化活性的酸性催化剂，用于生物柴油生产中低级油中 FFA 含量的酯化，可用于处理各种低质量油。