Ravulapalli Sujitha, Kunta Ravindhranath, Ramamoorty Mylavarapu
Department of Chemistry, Koneru Lakshmaiah Educational Foundation Green Fields, Vaddeswaram - 522 502, Guntur District Andhra Pradesh India
Department of Electrical and Electronics Engineering, Koneru Lakshmaiah Educational Foundation Green Fields, Vaddeswaram - 522 502, Guntur District Andhra Pradesh India.
RSC Adv. 2019 Jan 24;9(6):3311-3319. doi: 10.1039/c8ra08378a. eCollection 2019 Jan 22.
The methyl ester of Sesbania seed oil (MESSO) was prepared using the transesterification method. The conditions for obtaining the maximum yield of the ester were optimized. The yield was 93.3% (v/v) at reaction time of 24 h, catalyst concentration of 4.5 wt% and methanol to oil volume ratio of 6 : 1. MESSO was characterized by adopting TG-DTA and FT-IR methods. The physical, chemical and electrical properties were measured as per International Standards for assessing its suitability as an insulating liquid in transformers. The kinematic viscosity of the ester is 0.98 × 10 mm S, which is far less than the viscosity of the raw oil. The low acid/neutralization value (0.001 mg of KOH per g) for MESSO offers high oxidation stability. The high flash point (260 °C) and fire point (345 °C) values of MESSO provide operational safety to the transformers when they are filled with the developed insulating fluid. The saturated fatty acid content in MESSO provides a high thermal and oxidation stability for the transformers. The high dielectric constant values for MESSO in comparison to the mineral oil are attributed to the polar groups present in the ester. These results confirm that MESSO can be developed as an alternative to mineral oils for insulation and cooling in transformers. MESSO has merits of low cost, bio-degradability, ecofriendliness and preparation from renewable sources.
采用酯交换法制备了田菁籽油甲酯（MESSO）。对获得最大酯产率的条件进行了优化。在反应时间24小时、催化剂浓度4.5 wt%、甲醇与油体积比6∶1的条件下，产率为93.3%（v/v）。采用TG-DTA和FT-IR方法对MESSO进行了表征。按照国际标准测量了其物理、化学和电气性能，以评估其作为变压器绝缘液体的适用性。该酯的运动粘度为0.98×10 mm²/S，远低于原油的粘度。MESSO的低酸/中和值（每克0.001毫克氢氧化钾）具有高氧化稳定性。MESSO的高闪点（260℃）和燃点（345℃）值为填充了所开发绝缘流体的变压器提供了运行安全性。MESSO中的饱和脂肪酸含量为变压器提供了高的热稳定性和氧化稳定性。与矿物油相比，MESSO的高介电常数归因于酯中存在的极性基团。这些结果证实，MESSO可作为变压器绝缘和冷却用矿物油的替代品开发。MESSO具有成本低、生物可降解、生态友好以及可由可再生资源制备等优点。
