Pengembangan proses pembuatan aditif pelumas zincdifattyalkyldithiocarbamate berbasis minyak nabati

Abstract

Dithiocarbamate is an organosulfur compound which has many functions and applications in the various industries. In the field of automotive and metal working, these compounds are used as additives lubricants, in agriculture as pesticides, in pharmaceuticals as an antioxidant. In this study, we synthesized Zinc-difattyalkyldithiocarbamates compounds using materials which were derived from vegetable oil. Furthermore, performance test of the synthesized product as antioxidant and antiwear-antifriction in lubrication system was carried out. Zinc-difattyalkyldithiocarbamates complexes were synthesized by reacting primary fatty amines with acyl chlorides formed secondary fatty amides, continued with reducing the corresponding product to secondary fatty amines using LiAlH4, and finally secondary fatty amines were reacting with ZnCl2 and CS2, to formed Zinc-difattyalkyldithiocarbamates. Each corresponding of product were successfully synthesized with range of yield were 10 to 87, 17 to 96, and 77 to 87% respectively. The synthesis of primary fatty amines to secondary fatty amides, secondary fatty amides to secondary fatty amines, and secondary fatty amines to Zincdifattyalkyldithiocarbamates complexes were evaluated from fourier transformation infra red (FTIR) spectrum quality with the wave number of 3300 cm-1 for NH vibration, 1639 cm-1 for C=O vibration, 1454 cm-1 for tioureida C-N vibration, 968 cm-1 for C-S vibration, and in the far infra-red area with the wave number of 387 cm-1 that showed the maximum absorption of M-S bond (sulfur metal). Besides using the FTIR spectrum, Zinc-difattyalkyldithiocarbamates complexes formation were also evaluated by Zinc-recovery test using atomic absorption spectrophotometer (AAS), and conformity purity test using high performance liquid chromatography (HPLC). All variants of Zinc-difattyalkyldithiocarbamates synthesized were done using rancimat test method and four ball test method to determine the antioxidant activity and antiwear-antifriction activity. At the same concentration of 125 ppm, all variants of product showed the antioxidant activity higher than the BHA, BHT, and commercial additives control. The highest antioxidant activity was obtained by three variants of the Zinc-bis(dilauryl)dithiocarbamate, Zincbis( laurylpalmityl)dithiocarbamate, and Zinc-bis(laurylstearyl)dithiocarbamate. At the same concentration of 1.2%, all variants of product showed the welding point higher than the lube base oil HVI 60 as base lubricants, and US Steel 136 as extreme pressure standard additive, but only Zincbis( laurylpalmityl)dithiocarbamate and Zinc-bis(lauryloleyl)dithiocarbamate showed load wear index higher than both of these base lubricants and standard. Zinc-bis(laurylpalmityl)dithiocarbamate was the best of antioxidant and antiwearantifriction additive compared to others homologous compounds of product. Conversion of crude palm oil to palmityc acid, palmytic acid to hexadecylamine, and hexadecylamine to Zinc-bis(laurylpalmityl)dithiocarbamate additive can increase the value of the product. With assumption, the cost of raw material as Rp.8.520,-/kg and the product value Rp.1.210.000,-/kg, therefore industry will able to generate added value with Rp.8.135,-/kg, and Rp.6.290,-/kg of company profit.

Ditiokarbamat merupakan senyawa organosulfur yang telah lama dikenal, dan diketahui banyak memiliki fungsi dan kegunaan. Di bidang pertanian, senyawa ini diantaranya digunakan sebagai pestisida, di bidang farmasi digunakan sebagai antioksidan, sedangkan di bidang industri otomotif dan pengerjaan logam digunakan sebagai aditif pelumas. Dalam penelitian ini dibuat senyawa Zincdifattyalkyldithiocarbamate menggunakan bahan baku fattyamina primer berbasis minyak nabati dan dikarakaterisasi fungsinya sebagai aditif antioksidan dan aditif antiaus-antifriksi dalam sistem pelumasan. Jalur proses pembuatan dimulai dari bahan baku fattyamine primer yang dikonversi ke fattyamide sekunder sebagai produk antara. Fattyamide sekunder selanjutnya direduksi menjadi fattyamine sekunder. Senyawa terakhir ini selanjutnya dikonversi menjadi kompleks Zinc-difattyalkyldithiocarbamate. Pembuatan fattyamide sekunder dan Zinc-difattyalkyldithiocarbamate dilakukan dalam reaktor tumpak terbuka tangki teraduk, sedangkan pembuatan fattyamine sekunder dilakukan dalam reaktor tumpak terbuka tangki teraduk, reaktor tumpak tertutup berpemicu gelombang mikro, dan reaktor tumpak tertutup syncore tangki teraduk.