Development of Bifunctional Additives Derived from Cashew Nut Liquids for Application in Diesel/Biodiesel Blends.
Cardanol; LCC; LCC derivatives; fuel additives; antioxidant property; lubricity.
World concerns regarding environmental pollution and global warming have strengthened the search for alternative solutions to the consumption of oil and its derivatives. For this reason, biodiesel was introduced in the Brazilian energy matrix through the National Program for Biodiesel Production and Use (PNPB), whose objective is to implement its production and use it in a sustainable way, with a focus on social inclusion and regional development, also aiming to reduce the dependence on imports of fossil oil derivative, diesel oil. Biodiesel is used in the vehicular fleet through its insertion together with diesel, which has high oxidative stability when compared to biodiesel. However, in the diesel/biodiesel blend, the oxidation instability of biodiesel predominates, causing long term wear and/or corrosion in the mechanical devices of vehicles fueled with this combination. In this scenario, antioxidant agents stand out, from which cardanol, a by-product of the cashew nut processing industry and is present in the Cashew Nut Liquid (CNSL), is included. In this present project, the main objective was to evaluate the potential of cardanol and some of its derivatives as fuel additives, with antioxidant and lubricity properties. In that, eight LCC derivative additives (AD-LCC) were synthesized, such as: 3-pentadecylphenol (compound 1), 2-tert-butyl-5- pentadecylphenol (compound 3), 2-nitro-5-pentadecylphenol (compound 4), diethyl-3- pentadecylphenyl phosphate (compound 5), 3-pentadecylphenyl diphenyl (compound 6), tri (3-pentadecylphenyl) phosphate (compound 7), 2-tert-butyl-5-pentadecylphenyl diethyl phosphate (compound 8) and 2- tert-butyl-5-pentadecylphenyl diphenyl phosphate (compound 9). The AD-LCC/derivative compounds were characterized by Gas Cromatography Coupled to Mass Spectrometer (GC/MS) and by Infrared (IR) and Nuclear Magnetic Resonance (H1and C13 NMR) spectroscopies. The antioxidant activity of AD-LCC/derivative products, at concentration 2000 mg/kg was evaluated by DPPH• and Rancimat methods, in soy biodiesel synthesized in the laboratory and characterized according to ANP Resolution No. 45 of 08/25/2014. All AD-LCC/derivative compounds stabilized the DPPH• radical, from which compounds 1, 3, and 7 showed the highest percentages of free radical reduction (46.5, 81.1, and 43%, respectively). In the test via Rancimat, all AD-LCC/derivative compounds increased the induction time of soy biodiesel, where the largest increases correspond to compounds 3 (31%), 7 (32.8%) and 9 (31%). The lubricity of the additives AD-LCC was evaluated by the Four Ball technique, in the diesel/biodiesel mixture on the ratio 8:2, with satisfactory results, exception for compound 4, who showed no influence on the lubricity regime in the analyzed mixture. Comparatively, the AD-LCC/phosphorus derivatives were the most efficient and represent a class of eco-friendly synthetic compounds, so if commercialized, they will add biotechnological value to the fuel industries.