h i g h l i g h t sHigh induction period (IP) of 19.3 h for Moringa oleifera methyl ester. High antioxidant activity of the extract verified by DPPH method and voltammetry. Ethanolic extracts of M. oleifera leaves proposed as additives for biodiesel. The 98% (v/v) extract increased IP value of soybean biodiesel from 3.8 to 10.3 h. Efficiency of the extract was higher than TBHQ at the same concentration.
a b s t r a c tThis work reports the use of Moringa oleifera oil and leaves as potential sources for the production of biodiesel and antioxidant additives for biodiesels, respectively. The M. oleifera methyl ester was prepared by a two-step reaction and exhibited physical-chemical properties that met the minimum or maximum limits of the EN 14214, emphasizing the high induction period (IP) of 19.3 h. Ethanolic extracts of M. oleifera leaves were evaluated as additives to increase the IP value of biodiesels. The results indicate that the 98% (v/v) ethanolic extract increased IP values of soybean biodiesel from 3.8 to 10.3 h using the 100 lg g À1 of extract, showing better performance than the synthetic antioxidant tert-butyl-hydroquinone. The extract also provided similar efficiency to methyl esters produced from sunflower, colza, corn and residual cooking oils. These results evidence the promising use of M. oleifera not only for biodiesel production but also as a source of antioxidant additives for biodiesels with low oxidation stability.
h i g h l i g h t s " Galvanised and carbon steels have proven to be compatible with biodiesel. " Biodiesel properties were not affected for a storage time of 56 days. " Zinc release in non-stabilised biodiesel did not stimulate biodiesel deterioration. " TBHQ was rapidly consumed in the first days of the corrosion immersion test. " TBHQ acted as a corrosion inhibitor and enhanced storage stability of biodiesel.
a b s t r a c tThe storage stability and corrosive character of soybean biodiesel stabilised with tert-butylhydroquinone (TBHQ) was investigated through static immersion corrosion tests. Coupons of carbon steel and galvanised steel were immersed in soybean biodiesel with and without TBHQ for 12 weeks. Measurements of total acid number, peroxide value, oxidation stability (Rancimat induction period), metal release, and TBHQ consumption at different stages of corrosion were performed. After 12 weeks of the static immersion test with both steels, the non-stabilised biodiesels presented induction times below the EN 14214 limit (6 h); these results were in agreement with increase in the peroxide values. Zinc release was only detected in the non-stabilised biodiesel exposed to galvanised steel, whilst iron was not detected in any biodiesel samples exposed to carbon steel. The absence of zinc in the TBHQ-doped biodiesel exposed to galvanised steel indicates that TBHQ may have acted as a corrosion inhibitor. Additionally, TBHQ was rapidly consumed in the first 3 days of experiments, providing evidence of its activity. For a storage period of up to 56 days, both galvanised and carbon steels were shown to be compatible with biodiesel even in the absence of an antioxidant. The presence of zinc (>2 lg g À1 after 28 days of immersion) due to corrosion did not promote biodiesel deterioration.
This same law, published on January 13, 2005, introduced the biodiesel in the Brazilian energy matrix and expanded the administrative competence of the National Agency of Petroleum and Natural Gas (ANP), which became, since then, the National Agency of Petroleum, Natural Gas and Biofuels. Since the publication of the abovementioned law, ANP took over the assignment to regulate and supervise the activities related to production, quality control, distribution, sale and marketing of biodiesel and diesel-biodiesel blend [8]. The continued rise in the percentage of biodiesel added to diesel demonstrates the success of the National Program for Production and Use of Biodiesel and the experience accumulated by Brazil in production and large-scale use of biofuels, especially the biodiesel. 1.2. Aspects of the biodiesel market in Brazil According to the Monthly Bulletin of Renewable Fuels of the Ministry of Mines and Energy (MME), based on deliveries of auctions promoted by ANP, it shows that the estimated production in May 2012 was 173,000 m 3. The total of the year up to this month, the cumulative production was 958,000 m 3. The installed production capacity, in May 2012, stood at 6.092 million m 3 /year (507,000 m 3 /month) of which 88% is related to companies holding the social seal [9]. The Social Fuel Seal is a component of identification created from the Decree No.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.