Heterogeneous catalysis is widely applied in industry due to important advantages it offers to chemical processes such as improved selectivity and easy catalyst separation from reaction mixture, reducing process stages and wastes. This is the reason why nowadays heterogeneous catalysts are being developed to produce biodiesel. Several catalytic materials have been showed in bibliography: acid solids capable to carry out free fatty acids esterification reaction, base solids which are able to carry out triglycerides transesterification reaction and bifunctional solids (acid–base character) which show ability to simultaneously catalyze esterification and transesterification reaction. This review discusses the latest advances in research and development related with heterogeneous catalysts used to produce biodiesel.

Recent developments on heterogeneous catalysts for biodiesel production by oil esterification and transesterification reactions: A review

Production of biodiesel from high-FFA neem oil and its performance, emission and combustion characterization in a single cylinder DICI engine

Effective conversion of non-edible oil with high free fatty acid into biodiesel by sulphonated carbon catalyst

Biodiesel production by esterification of oleic acid over zeolite Y prepared from kaolin

In developing countries like India where 70% of country's petroleum needs are met by import, energy security assumes significance in view of uncertainty of supply and increasing price of petroleum fuels. Fuels of bio origin not only provide energy security, but also reduce emissions of harmful pollutants and greenhouse gases and ensure rural upliftment by increasing employment in agricultural sector. India cannot afford to produce biodiesel from edible oil seeds as it is done in the American and European countries. Extensive focus has been given on producing biodiesel from non-edible sources, specifically from Jatropha. Discrepancies between the expectation and realities regarding Jatropha as a feedstock necessitate efforts for diversification of the feedstocks. Scientific research should therefore be directed towards oilseeds like Karanja, Sal, Mahua, Neem, etc. that are widely available and sustainable to the diverse socio-economic and environmental conditions of rural India. Among them the evergreen neem with its wide availability and various useful uses may be a potential feedstock for biodiesel production. In this paper attempts have been made to overview the morphology of neem tree, various useful uses, physical and chemical characteristics of neem oil and optimized production process for biodiesel production from neem oil.

Vijayalakshmi Ponnusamy

Papers

Removal of free fatty acid in Azadirachta indica (Neem) seed oil using phosphoric acid modified mordenite for biodiesel production