Simultaneous solvent extraction and transesterification of jatropha oil for biodiesel production, and potential application of the obtained cakes for binderless particleboard

• We investigate the biodiesel production directly from jatropha seeds.
• We investigate the binderless particleboard production from cakes as by-product.
• Increasing n-hexane and methanol to seed ratios will increase yield and quality.
• Increasing cakes moisture content will increase binderless particleboard quality.

This study investigated biodiesel production from jatropha seeds in a single step, i.e. by simultaneous solvent extraction and transesterification of jatropha oil, and possibility to transform the obtained cakes into binderless particleboards. n-Hexane was used as extracting solvent. The best operating conditions were identified to obtain optimal biodiesel yield and quality, and optimal physical and mechanical properties for binderless particleboards. Biodiesel yield was usually influenced by operating conditions, and the influences of both n-hexane to seed and methanol to oil ratios were most significant. An increase in n-hexane to seed ratio (from 1:1 to 3:1) combined with the decrease in methanol to oil ratio (from 13.3:1 to 8.0:1) led to an improvement in biodiesel yield. The best biodiesel yield (92% with a fatty acid methyl ester purity >98%) was obtained from 2:1 n-hexane to seed ratio, 10.6:1 methanol to oil ratio, 200–600 rpm stirring speed, 50 °C temperature and 6 h reaction time. Operating conditions had no significant effect on the biodiesel quality, except the n-hexane to seed ratio. Moreover, cohesive particleboards were produced from the obtained cakes, proteins and fibers acting respectively as binder and reinforcing fillers. An increase in the cake moisture content significantly improved the particleboard properties. The most promising binderless particleboard was manufactured from cake B under 20% cake moisture content and 160 °C pressing temperature. Its properties were 0.87 g/cm3 density, 8.4% moisture content, 7.2 MPa modulus of rupture, 10.4 GPa modulus of elasticity, 0.14 MPa internal bonding strength, 52% water absorption and 20% thickness swelling after 24 h immersion in water.