Biodiesel Production From Tree Born Oil Using Bronsted-Lewis Acidic Ionic Liquid As Catalyst

In this study, aqueous enzymatic process assisted by microwave extraction of tree born oil was established. The fatty acids composition and main physicochemical properties of Camptotheca acuminata seed oil and yellow horn seed oil were determined. Moreover, Bronsted-Lewis acidic ionic liquid (IL) was prepared for catalyzing the transesterification reaction of biodiesel production. Microwave-assisted biodiesel production from tree born oil using the prepared IL as catalyst was established. In addition, main physicochemical properties of the biodiesel product prepared from Camptotheca acuminata seed oil and yellow horn seed oil were determined.1. Enzymatic pretreatment assisted microwave aqueous extraction of tree born oilThe enzyme cocktail of cellulase, hemicellulase and pectinase were immobilized using gel beads. Then immobilized enzyme cocktail was used for the enzymatic pretreatment of Camptotheca acuminata seed and yellow horn seed kernel, and the enzymatic pretreatment assisted microwave aqueous extraction of the both tree born oils was developed. The amounts of cellulase, hemicellulase and pectinase were determined, and the main factors, including pretreatment temperature and time, which affected the enzyme activity and pretreatment efficiency were optimized. Furthermore, the effects of extraction temperature, extraction duration, irradiation power and water to material ratio on the oil extraction yield were investigated.The optimal parameters of enzymatic pretreatment assisted microwave aqueous extraction of Camptotheca acuminata seed oil were as follow:Enzyme cocktail:cellulase2.5mg/g, hemicellulase1.9mg/g, pectinase1.3mg/gPretreatment temperature:40℃Pretreatment time:6hExtraction temperature:50℃Extraction duration:30minIrradiation power:500W Water to material ratio:5mL/gAn oil extraction yield of19.1%could be achieved under the above conditions.The optimal parameters of enzymatic pretreatment assisted microwave aqueous extraction. of yellow horn seed oil were as follow:Enzyme cocktail:cellulase1.8mg/g, hemicellulase1.3mg/g, pectinase2.5mg/gPretreatment temperature:40℃Pretreatment time:8hExtraction temperature:50℃Extraction duration:45minIrradiation power:500WWater to material ratio:6mL/gAn oil extraction yield of56.8%could be achieved under the above conditions.2. Determination of the fatty acid composition and main physicochemical properties of tree born oilThe fatty acid composition of Camptotheca acuminata seed oil and yellow horn seed oil were determined using GC-MS. A fast and accurate method was developed for the analysis of fatty acids composition of tree born oil.GC:Agilent VF-5ms silica capillary column (30m x0.25mm i.d.; film thickness0.25μn). Helium (99.99%) was used as carrier gas. The column temperature was initially50℃and then increased to170℃at20℃/min, held for3min, and finally increased to230℃at15℃/min. Injector and detector temperatures were250and280℃, respectively.MS:The mass spectrometer was operated in positive ion mode with ionization energy of70eV, and the ion source temperature was230℃. The split ratio was1:50. Mass units were monitored from m/z35to425.Under the above conditions, the fatty acid composition of Camptotheca acuminata seed oil was as follow:palmitic acid (5.03%), stearic acid (6.89%), oleic acid (10.14%), linoleic acid (26.58%), linolenic acid (45.21%) and eicosenoic acid (4.65%).The fatty acid composition of yellow horn seed oil was as follow:palmitic acid (5.27%), stearic acid (2.03%), oleic acid (30.40%), linoleic acid (42.12%), eicosenoic acid (10.09%), docosenoic acid (3.49%) and nervonic acid (4.44%).The main physicochemical properties of tree born oil were determined using GB/T standard methods.The main physicochemical properties of Camptotheca acuminata seed oil were as follow: relative density (0.93g/mL), refraction coefficient (1.470), water and volatile content (0.15%), acid value (20.7mg KOH/g), iodine value (128.3), saponification value (204.8mg KOH/g), peroxide value (1.62meq/kg) and average molecular weight (929.3).The main physicochemical properties of yellow horn seed oil were as follow:relative density (0.92g/mL), refraction coefficient (1.469), water and volatile content (0.10%), acid value (0.56mg KOH/g), iodine value (132.5), saponification value (185.7mg KOH/g), peroxide value (0.98meq/kg) and average molecular weight (909.1).3. Preparation of Bronsted-Lewis acidic IL for catalyzing the transesterification reaction of biodiesel productionA series of Bronsted-Lewis acidic ILs were prepared using Bronsted acidic IL with various metal sulfates for the first time, and [BSO3HMIM]HSO4-Fe2(SO4)3represented a superior catalytic activity. Acetonitrile, a weak Lewis base, was used to characterize the Lewis acidity of the prepared IL catalyst as the probe for FTIR analysis. Moreover, the catalytic mechanism of transesterification reaction using the prepared Bronsted-Lewis acidic IL was clarified. Clarifying the catalytic mechanism of the transesterification reaction demonstrated that the outstanding catalytic performance of the prepared Bronsted-Lewis acidic IL was based on the synergetic effect of its Bronsted and Lewis acidic parts with different catalytic mechanisms.4. Microwave-assisted biodiesel production from tree born oil using Bronsted-Lewis acidic IL as catalystMicrowave-assisted biodiesel production from tree bom oil using Bronsted-Lewis acidic IL as catalyst was developed, and the main factors, including reaction temperature, methanol/oil molar ratio and catalyst amount, which affected the conversion yield were optimized.The optimal conditions of microwave-assisted biodiesel production from Camptotheca acuminata seed oil were as follow:Reaction temperature:60℃Methanol/oil molar ratio:5Catalyst amount:4%oil massA conversion yield of96.7%could be achieved under the above conditions.The optimal conditions of microwave-assisted biodiesel production from yellow horn seed oil were as follow:Reaction temperature:60℃Methanol/oil molar ratio:8Catalyst amount:3%oil massA conversion yield of97.5%could be achieved under the above conditions.In addition, the main physicochemical properties of the biodiesel product preparaed from tree born oil were determined.The main physicochemical properties of the biodiesel product preparaed from Camptotheca acuminata seed oil were as follow:density (0.88g/mL), viscosity (4.2mm2/s), flash point (102℃), acid value (0.47mg KOH/g), sulfur content (0.03%), carbon residues (0.16%) and cetane number (55.3).The main physicochemical properties of the biodiesel product preparaed from yellow horn seed oil were as follow:density (0.87g/mL), viscosity (4.4mm2/s), flash point (165℃), acid value (0.03mg KOH/g), sulfur content (0.02%), carbon residues (0.06%) and cetane number (56.1).