麻疯树籽油超声波辅助酯交换反应的研究

以野生植物麻疯树籽油为原料,经脱胶、脱酸及脱水处理后进行超声波辅助酯交换反应,在超声波频率25 kHz,反应温度65℃,催化剂用量为油重的1.0%,醇油摩尔比7∶1,反应时间60m in条件下,麻疯树籽油酯交换转化率达到93.79%。在相同反应时间内和相同醇油摩尔比条件下,超声波辅助酯交换反应比无超声波反应的酯交换转化率高,同时也降低了催化剂的用量。     

Analysis of parameters and interaction between parameters of the microwave-assisted continuous transesterification process of Jatropha oil using response surface methodology

A simple continuous process was designed for the transesterification of Jatropha curcas (J. curcas) oil to alkyl esters using microwave-assisted method. The product with purity above 96.5% of alkyl ester is called the biodiesel fuel. Using response surface methodology, a series of experiments with three reaction factors at three levels were carried out to investigate the transesterification reaction in a microwave and conversion of alkyl ester from J. curcas oil with NaOH as the catalyst. The results showed that the ratio of methanol to oil, amount of catalyst and flow rate have significant effects on the transesterification and conversion of alkyl ester. Based on the response surface methodology using the selected operating conditions, the optimal ratio of methanol to oil, amount of catalyst and flow rate of transesterification process were 10.74, 1.26 wt% and 1.62 mL/min, respectively. The largest predicted and experimental conversions of alkyl esters (biodiesel) under the optimal conditions are 99.63% and 99.36%, respectively. Our findings confirmed the successful development of a two-step process for the transesterification reaction of Jatropha oil by microwave-assisted heating, which is effective and time-saving for alkyl ester production.     

Effect of low frequency ultrasonic assisted extraction on the quality of seed oils of Indian origin

The study gives an insight into the effect of low frequency ultrasonic enhancement of solvent extraction on the quality of non-edible oils (Jatropha and Pongamia as model seed varieties) in comparison to conventional methods of extraction i.e. direct reflux or soxhlet extraction using hexane. A series of experiments have been carried out to study the effect of variables; solute to solvent ratio (1:2.5-1:10) and reaction time (30 s-60 min) on the yield of oil. The quality of oil extracted by different methods have been assessed by determining the acid value of oil by ASTM D-974/04 method, a measurement of triglyceride and fatty acid degradation, by the presence of phorbol esters in Jatropha curcas and phenolic compounds in Pongamia oil analyzed using HPLC. Under optimized conditions solute to solvent ratio of 1:10 (w/v), 3 min extraction time yields > 95% pure oil having < 1% FFA in Jatropha curcas and 30 s extraction time in Pongamia seed yields oil with less than 2% FFA in comparison to conventional method of extraction in 16 h.     

Polyphenolic Contents and Antioxidant Potential of Stem Bark Extracts from Jatropha curcas (Linn)

We assessed the polyphenolic contents and antioxidant potential of the aqueous, ethanol and methanol stem bark extracts of Jatropha curcas. The total phenol, flavonoids, flavonols and proanthocyanidin contents of the extracts were evaluated to determine their effect on the antioxidant property of this plant, using standard phytochemical methods. The antioxidant and free radical scavenging activity of ethanol, methanol and aqueous extracts of the plant were also assessed against 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), ferric reducing, nitric oxide (NO), superoxide anion, (O(2) (-)) and hydrogen peroxide (H(2)O(2)) using spectroscopic methods and results were compared with that of butylated hydroxyl toluene (BHT) and ascorbic acid as standards. The concentrations of different classes of phenolic compounds were higher in methanol and ethanol extracts compared to aqueous extracts. There was correlation between total phenol, total flavonoids, total flavonol and total proanthocyanidins (r = 0.996, 0.978, 0.908, and 0.985) respectively. There was correlations between the amount of phenolic compounds and percentage inhibition of DPPH radicals scavenging activity of the extract (r = 0.98). Findings from the present study indicated that J. curcas is a potential source of natural antioxidants and may be a good candidate for pharmaceutical plant based products.     

Biophysicochemical evaluation and micropropagation study of Jatropha curcas L. collections for biodiesel production

Jatropha curcas, a member of the Euphorbiaceae family, is an upcoming energy source, which promises to mitigate the energy crisis and environmental pollution. Jatropha curcas oil is looked up in terms of availability and cost and also has several applications and enormous economic benefits. The seed oils of five Jatropha curcas biotypes were screened and evaluated for their physiochemical parameters, viz. oil content (20–43%), biodiesel yield (48–66%), density (.866–.969 g/cm³), viscosity (50.12–93.79 mm³/s), iodine value (232.738–457.16 mg/g), free fatty acid (18.847–7.614 mg/g), saponification value (59.29–93.79 mg/g), flash point (125–220°C), fire point (155–260°C) and ash content (.19–.399%), which were estimated for selection of the elite Jatropha curcas biotype. The best shoot regeneration (60%) was observed in Murashige and Skoog (MS) medium supplemented with naphthalene acetic acid (0.5 ppm) and benzyl amino purine (2.0 ppm). Root induction (90%) was successfully obtained in plain MS. Acclimatisation and hardening was quite successful with survival rate of 70%.     

Kinetic studies on the esterification of free fatty acids in jatropha oil

Kinetic studies have been carried out on the esterification of free fatty acids (FFAs) in jatropha oil with methanol in the presence of sulphuric acid catalyst at 5 and 10 wt% concentrations relative to free fatty acids (0.4–0.8 wt% relative to oil) and methanol–FFA mole ratios ranging from 20:1 to 80:1. It has been found that a 60:1 methanol–FFA mole ratio and 5 wt% catalyst at 60°C and 500 rpm or above provided a final acid value lower than 1 mg KOH/g oil within 60 min. A kinetic model has been proposed with second‐order kinetics for both the forward and backward reactions. The effect of temperature on the reaction rate constants and equilibrium constant has been determined using Arrhenius and von't Hoff equations, respectively. The heat of reaction was found to be ?11.102 kJ/mol.     

SPRERI experience on holistic approach to utilize all parts of Jatropha curcas fruit for energy

Freshly harvested Jatropha dried fruit contains about 35–40% shell and 60–65% seed (by weight). The fruits are 2.5 cm long, ovoid, black and have 2–3 halves. It has nearly 400–425 fruits per kg and 1580–1600 seed per kg weight. Weight of 100 seeds is about 63 g. Jatropha shells are available after de-shelling of the Jatropha fruit while Jatropha seed husks are available after decortications of Jatropha seed for oil extraction. Seed contains about 40–42% husk/hull and 58–60% kernels. The kernels have about 50% oil. If the oil is extracted by solvent method the oil recovery is more than 95% but in mechanical expeller the oil recovery is about 85% only. If 100 kg of seed is expelled by expeller it will give about 28–30 kg oil. While lot of emphasis is being given on use of bio-diesel, which is only about 17–18% of the dry fruit, not much attention is being given to utilize other components of fruit for energy purposes.At SPRERI holistic approach has been taken to utilize all components of the Jatropha fruit—shell for combustion, hull/husk for gasification, oil and bio-diesel for running CI engines, cake for production of biogas and spent slurry as manure and it has been found that all components of the Jatropha curcas fruit can be utilized efficiently for energy purposes. This paper gives detailed information on the use of different components of J. curcas fruit for energy purposes.     

Bio‐diesel lubricity: correlation study with residual acidity

Bio‐diesel has been accepted as a renewable liquid biofuel worldwide. In order to ensure customers' acceptance, standardisation and quality assurance are the key factors to the market introduction of bio‐diesel as a transport fuel. Lubricity of bio‐diesel is an important issue and it is well reported that 1–2% bio‐diesel is sufficient to maintain the lubricity of diesel even of very poor lubricity. However, a wide variation in lubricity performance of bio‐diesel from different vegetable oils and sources has been noticed. In addition, on critical examination, it was noticed that the variation in the lubricating performance of bio‐diesel could be better linked to its residual acidity than to variation in fatty acid composition. Copyright © 2007 John Wiley & Sons, Ltd.     

Jatropha curcas: A potential crop for phytoremediation of coal fly ash

A greenhouse pot experiment was conducted to test the heavy metal phytoremediation capacity of Jatropha curcas from fly ash. Both natural accumulation by J. curcas and chemically enhanced phytoextraction was investigated. Plants were grown on FA and FA amended with fertile garden soil, in presence and absence of chemical chelating agent EDTA at 0.1 g kg⁻¹ and 0.3 g kg⁻¹ of soil. EDTA enhanced the uptake of all five elements (Fe, Al, Cr, Cu and Mn) tested. Fe and Mn were retained more in roots while Cu, Al and Cr were translocated more to the shoot. Metal accumulation index indicates that the effect of EDTA at 0.3 g kg⁻¹ was more pronounced than EDTA at 0.1 g kg⁻¹ in terms of metal accumulation. Biomass was enhanced up to 37% when FA was amended with GS. Heavy metal uptake was enhanced by 117% in root, 62% in stem, 86% in leaves when EDTA was applied at 0.3 g kg⁻¹ to FA amended with GS. Study suggest that J. curcas has potential of establishing itself on FA when provided with basic plant nutrients and can also accumulate heavy metals many folds from FA without attenuating plant growth.