Separation Of Polyunsaturated Fatty Acids (PUFAs) From Jatropha Curcas L. Seed Oil And Preparation Of Polyurethane Foam

Unsaturated fatty acids (UFAs) is a kind of essential fatty acid for human and important basic chmical raw material. However, the imperfect effect of UFAs isolation results from complicated compositions of fatty acids from natural oil. The major methods of UFAs separation are urea complexation, molecular distillation, lipase concentration, and so on. Although urea complexation method extensively uses in large-scale application of UFAs isolation, some difficulties still exist, such as a long cycle of separation, lower purity, and urea and urea-water solution recovery or disposition. Therefore, in this paper, polyunsaturated fatty acids (PUFAs) from Jatropha curcas L. seed oil was isolated via urea adduction fractionation, and a environmental cyclic technology of separating UFAs was obtained, solved the problems of urea and fatty acids recovery and reuse from urea inclusion compounds. At the same time, crude fatty acids and fatty acids separated by low temperature crystallization were utilized in polyurethane foam preparation. The main contents are studied as follows.1. Oil was extracted from Jatropha curcas L.seed with petroleum ether as extraction solvent. The suitable extraction process condition was solid-to-liquid of mass ratio1:4, 0.5 h for extraction at 70℃just once and the yield of oil was 94.47 %.2. Based on the results of single-factor selecting experiments, the preferable condition of saponification-acidifiction for Jatropha curcas L.seed oil was oil-water of mass ratio 2:1, ethanol-water of volume fraction 2:1, 1.5 h for saponification at 70℃. The average of yield, acid value and iodine value of fatty acid were 98.25 %, 203.7 mg/g and 109.9 g/100g. An excellent applicability of the hydrolysis technology was displayed through applicable experiments using cornus wilsoniana seed oil, tung oil, palm oil and soybean oil.3. The process route of purifying PUFAs from Jatropha curcas L. seed oil was established using low temperature crystallization and urea adduction fractionation method. Influencing factors of purification PUFAs have been studied, and the experimental results are just as followed: the amount of urea has great effect on purity and yield of PUFAs. It is useful to obtain different purity and yield of products by adjusting the dosages of urea and methanol. The content of PUFAs was increased with a decreased yield when the amount of urea was increased. With the rasing temperature, yield of PUFAs was increased, while purity was declined. It was also found that the slower cooling method could promote the yield of PUFAs compared with rapid cooling program. Meanwhile, the enrichment of PUFAs from five vegetable oil using urea complexation method under the same technological conditions were investigate. The best separation effect were displayed when PUFAs from palm oil and cornus wilsoniana seed oil were isolated, with high purity of above 96 %. The contents of PUFAs in Jatropha curcas L.seed oil and soybean oil were improved by 38 %. While unconspicuous effect of PUFAs in tung oil separation was depicted.4. A new technology of recovery using methanol-toluene binary solvent mixtures method was created to recover urea and fatty acids from urea inclusion compounds. And the high recovered yield of fatty acids (99.12 % )and urea (99.46 %) were obtained respectively, when the ratio of urea inclusion compounds - methanol - toluene was 1:3:3 (g:mL:mL). Recovered fatty acids was analysed using FT-IR and GC-MS. FT-IR spectroscopy identified the structure of recovery material, finding saturated and unsaturated fatty acids were contained. Six kinds of fatty acids were identifed and content of UFAs (93.96 %) detected in recovery fatty acids via GC-MS. As for recovery urea, long needle-like crystal structure was observed using microscope, indicating that recovery urea has higher crystallinity. The thermal analysis curves of urea and recovery urea share a similar trend just as TG-DSC-DTG analysis spectrograms displayed. That is to say, the purity of recovery urea closed to new urea and fatty acids and urea in urea inclusion compounds could be effectively recovered using methanol-toluene binary solvent. Finally, the results of recovery urea reused for isolating PUFAs six times were investigated, and the results of effects and repeatability in every time process of reused are as followed: the contents and yields of PUFAs purified by recovery urea were among 81~89 % and 60~72 %, respectively, indicated SFAs was contained completely.5. Compared the properties of polyester polyol from fatty acids which difference in iodine value and polyurethane foam(PUF) prepared with six kinds of polyols. It was found that iodine number of fatty acids (1#<2#<3#) effected on hydroxyl value of polyol. Hydroxyl value of 1#, 2# and 3# polyester polyol was 261.47, 370.28 and 434.49 mg·g-1, respectively. Polyester polyol was analysed with FT-IR and GPC. The result of FT-IR indicated that epoxidation, ring-opening reaction and esterifiction of fatty acids were complete. Polyol's relative molecular weight mostly distributed in 600~2000 with a content of 97 % were detected by GPC. Foam density determines the performance of mechanism, such as higher foam density tends to be better compress and bending property. Six kinds of foam's density are in the sequence ofρphthalic anhydride<ρ1#<ρrosin-based<ρ2#<ρpolyether<ρ3#. Proe structure of foam was observed by SEM. The SEM photograph showed that PUF of using 3#, rosin-based and polyether polyol have regular pentagon and hexagon structures with fine and well-distributed cell foam and non-shrinkage foam. While 2# foam had a slight shrink, 1# foam structure was irregular and easy contractile and surface of PUF using phthalic anhydride polyol was popcorn shaped. Finally, TG-DSC-DTG characterized heat-resistant quality of foams. Before heating temperature raised to 300℃, PUF of using 1#, 2#, 3#, rosin-based and polyether polyol kept their mass more than 90 % with excellent thermal stability. However, when the thermal decomposition was raised to 450℃, PUF using 1#, 2# and 3# polyester polyol (wt conseration rate >50 %) had better heat resistance than the other three kinds of foams(wt conseration rate <50 %).Thereform, this kind of fatty acid-based polyester polyol could be used as the heat endurance of polyol.