竹浆纳米纤维素制备工艺优化分析

响应面法优化超声波辅助酸水解制备竹浆纳米纤维素工艺条件,结果表明纳米纤维素优化制备工艺条件为超声时间22min,反应温度49．46℃,反应时间3．25h。优化条件下纳米纤维素得率平均为49．92％,与响应面法纳米纤维素得率预测值50．08％相接近。影响纳米纤维素得率的因素依次为反应时间、超声时间和反应温度。     

菜籽油油脚—皂脚复合裂解清洁工艺研究

提出菜籽油油脚－皂脚水解－醇解、皂化复合裂解清洁工艺。得到的最佳工艺条件为：水解温度１９０℃,水解时间１２ｈ,水与油脚－皂脚体积比３：１,黑脚醇解－皂解时间８ｈ．脂基裂解率９８％,脂肪酸得率９６％,芥酸质量分数达８５％。     

从“中间层”回收脂肪酸

由棉油皂脚制取脂肪酸通常采用皂化、酸化法或酸化、水解法。国外先进的油脚脂肪酸生产工艺一般采用皂脚酸化、静置分层、水洗和离心分离等方法,然后再进一步加工离心分离得到的酸性油(包括水     

微波条件下纤维素在磷酸中的快速水解

微波条件下磷酸快速水解纤维素得到葡萄糖,而葡萄糖可替代甲醛制备新型环保PF(酚醛树脂)。以微波功率、反应时间和反应温度为试验因素,以葡萄糖产率为考核指标,采用正交试验法优选出磷酸水解纤维素的最佳工艺条件。结果表明:各因素对磷酸水解纤维素的影响依次为反应温度>反应时间>微波功率;当微波功率为240 W、反应温度为100℃和反应时间为40 s时,水解液中葡萄糖含量为80.7%,葡萄糖浓度为40.35 g/L;超声波能加快纤维素在磷酸中的溶解速率,常温时纤维素完全溶解在磷酸中需要72 h,而微波条件下纤维素完全溶解在磷酸中只需2 h。     

棉油皂脚脂肪酸合成二聚酸的研究

以棉油皂脚脂肪酸为原料,采取间歇常压聚合法合成二聚酸。应用正交实验考察了反应温度、催化剂和反应时间对二聚反应产物收率的影响。     

脱臭馏出物乙酯化影响因素及动力学研究

发散式超声强化大豆油脱臭馏出物与乙醇反应制备脂肪酸乙酯具有反应过程温和,原料成本低廉,反应速率快等优点。文中对其过程影响因素及反应动力学特性进行研究。结果表明:在超声功率150 W,反应温度80℃,醇油体积比90∶100,催化剂用量(质量分数) 1. 6%,反应时间2 h的实验条件下,脂肪酸乙酯得率可以达到90. 6%。酯化过程为二级反应,在超声功率为90 W和150 W时,活化能分别为37. 10 kJ/mol和47. 43 kJ/mol;反应速率常数分别为0. 097 07和0. 245 22。通过提高超声功率,可以有效强化大豆油脱臭馏出物酯交换过程,加快反应速率,缩短反应时间。     

超声波辅助合成反式二苯乙烯

报道了一种在超声波辅助条件下,基于McMurry反应合成反式二苯乙烯的新方法。采用单因素实验,研究了超声波辅助条件下TiCl_4/锌粉用量、反应温度、反应时间及超声功率对反应收率的影响,筛选得到了优化的合成条件。在优化合成条件下完成了21种反式二苯乙烯类化合物的超声波辅助合成,采用FT-IR、EI-MS、~1HNMR、~(13)CNMR等表征手段对产物进行了结构确证。研究表明,该方法可有效减少TiCl_4/锌粉及溶剂用量、缩短反应时间、提高反应收率,并且具有较广的底物适用性。     

芦苇浆纳米纤维素的微波辅助酸水解制备优化

采用响应面法优化微波辅助酸水解制备芦苇浆纳米纤维素工艺条件,结果表明纳米纤维素优化制备工艺条件为微波时间为10 min,反应温度为54.61℃,反应时间为3.02 h。优化条件下纳米纤维素得率平均为55.67%,与响应面法纳米纤维素得率预测值55.49%相接近。影响纳米纤维素得率的因素依次为微波时间、反应温度和反应时间。     

超声波法制备纳米硫酸钡的研究

研究了超声波法制备纳米硫酸钡,考察了反应物浓度、超声功率、反应时间、反应温度等条件对产物粒径的影响,并用激光粒度分析仪和TEM对其进行了分析和表征。结果表明,当超声功率比为40%、反应物浓度为0.25 mol/L、超声反应15 min时,超声反应温度30℃为最佳条件,硫酸钡粒径最小。     

超声波法黄原酸化壳聚糖的制备

介绍了制备黄原酸化壳聚糖(XCTS)的常规方法和超声波法, 使用元素分析、FT-IR、XRD、SEM和TG对其结构进行表征, 并分析了物料比、超声波功率、反应温度、反应时间和碱浓度对超声波法制备XCTS的影响。结果表明超声波法能明显加快制备黄原酸化壳聚糖的速度, 增加产量, 同时提高产物的硫含量, 其最佳工艺:壳聚糖与二硫化碳的质量体积比为1:2(g/mL), 超声波功率为150W, 超声波作用时间为60min, NaOH的质量分数为15%。     

Production of biodiesel from soapstock using an ion-exchange resin catalyst

The feasibility of biodiesel production from soapstock containing high water content and fatty matters by a solid acid catalyst was investigated. Soapstock was converted to high-acid acid oil (HAAO) by the hydrolysis by KOH and the acidulation by sulfuric acid. The acid value of soapstock-HAAO increased to 199.1 mg KOH/g but a large amount of potassium sulfate was produced. To resolve the formation of potassium sulfate, acid oil was extracted from soapstock and was converted to HAAO by using sodium dodecyl benzene sulfonate (SDBS). The maximum acid value of acid oil-HAAO was 194.2 mg KOH/g when the mass ratio of acid oil, sulfuric acid, and water was 10: 4: 10 at 2% of SDBS. In the esterification of HAAO using Amberylst-15, fatty acid methyl ester (FAME) concentration was 91.7 and 81.3% for soapstock and acid oil, respectively. After the distillation, FAME concentration became 98.1% and 96.7% for soapstock and acid oil. The distillation process decreased the total glycerin and the acid value of FAME produced a little.     

Novel biodiesel production technology from soybean soapstock

This paper describes an attractive method to make biodiesel from soybean soapstock (SS). A novel recovery technology of acid oil (AO) from SS has been developed with only sulfuric acid solution under the ambient temperature (25±2 °C). After drying, AO contained 50.0% FFA, 15.5% TAG, 6.9% DAG, 3.1% MAG, 0.8% water and other inert materials. The recovery yield of AO was about 97% (w/w) based on the total fatty acids of the SS. The acid oil could be directly converted into biodiesel at 95 °C in a pressurized reactor within 5 hours. Optimal esterification conditions were determined to be a weight ratio of 1 : 1.5 : 0.1 of AO/methanol/sulfuric acid. Higher reaction temperature helps to shorten the reaction time and requires less catalyst and methanol. Ester content of the biodiesel derived from AO through one-step acid catalyzed reaction is around 92%. After distillation, the purity of the biodiesel produced from AO is 97.6% which meets the Biodiesel Specification of Korea. The yield of purified biodiesel was 94% (w/w) based on the total fatty acids of the soapstock.     

Soybean soapstock utilization: Fatty acid adducts with ethylene and 1-butene

The relation of certain reaction variables to yield was investigated in the preparation of ethylene and 1-butene Diels-Alder adducts with alkali conjugated linoleic and linolenic acid soaps derived from soybean oil soapstock. Adduct yields generally increased with pressure at the 295 C reaction temperature. Maximum yields obtained with fatty acids derived from soapstock were ca. 80% of theory with ethylene and 40% of theory with 1-butene. Purification of adduct methyl esters by vacuum fractional distillation gave adducts with >95% purity. Ethylene adduct amides showed promise as antiblock agents for plastic film.     

Simple, high-efficiency synthesis of fatty acid methyl esters from soapstock

We report a simple method that efficiently esterifies the fatty acids in soapstock, an inexpensive, lipid-rich by-product of edible oil production. The process involves (i) alkaline hydrolysis of all lipid-linked fatty acid ester bonds and (ii) acid-catalyzed esterification of the resulting fatty acid sodium salts. Step (i) completely saponified all glycerides and phosphoglycerides in the soapstock. Following water removal, the resulting free fatty acid sodium salts were rapidly and quantitatively converted to fatty acid methyl esters (FAME) by incubation with methanol and sulfuric acid at 35°C and ambient pressure. Minimum molar reactant ratios for full esterification were fatty acids/methanol/sulfuric acid of 1∶30∶5. The esterification reaction was substantially complete within 10 min and was not inhibited by residual water contents up to ca. 10% in the saponified soapstock. The product FAME contained >99% fatty acid esters, 0% triglycerides, <0.05% diglycerides, <0.1% monoglycerides, and <0.8% free fatty acids. Free fatty acid levels were further reduced by washing with dilute sodium hydroxide. Free and total glycerol were <0.01 and <0.015%, respectively. The water content was <0.04%. These values meet the current specifications for biodiesel, a renewable substitute for petroleum-derived diesel fuel. The identities and proportions of fatty acid esters in the FAME reflected the fatty acid content of soybean lipids. Solids formed during the reaction contained 69.1% ash and 0.8% protein. Their sodium content indicated that sodium sulfate was the prime inorganic component. Carbohydrate was the predominant organic constituent of the solid.     

Fourier Transform Near Infrared Spectroscopy as a Quality Control Tool for the Analysis of Lecithin and By-Products During Soybean Oil Processing

Fourier transform near infrared (FT-NIR) spectroscopy was used to analyze multiple measurement parameters in lecithin production samples and soybean oil refining by-products. For lecithin, partial least squares (PLS) calibration models were developed for acetone insolubles, acid value and moisture and leave-one-out cross validation of the calibration models yielded root mean square error of cross validation (RMSECV) values of 0.37%, 0.59 (mg KOH/g) and 0.050%, respectively. An independent test set consisting of 40% of the lecithin production samples were predicted from the PLS calibration models and a root mean square error of prediction (RMSEP) of 0.41%, 0.53 (mg KOH/g) and 0.056% were obtained for acetone insolubles, acid value and moisture, respectively. Comparison of FT-NIR predictions and corresponding reference method values of 10 lecithin samples using a two-tailed t test showed no significant difference at the p = 0.05 level. A set of 51 samples of soybean oil refining by-products, including acidulated soapstock, fatty acids and black oil, were used for developing PLS calibration models for measuring acid value, moisture and iodine value and leave-one-out cross validations for each model gave values for RMSECV of 6.59 (mg KOH/g), 0.046% and 0.42 (mg I₂/g), respectively. Overall, the results of this study demonstrate the suitability of FT-NIR spectroscopy for the routine analysis of lecithin production samples and soybean oil refining by-products for quality control purposes.     

Fuel properties of biodiesel produced from the crude fish oil from the soapstock of marine fish

The soapstock of a mixture of marine fish was used as the raw material to produce the biodiesel in this study. The soapstock was collected from discarded fish products. Crude fish oil was squeezed from the soapstock of the fish and refined by a series of processes. The refined fish oil was transesterified to produce biodiesel. The fuel properties of the biodiesel were analyzed. The experimental results showed that oleic acid (C18:1) and palmitic acid (C16:0) were the two major components of the marine fish-oil biodiesel. The biodiesel from the mixed marine fish oil contained a significantly greater amount of polyunsaturated fatty acids than did the biodiesel from waste cooking oil. In addition, the marine fish-oil biodiesel contained as high as 37.07 wt.% saturated fatty acids and 37.3 wt.% long chain fatty acids in the range between C20 and C22. Moreover, the marine fish-oil biodiesel appeared to have a larger acid number, a greater increase in the rate of peroxidization with the increase in the time that it was stored, greater kinematic viscosity, higher heating value, higher cetane index, more carbon residue, and a lower peroxide value, flash point, and distillation temperature than those of waste cooking-oil biodiesel.     

橡籽油的酸催化水解工艺研究

以橡籽油为原料进行常压一次酸催化水解反应。研究了反应温度、反应时间、催化剂用量、油水比和乳化剂用量对水解反应的影响,得出橡籽油水解的最优条件:反应温度为95℃,反应时间为9 h,催化剂浓硫酸用量为10%,油水比为1∶2,乳化剂十二烷基磺酸钠用量为1%,此时橡籽油的水解产物酸值为189.41mg KOH/g,水解率为94.71%。     

Chemical Properties and Fatty Acid Composition of Thunbergia fragrans Roxb. Seed Oil

The physicochemical and fatty acid compositions of seed oil extracted from Thunbergia fragrans were determined. The oil content, free fatty acids, peroxide value, saponification value and iodine value were 21.70 %, 2.25 % (as oleic acid), 9.6 (mequiv. O₂/kg), 191.71 (mg KOH/g) and 127.84 (g/100 g oil) respectively. The fatty acid profiles of the methyl esters showed the presence of 90.16 % unsaturated fatty acids and 9.84 % saturated fatty acids. Palmitoleic acid, which is usually found in marine foods and is unique in seed oils of botanical origin, was the major component (79.24 %). The oil can also be used in industries for the preparation of liquid soaps, shampoos and alkyd resin.     

Chemical Composition and Fatty Acid Profile of Khat (Catha edulis) Seed Oil

The proximate, physicochemical, and fatty acid compositions of seed oil extracted from khat (Catha edulis) were determined. The oil, moisture, crude protein, crude fiber, crude carbohydrate, and ash content in seeds were 35.54, 6.63, 24, 1.01, 30.4 %, and 1.32 g/100 g DW respectively. The free fatty acids, peroxide value, saponification value, and iodine value were 2.98 %, 12.65 meq O₂/kg, 190.60 mg KOH/g, and 145 g/100 g oil, respectively. Linolenic acid (C_18:3, 50.80 %) and oleic (C_18:1, 16.96 %) along with palmitic acid (C_16:0, 14.60 %) were the dominant fatty acids. The seed oil of khat can be used in industry for the preparation of liquid soaps and shampoos. Furthermore, high levels of unsaturated fatty acids make it an important source of nutrition especially as an animal product substitute for omega‐3 fatty acids owing to the high content of linolenic acid.     

Effect of ultrasonic assisted KOH pretreatment on physiochemical characteristic and anaerobic digestion performance of wheat straw

In this study, ultrasonic field was applied during potassium hydroxide (KOH) pretreatment of wheat straw (WS). Three concentrations of KOH (2%, 4%, and 6%) were tested during pretreatment. The results showed that there was a significant influence of the ultrasonic assisted KOH pretreatment (KOH_Upt) on physiochemical characteristics of WS during pretreatment as well as on digester performance. The pretreatment time was optimized to 36 h for all KOH concentrations. The highest total volatile fatty acid (TVFA) productions (3189 mg·L^-1) from 6% KOH_Upt samples were observed. Similarly, the SEM analysis and FTIR observation revealed that KOH_Upt effectively disrupted the physical morphology of WS and successful breaking of lignin and hemicellulose linkage between carboxyl groups. Moreover, the highest biogasification (555 ml·(g VS_loaded)^-1) and biomethane productions (282 ml·(g VS_loaded)^-1) from 4%KOH_Upt digesters, with 69% of biodegradability, indicated significant availability of organic matter from KOH_Upt. The R² values (0.993-0.998) in Modified Gompertz Model indicated that the model was feasible to predict methane yield for this study. Similarly, the Bo values for 4%KOH_Upt (283.30 ± 2.74 ml·(gVS_loaded)^-1) were also in agreement to the experimental methane yield. These results suggested that ultrasonic addition during KOH pretreatment of WS can effectively increase the organic yield during pretreatment. Moreover, the increase in methane production from 4% KOH_Upt suggested that digester performance can be improved with lower KOH concentrations using this pretreatment.