Production of alkyl ester as biodiesel from fractionated lard and restaurant grease

Methyl or ethyl esters were produced from lard and restaurant grease by lipase- or base-catalyzed reactions. Before esterifying, some renewable substrates (lard and restaurant grease) should be manipulated through acetone fractionation or on a chromatography column packed with an adsorbent to obtain maximal reaction rate. Because lipase activity was hindered by excess amounts (more than 1 mol) of methanol, each 1 M methanol was added sequentially after 24 h of reaction. Through a three-step reaction, 74% conversion to tallow-methyl ester was obtained. However, a porous substance, such as silica gel, improved the conversion when more than 1 M methanol was used as reaction substrate. When a 1∶3 (fractionated lard/methanol, mole ratio) substrate was used, the conversion rates (i.e., extent of conversion) were 2.7 (24 h) and 2.8% (48 h). However, with 10% silica gel in the reaction mixture, the conversion rates increased to 25 and 58%, respectively. Regenerated restaurant grease (FFA removed through column chromatography) was further converted to esters by alkali-catalyzed methanolysis. After 24 h of reaction, 96% conversion was obtained, while only 25% conversion was observed from crude grease. Alkyl esters produced in this study could be used for fuels, potentially as biodiesel.     

反应温度对猪油环氧化的影响

猪油在甲酸催化下 ,按H2 O2 /C =C摩尔比为 1 5∶1用双氧水进行原位环氧化。通过考察温度对产物碘值和环氧指数的影响 ,发现随温度的升高 ,产物碘值逐渐减小 ;环氧指数先增大后减小 ,6 3℃时达到最大值。猪油分子中参与碘值测定和参与环氧化反应的碳碳双键不完全一致     

A new short-path distillation system applied to the reduction of cholesterol in butter and lard

A molecular distillation plant, built particularly to increase the separation efficiency and to obtain safer working conditions, was tested to remove cholesterol from anhydrous butter and lard. A preliminary experiment was carried out with butter to evaluate the fractionation obtained at temperatures between 190 and 250°C and residual pressures between 10⁻³ and 10⁻⁴ torr. A second experiment was carried out at 185°C and at the maximum operational vacuum, evaluating the fractionation achieved within a time scale between 30 and 180 min. Cholesterol was almost completely removed during the second hour with minimal loss of low-molecular weight triglycerides. An experiment was carried out with lard at 250°C and maximum achievable operational vacuum (10⁻⁴ Torr), lasting approximately 6 h, and cholesterol was removed almost completely during the second hour without significant modifications in the triglyceride composition. This situation remained constant throughout the duration of the test.     

Thermal fractionation and effect of comonomer distribution on the crystal structure of ethylene-propylene copolymers

In this paper the comonomer distributions of two series of ethylene-propylene copolymers with different propylene contents, which were prepared by a fluorinated bis(phenoxyimine) Ti catalyst (FI-EP copolymers) and a conventional Ziegler-Natta catalyst (ZN-EP copolymers), respectively, were characterized. It is found that the comonomer distribution of ethylene-propylene copolymers can still be characterized by thermal fractionation at a long scale, though the propylene units can be incorporated into the PE crystal lattice. The FI-EP copolymers exhibit a narrow and random comonomer distribution, whereas a broad comonomer distribution is observed for the ZN-EP copolymers. The crystal structures of the FI-EP and ZN-EP copolymers were studied by WAXD. The a-axis of the PE crystals of the FI-EP copolymers increases rapidly with propylene content, indicating that more propylene units are incorporated into the PE crystal lattice, whereas only a slight expansion in a-axis is observed for the ZN-EP copolymers. WAXD result also shows the presence of hexagonal phase in the FI-EP copolymers and the relative content of the hexagonal phase increases with the propylene content, while in the ZN-EP copolymers the hexagonal phase is negligible.     

Crystalline fractionation of hydrogenated sunflowerseed oil

Crystalline fractionation of hydrogenated sunflowerseed oil was performed and the chemical composition of the separated fractions at different temperatures was determined. The results show that the triglycerides obtained after a short retention time (less than 16.4 min) were enriched in the low-temperature fractions (lower than 22°C), the triglycerides of long retention time (more than 21.5 min) were concentrated in the higher-temperature fractions (higher than 30°C), and the triglycerides of medium retention time (between 16.4 and 21.5 min) were concentrated in the medium-temperature fractions (22°C to 30°C). The partition ratio of triglycerides with retention times of 8.8, 12.5, 16.5, 21.5 and 29.1 minutes was increased as a function of the fractionation temperature.     

硫化银比浊法测定液氨中微量硫

液氨样品经自然蒸发后,加甲醇蒸馏除去残液中溶解的氨,用硫化银比浊法测定微量硫。该方法准确度较高,取得了满意的效果。     

Detection of lard and randomized lard as adulterants in refined-bleached-deodorized palm oil by differential scanning calorimetry

A study was conducted to assess the use of differential scanning calorimetry (DSC) for detecting the presence of lard/randomized lard as adulterants in refined-bleached-deodorized (RBD) palm oil. Lard extracted from the adipose tissues of pig was chemically interesterified using sodium methoxide as catalyst. DSC thermal profiles of both genuine lard and randomized lard were compared with those of other common animal fats such as beef tallow, mutton tallow, and chicken fat. Lard and randomized lard were then blended with RBD palm oil in two series, in proportions ranging from 0.2 to 20%, and DSC analyses were obtained. The DSC cooling profiles of adulterated RBD palm oil samples showed an adulteration peak corresponding to lard/randomized lard in the low-temperature region. This peak was confirmed as an indicator of the presence of lard in RBD palm oil since similar experiments carried out using other common animal fats such as mutton tallow, beef tallow, and chicken fat showed that the lard adulteration peak could be distinctly identified. Using this method, a detection limit of 1% lard/randomized lard was reached (P<0.0001).     

比浊法测定微量汞的研究

在pH＝4.0的乙酸-乙酸钠缓冲溶液中,N,N-二乙基二硫代氨基甲酸钠和Hg（Ⅱ）反应生成白色沉淀物,用分光光度计于波长400nm处测量其吸光度。溶液中Hg（Ⅱ）浓度在0～14μg·mL^-1范围内与吸光度呈良好的线性关系,相关系数0.9995。用此法测定汞溴红药水中汞含量,相对标准偏差0.23%（n=3）,回收率平均值为92.8%。     

浊度法测定亚麻纤维中微量木质素含量

提出了一种新的木质素定量分析方法,即用浊度法快速测定亚麻纤维中所含微量木质素。用72％硫酸溶液消化亚麻纤维,超声振荡下将难溶的木质素悬浮于甘油水溶液中得到均匀的悬浊液,在660mm波长下测定浊度,用标准曲线法得出其木质素含量。此法的特点是简便、快捷、准确度高,特别适合于微量木质素的测定。     

比浊法测定葵二酸中微量氯离子

建立氯化银比浊法测定有机样品葵二酸中微量氯离子含量的方法并对方法进行了优化。该方法具有很好的重现性和线性关系,在0.1～5 mg.L-1浓度范围内,相关系数均达到0.997以上,加标回收率为97.2%～102.5%,相对标准偏差小于1.5%。该方法简便,快速。     

分光光度比浊法测定工业氢氧化钠中的氯化钠含量

以硝酸银作沉淀剂,丙三醇为氯化银沉淀稳定剂,用分光光度比浊法测定工业氢氧化钠中的氯化钠含量。     

An integrated process of catalytic hydrolysis and membrane separation for fatty acids production from lard oil

An integrated process of catalytic hydrolysis and membrane separation was developed for fatty acids (FAs) production from lard oil. Both sulphonated cation exchange resin (SCER) and 0.98 g/g H₂SO₄ as catalysts were used to produce fatty acids (FAs) from lard oil by three‐step hydrolysis, respectively. Simultaneously, polyethersulphone (PES) ultrafiltration membrane was employed to separate glycerol and water from the products. The hydrophilicity and morphology of the pristine and used PES membranes were characterized by contact angle measurement and field‐emission scanning electronic microscopy, respectively. The final optimal yields of FAs obtained by SCER and H₂SO₄ catalysis at 100 °C and atmospheric pressure were 85.6 % at 16.0 h of operation and 94.5 % at 18.0 h of operation, respectively. Furthermore, the yield of FAs obtained from an integrated process of SCER‐catalyzed hydrolysis and membrane separation achieved up to 99.9 % at 10.0 h, 90 °C, and operating pressure of 100 kPa.

     

Study of the fine crystalline structure of polyethylenes via annealing and thermal fractionation

The fine crystalline structures of two polyethylenes have been investigated with annealing and fractionation techniques via modulated differential scanning calorimetry. The molecular structure and polydispersity of both high‐density polyethylene and low‐density polyethylene have been characterized by multiple‐step annealing and successive self‐nucleation/annealing thermal fractionation methods. The effects of annealing on the crystallinity and mechanical properties and the possible mechanism of the formation of the different fine crystalline structures related to the macromolecular chain motion for the two polyethylenes have also been studied and analyzed according to detailed annealing and fractionation processes. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2686–2691, 2003     

猪板油直接萃取制备生物柴油的研究

研究了猪油原位萃取-酶法转化制生物柴油。考察了溶剂用量、萃取时间、萃取温度等对油脂得率的影响,探讨了以Novozyme 435酶为催化剂直接转化猪油生物柴油。结果表明,萃取猪油的较优参数为:乙酸甲酯为萃取剂,乙酸甲酯用量(mL)与猪板油质量(g)比为8∶1,萃取时间3 h,萃取温度50℃;以Novozyme 435脂肪酶转化猪油制备生物柴油,得率为95.12%,当Novozyme 435酶和Lipozyme TLIM酶混合比为1∶1时,生物柴油转化率最高,达97.12%。     

Effect of molecular weight and average comonomer content on the crystallization analysis fractionation (Crystaf) of ethylene α-olefin copolymers

The effect of molecular weight and average comonomer content on the crystallization analysis fractionation (Crystaf) of ethylene/1-hexene copolymers was investigated experimentally and modeled via stochastic simulations. Molecular weight and comonomer content are the main structural parameters that affect the crystallizability of polymer molecules from dilute solutions. Sets of samples with varying molecular weight and comonomer content were prepared to study each effect separately. Although both structural parameters significantly affect the shape of Crystaf profiles, comonomer content is the main determining factor for Crystaf peak location for most molecular weights of interest. The results of the stochastic simulations show good qualitative agreement with the experimental data, but also indicate some clear limitations that might be related to the kinetics of crystallization effects during Crystaf analysis.     

Solvent fractionation of petroleum pitch for mesophase formation

Petroleum pitch (Ashland A240) has been subjected to thermal treatment and solvent fractionation to produce refined pitches to be evaluated as impregnants for C-C composites. The solvent fractions were obtained by sequential Soxhlet extraction with solvents such as hexane, benzene, and pyridine. Thermal treatment to 408 °C produced a mesophase pitch (≈50% mesophase); an appreciable portion of the mesophase was soluble in strong solvents. There were substantial differences in chemical composition and in pyrolysis behaviour of the fractions. As the depth of fraction increased, the pyrolysis yield and bloating increased, and the microstructure of the coke became finer until glassy microconstituents were formed in the deepest fractions.     

Optimization and kinetic modeling of waste lard methanolysis in a continuous reciprocating plate reactor

Continuous biodiesel production from a waste pig-roasting lard, methanol and KOH was carried out in a reciprocating plate reactor (RPR) using a factorial design containing three process factors, namely methanol/lard molar ratio, catalyst loading, and normalized height of the reactor. The main goals were to optimize the influential process factors with respect to biodiesel purity using the response surface methodology and to model the kinetics of the transesterification reaction in order to describe the change of triacylglycerols (TAG) and fatty acid methyl esters (FAME) concentrations along the RPR height. The first-order rate law was proved for both the reaction and the mass transfer. The model of the changing reaction mechanism and mass transfer of TAG was also applicable. Both kinetic models agreed with the experimental concentrations of TAG and FAME determined along the RPR height.     

Comparison of four accelerated stability methods for lard and tallow with and without antioxidants

The oxidative stability of lard and tallow with and without antioxidants was evaluated by four accelerated stability methods, the active oxygen method (AOM), the oxygen bomb test, the Rancimat method, and the Schaal oven test. The results indicated that the oxidative stability of animal fats and the relative effectiveness of an antioxidant in the fats could have different mechanisms. When the protective index was used to demonstrate the relative effectiveness of the antioxidants, the results suggested that the Rancimat Method may be the least reliable method compared with AOM, oxygen bomb test, and Schaal oven test. More than one accelerated stability method is recommended for evaluating the effectiveness of an antioxidant or the oxidative stability of fats.     

Performance of crystallization analysis fractionation and preparative fractionation on the characterization of γ‐irradiated low‐density polyethylene

The effects of γ‐radiation on a low‐density polyethylene (LDPE) were investigated by novel techniques, such as crystallization analysis fractionation and preparative fractionation, to analyze and compare their performance with other analytical procedures such as DSC, FTIR, and GPC. The LDPE was thus irradiated with four different doses of γ‐radiation. Different fractions were obtained from these irradiated materials by preparative fractionation, which were characterized by the above‐mentioned analysis techniques. The changes in the morphology and chemical structure of LDPE after the irradiation were analyzed and it was found that both oxidative scission and crosslinking are phenomena related to the exposure of LDPE at high‐energy radiation. Crystallization analysis fractionation and preparative fractionation proved to be suitable techniques to characterize the effects of γ‐radiation on a low‐density polyethylene material. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1803–1814, 2004     

Characteristics of bread and buns made with lard and vegetable oils of different iodine values

A good-quality white loaf of bread or rolls can be baked by substituting liquid vegetable oil (canola, soya and palm) for the standard shortening,i.e. lard, tallow or partially hydrogenated vegetable shortening. Canola oil and soya oil produced lower specific volumes of 5.56 and 5.55 cm³/g and higher softness indices when used with mono- and diglycerides only. Palm oil and lard produced specific volumes of 6.33 and 6.15 cm³/g and lower softness indices with mono- and diglycerides. When a blend of surfactants consisting of mono- and diglycerides and sodium stearyl lactylate (SSL) was used at 0.5% of flour weight, palm, canola, lard and soya gave comparable results in specific volume and compressibility. Rolls baked with the same fats and oils, and addition of ethoxylated stearic acid (MYRJ 45H) or a blend of MYRJ 45H and SSL, all gave good specific volumes ranging from 6.92 to 7.27 cm³/g and a softness index range of 0.71–0.86 and 0.68–0.86 after 48 and 96 h of storage. When a proper surfactant is used, good-quality bread and rolls can be baked with liquid vegetable oil. Furthermore, the usage level of liquid oil can be cut by approximately 30% in comparison to lard or shortening while still maintaining quality.