Oxidation of glycerol with H_2O_2 on Pb-promoted Pd/γ-Al_2O_3 catalysts

A series of bimetallic Pd-Pb catalysts with a constant Pd content of 1 wt%and Pb/Pd atomic ratio from 0 to 1.6 supported on γ-Al2O3 were prepared and used for glycerol oxidation with H2O2 as the oxidizing agent at atmospheric pressure,45℃ and pH =11.The morphology and dispersion of the catalysts were characterized by scanning electron microscopy-energy dispersive X-ray spectroscopy（SEM-EDX） and transmission electron microscopy（TEM）.The presence of an alloy phase in the bimetallic catalyst was detected by X-ray photoelectron spectroscopy（XPS）.Glycerol conversion obtained with the monometallic Pd catalyst was 19%,which was increased to 100%with the addition of Pb.The four bimetallic PdPb catalysts were able to oxidize glycerol to dihydroxyacetone（DIHA） and the selectivity to DIHA reached 59%,58%,34%and 25%for PdPb0.25,PdPb0.50,PdPb1.00 and PdPbl.60 catalysts,respectively.

Changes of Protective Enzymes and Accumulation of Polyamines Induced by Boron Deficiency in Roots of Rape Seedlings

The effects of boron deficiency on the membrane permeability, the lipid peroxidation of membrane, the activities of the protective enzymes and the accumulation of polyamines in the roots of rape ( Brassica napus L. cv Zhongyou 821) plants were examined using solution culture experiment. Compared to the 20 mmol B m -3 treatment, boron deficient treatment (2 mmol B m -3 ) decreased root dry weight and increased the rate of solute leakage and malondialdehyde (MDA) concentration in the roots of rape. Similar patterns of change were observed in the level of lipid peroxidation (MDA concentration) and the rate of solute leakage under boron deficiency. Results suggested that a significant alteration of membrane composition had occurred under B deficiency. The concentration of putrescine and the ratio of putrescine to spermidine + spermine in the roots of rape increased significantly, and the activities of superoxide dismutase and catalase decreased in the roots of rape during B deficiency. But peroxidase activity in root of B deficient plant was higher than that of control plant.

Aluminum(Ⅲ) triflate-catalyzed selective oxidation of glycerol to formic acid with hydrogen peroxide

Glycerol is a by-product of biodiesel production and is an important readily available platform chemical.Valorization of glycerol into value-added chemicals has gained immense attention.Herein,we carried out the conversion of glycerol to formic acid and glycolic acid using H2O2 as an oxidant and metal(Ⅲ)triflate-based catalytic systems.Aluminum(Ⅲ)triflate was found to be the most efficient catalyst for the selective oxidation of glycerol to formic acid.A correlation between the catalytic activity of the metal cations and their hydrolysis constants(Kh)and water exchange rate constants was observed.At 70 ℃,a formic acid yield of up to 72% could be attained within 12 h.The catalyst could be recycled at least five times with a high conversion rate,and hence can also be used for the selective oxidation of other biomass platform molecules.Reaction kinetics and 1H NMR studies showed that the oxidation of glycerol(to formic acid)involved glycerol hydrolysis pathways with glyceric acid and glycolic acid as the main intermediate products.Both the [Al(OH)x]^n+ Lewis acid species and CF3SO3H Brosted acid,which were generated by the in-situ hydrolysis of Al(OTf)3,were responsible for glycerol conversion.The easy availability,high efficiency,and good recyclability of Al(OTf)3 render it suitable for the selective oxidation of glycerol to high value-added products.

Comparative Study on Oxidative Desulfurization of FCC Gasoline by Ce^(4+) Compound and H_2O_2

This article describes two kinds of model oil samples made of a benzothiophene/octane mixture and a 2-me- thylthiophene/octane mixture. Furthermore, this paper investigates the oxidative desulfurization selectivity and reaction efficiency when Ce4+ compound and H2O2 having identical electron equivalent weight were used as oxidants. The test re- sults showed that the two kinds of oxidants were more effective to remove benzothiophene in the model oil samples. For oxidative desulfurization of 2-methylthiophene, Ce4+ compound was obviously superior than H2O2. This paper by means of quantum chemistry analyses elaborates the complex formed between Ce4+ species and 2-methylthiophene and FT-IR spec- trograms of model oil samples before and after oxidation by Ce4+ compound and H2O2, respectively. The results demonstrat- ed that Ce4+ compound could remove sulfur compounds not only through oxidation reaction but also through complexation reaction.

THE EFFECTS OF S-3-1 ON LIPID PEROXIDATION AND SCAVENGING FREE RADICALS INVITRO

S 3 1 is a simplified synthetic analogue of the active principle of Salvia miltiorrhioza. Electron spin resonance spectrometry using 5,5′ dimethyl 1 pyrroline N oxide as a scavenger of free radicals indicated that 200 μg/ml of S 3 1 scavenged 1,1 diphenyl 2 picrylhydrazyl radicals completely. 25μg/ml of this compound quenched 100% of superoxide anion and a concentration of 250 μg/ml of S 3 1 quenched 63% of hydroxyl radicals. It was also shown that 3 56 mg/ml of S 3 1 could inhibit lipid peroxidation in microsome fraction from rat liver induced by FeSO 4 and cysteine. These results show that S 3 1 is an effective antioxidant by scavenging free radicals.

Green and efficient epoxidation of methyl oleate over hierarchical TS-1

The epoxidation of methyl oleate(MO)was conducted in the presence of aqueous H2O2 as the oxidant and hierarchical TS-1(HTS-1)as the catalyst;the catalyst was synthesized using polyquaternium-6 as the mesopore template.The effects of various parameters,i.e.,H2O2/C=C molar ratio,oxidant concentration,amount of the catalyst,reaction temperature,and time,were systematically studied.Furthermore,response surface methodology(RSM)was used to optimize the conditions to maximize the yield of epoxy MO and to evaluate the significance and interplay of the factors affecting the epoxy MO production.The H2O2/C=C molar ratio and catalyst amount were the determining factors for MO epoxidation,wherein the maximum yield of epoxy MO reached 94.9%over HTS-1 under the optimal conditions.

Moro orange juice prevents fatty liver in mice

AIM:To establish if the juice of Moro,an anthocyaninrich orange,may improve liver damage in mice with diet-induced obesity.METHODS:Eight-week-old mice were fed a high-fat diet(HFD) and were administrated water or Moro juice for 12 wk.Liver morphology,gene expression of lipid transcription factors,and metabolic enzymes were assessed.RESULTS:Mice fed HFD displayed increased body weight,insulin resistance and dyslipidemia.Moro juice administration limited body weight gain,enhanced insulin sensitivity,and decreased serum triglycerides and total cholesterol.Mice fed HFD showed liver steatosis associated with ballooning.Dietary Moro juice markedly improved liver steatosis by inducing the expression of peroxisome proliferator-activated receptor-α and its target gene acylCoA-oxidase,a key enzyme of lipid oxidation.Consistently,Moro juice consumption suppressed the expression of liver X receptor-α and its target gene fatty acid synthase,and restored liver glycerol-3-phosphate acyltransferase 1 activity.CONCLUSION:Moro juice counteracts liver steatogenesis in mice with diet-induced obesity and thus may represent a promising dietary option for the prevention of fatty liver.

An Investigation to Assess Storage Stability of Pomelo Seed Oil Biodiesel

Biodiesel is a biomass-based renewable and clean fuel. It can be used directly in existing diesel engines without any modification. In spite of having so many advantages, it has an issue regarding long-term storage stability. Biodiesel oxidizes when it comes in proximity of light, temperature, humidity, metals etc. The oxidation causes precipitation and sedimentation in the fuel. Such biodiesel is unfit to use in engines. Hence, this study aims to assess the storage stability of pomelo seed oil （Citrus maxima） biodiesel over a period of five months upon storage both in open and closed condition. Storage stability of biodiesel is determined in terms of acid value, peroxide value and viscosity at regular interval of time. It is observed that there is a strong relationship between oxidation and outside factors such as light, temperature fluctuations and humidity level. Upon exposure to these factors, oxidation in biodiesel accelerated greatly.

Oxidation Stability of Camellia Oil During Refining

In this paper, the crude camellia oil extracted by cold pressing and deacidified oil, decolorized oil, dewaxed oil and finished tea oil obtained in different refining stages were studied. The changes of acid value, peroxide value and free radical scavenging ability of camellia oil in each stage were compared and analyzed.The results showed that the total phenol content of crude oil was the highest, and the total phenol content of alkali refined crude oil decreased significantly. After dewaxing, the total phenol concentration of camellia oil increased by 63.5%. The reason may be that low temperature conditions contributed to the recovery of phenolic structure in camellia oil, and without the influence of alkaline solution, the damage degree of phenolic substances was greatly reduced, thus elevating the total phenol content. The lowest peroxide value of camellia oil was observed in the alkali-refining deacidification stage, which decreased by 29.3%. Crude oil had the highest acid value and concentration of antioxidant substances. After alkali-refining deacidification,the acid value and the concentration of antioxidant substances dropped by 85.3%and 88.9%, respectively. Total phenols had the strongest correlation with acid value,followed by free radical scavenging ability, and the correlation with peroxide value was not obvious.

Studies on Various Physico-Chemical Characteristics of Some Vegetable Oils

The industrial chemistry of oils and fats is a mature technology, with decades of experience and refinement behind current practices, therefore some physico-chemical characteristics of eleven vegetable oils sunflower oil （four different manufacturing companies）, olive oil （three different manufacturing companies）, corn oil, castor oil, coconut oil and canola oil in Iraqi Kurdistan region （Hawler city center） have been evaluated according to association of official analytical chemists （AOAC） （1995） official methods. The refractive index, viscosity, acid value, peroxide value, pH values, and values of specific gravity of the vegetable oil samples were measured at various different conditions. The results showed that some of the oil samples have unacceptable values in comparison with the standards.

Variation of the Content of Ethyl Esters in Extra Virgin Olive Oils during Their Shelf Life

Fatty acids＇ ethyl and methyl esters are not natural components of edible vegetable oils and therefore should not be present in virgin olive oils. Among the quality requirements for extra virgin olive oils, the International Olive Council （IOC） Norm, 2015 review, set limits for the ethyl ester content at ≤ 435 ppm for the 2014/2015 and 2015/2016 harvests and at ≤ 30 ppm for the 2016/2017 harvest. The purpose of this paper is to： （a） determine the alkyl ester content in two extra virgin olive oils （of the Arbequina and Coratina varieties） as parameters of quality at the moment of their elaboration and to assess the length of their shelf life, over a 12 month period at room temperature; （b） determine extra virgin olive oils＇ free alcohols content as these may esterify due to the free fatty acids present during storage. After 6 months of storage, the Arbequina oil＇s ethyl ester content was 32 ppm, and the Coratina＇s was 46 ppm. As a result, the shelf life for both was only about half a year （labeling usually indicates it must be consumed ＂before 1 year＂）. However, parameters related to oxidation （peroxide index, K 232, K 270 and AK） remained within the limits set by the International Olive Council （IOC） throughout the year. In conclusion： ethyl ester content is a very fine parameter for assessing the quality of extra virgin in an olive oil and determining the length of its shelf life.

Photochemical Method to Evaluate Oxidation Levels in Heat-Treated Vegetable Oil： Comparison with Peroxide-Value and Acid-Value

To determine the degree of oxidation in vegetable oil, a photochemical method using the electron spin resonance （ESR） spin trapping technique was developed, and the results were compared with those obtained using conventional peroxide-value （PV） and acid-value （AV） methods. Vegetable oil heat-treated were subjected to short UV illumination, and the produced alkyl-oxyl radicals were identified and quantified using the ESR spin trapping technique. ESR signal intensity was used as an indicator of oil oxidation, which monotonically increased as a function of the heat-treatment time. Commercially, available oils were selected and analyzed. The results were compared with those obtained using the PV and AV methods. The present method displayed some analogies with the PV method at least in the early stage of heating. Overall, the present method had highly sensitive and capable of detecting early-stage oxidation in vegetable oil.

Effect of Microwave Radiation on Dielectric Behavior of Two Vegetable Oils

The effect of microwave （MW） heating on the dielectric properties and oxidation processes of virgin olive oil and refined sunflower oil were determined by dielectric and UV- spectroscopy. Samples were heated in the microwave oven （850 W, 2.450 MHz） for 0 to 14 minutes. The results show degradation of dielectric characteristics, conductivity and oxidative stability of investigated oils, increasing with the exposure time. UV spectrum shows only one defined peak at 206 nm for olive oil confirming the dominant presence of monounsaturated fats and four peaks for sunflower oil （203 nm, 230 nm, 269 nm and 278 nm） dependent on polyunsaturated acid fats contents. Increasing of absorbance at all peak wave lengths indicates production of lipid oxidation, due to formation of conjugated monoenes and dienes and in small amounts due to trienes and secondary products like ketoaldehydes. Dielectric constant for olive oil is stable and almost unchangeable with MW radiation while sunflower oil＇s c＇ oscillates around the origin value in greater rate. Dielectric loss e＂ decreases with increasing time of MW radiation and its maximum shifts towards higher frequencies for sunflower oil indicating shortening of the relaxation times, while for olive oil it is unchanged. Cole-Cole analysis show the presence of only one relaxation process in the oils. Conductivity of oils is increasing in similar way with increasing frequency following the Jonscher＇s power law and is not changed with MW exposure time. Olive oil has conductivity higher for four orders of magnitude than sunflower oil, which is connected to the high content of monounsaturated fats. The differences between sunflower and olive oil characteristics are discussed.

The Potential Application of Plant Essential Oils/Extracts as Natural Preservatives in Oils during Processing： A Review

The present work summarizes recent investigations carried out about the usage of natural antioxidants in lipid-rich food during processing. Synthetic antioxidants have been used as food additives to retard lipid oxidation and development of off-flavor for over 50 years. However, the literature has expressed safety concerns and health risks （toxic and carcinogenic effects） associated with the use of synthetic antioxidants recently. Natural antioxidative substances from the polyphenols of edible plants are believed to be safer and may provide with additional health benefits and more effective compared to synthetic antioxidants. Due to the fact that natural antioxidants are additives that people mixed with food and consumed for centuries, they are known to be safe by the consumer. Therefore, it is an area worth to investigate due to consumer concerns about health. In the literature, there are many studies showing that the natural antioxidants have important antioxidant effect. Plants （oil seeds, cereals, vegetables, fruits, herb and spices）, compounds from animal source （peptides and amino acids）, enzymes and some microorganisms are important natural antioxidants. Plant extracts have been widely used to retard lipid oxidation in foods during frying and accelerated storage processes. They were found as strong antioxidant sources due to their high contents of phenolic compounds. There are countless studies about natural antioxidants. However, they have not been investigated completely by means of toxicology.

The Application of CO2-EOR in Ultra-Low Permeability Reservoir

CO2 flooding is a process whereby carbon dioxide is injected into an oil reservoir in order to increase output when extracting oil. Since 1952, Wharton obtained the patent concern CO2 flooding, CO2-EOR （CO2 flooding enhance oil recovery） has been one of research hot-spot around the world. According to the statistical data of 2006, there are total of 94 global CO2-EOR projects, including 65 low permeability oilfield projects （79% of the total）. Daqing Oilfield is the largest one of China, after more than 50 years of continuous development, oilfield comprehensive water cut has reached over 90%, and the difficulty of oilfield development has been gradually increasing. In recent years, low and ultra-low permeability reservoirs development have played a more and more important role accompany with low permeability reserves in proportion of the total reserves have been increasing year by year. But water-flooding recovery of low permeability reservoir is very low under the influence of reservoir poor properties and heterogeneity. As a kind of greenhouse gas, CO2 flooding can obtain good results for the low permeability reservoir in which the water flooding has proven ineffective. CO2 flooding Pilot Test was conducted under such background since Dec. 2002, over 10 years of practice has proved that CO2 flooding is an effective method to improve the development effect of low permeability reservoir, all experience during the mechanism study and field test should present important references for further larger-scale CO2 flooding projects.

用于唇部的结痂制剂

一种新制剂含有过氧化天然油(Ⅰ)和α-乙酰扁桃酸(madelic acidⅡ)。过氧化油最好选用甜杏仁油、玉米和芝麻油,制剂以含(Ⅰ)65％～99％,(Ⅱ)1％～35％为最宜。可制成乳剂、膏剂或凝胶或专作成唇膏。局部使用本制剂有结痂作用。