Research progress on classification,source,application of phytosterol esters,and their thermal oxidation stability

Phytosterol esters can effectively decrease serum cholesterol concentration in the human body and prevent cardio-cerebrovascular diseases.It was found that phytosterol esters exhibited better solubility and bioavailability than free phytosterols.In recent years,phytosterol esters have attracted increasing attention.However,during food processing,phytosterol esters are susceptible to degradation at high temperatures,resulting in certain losses and formation of potentially harmful substances for humans.This paper reviews the relevant literatures and updates on the thermal oxidation stability of phytosterol esters in recent years from the following aspects:(i)Sources,physiological activities,and applications of phytosterol esters;(ii)Oxidation mechanism of phytosterol esters;(iii)Effects of phytosterols species,the volume of addition,food matrix,heating temperature and time,and antioxidants on the thermal loss and oxidation stability of phytosterol esters.The research progress on the safety of phytosterol esters is also discussed in detail.Additionally,the prospects for future research are highlighted.

Pollution characteristics and risk assessment of organophosphate esters in aquaculture farms and natural water bodies adjacent to the Huanghe River delta

To date,little attention has been paid to the effects of organophosphate esters(OPEs)pollution on aquacultural environment and aquatic product safety.Huanghe(Yellow)River delta area is one of the largest aquaculture centers in China,where ecological security protection is crucial in the national strategy of China.To explore the pollution characteristics,bioaccumulation,and health risks of OPEs in aquaculture farms in the Huanghe River delta and natural water bodies in the adjacent seas,five species of organisms from different farm types nearby the Huanghe River delta,and the corresponding culture water and sediments were sampled in this study.The total concentrations of Σ_(13)OPEs in water,sediments,and organisms were 51.53-272.18 ng/L,52.63-63.17 ng/g dry weight(dw),and 46.82-108.90 ng/g dw,respectively.Among the five types of culture ponds,the water samples from the swimming crab and hairy crab culture ponds exhibited higher OPEs,the concentration of OPEs in the sediments from the few ponds was relatively balanced,and the OPEs in the organism from the holothurian ponds was higher.Tris(1,3-dichloro-2-isopropyl pho sphate)(TDCP)was the main contaminant in water samples and tripropyl phosphate(TPrP)in sediments and organisms.However,trisphenyl phosphate(TPhP)showed the strongest bioaccumulation ability,followed by 2-ethylhexyl diphenyl phosphate(EHDPP)and TPrP.The bioaccumulation capacities of the five species were as follows:prawn>holothurian>hairy crab>swimming crab>carp.These five types of organisms,as main seafood in human consumption,were at low risk of negative impacts of pollution.However,the risk from the mixture of organophosphate flame retardants(OPFRs)still requires more attention due to the increasing consumption and production in the world.

Adsorption of Phthalic Acid Esters by Humic Acid and Its Research Progress

Humic acid is rich in highly electronegative oxygen-containing organic functional groups,so it has high reactivity and can adsorb phthalic acid ester(PAEs)in the environment to reduce the risk of environmental pollution from PAEs.In this paper,the extraction,characterization and adsorption models of humic acid were reviewed,and the research status of adsorption of PAEs by humic acid was further summarized.Based on these,the feasibility and observable application prospect of humic acid as a cheap adsorbent were analyzed.

Insights into biobased epoxidized fatty acid isobutyl esters from biodiesel:Preparation and application as plasticizer

Biodiesel was used to prepare epoxidized fatty acid isobutyl esters(Ep-FABEs)as a biobased plasticizer in this work.Transesterification of biodiesel with isobutanol catalyzed by tetrabutyl titanate was carried out in a gas-liquid tower reactor.The conversion achieved nearly 100%within 5 h under the reaction temperature,the mass ratio of catalyst to fatty acid methyl esters(FAMEs),and isobutanol to FAMEs total molar ratio of 180℃,0.4%(mass),and 5.4:1,respectively.In addition,kinetic model of the transesterification reaction was developed at 150–190℃.The calculated activation energy was 48.93 kJ·mol^(-1).Then,the epoxidation of obtained fatty acid isobutyl esters(FABEs)was conducted in the presence of formic acid and hydrogen peroxide.The Ep-FABEs was further analyzed for its plasticizing effectiveness to replace dioctyl phthalate(DOP)and compared with conventional epoxy plasticizer epoxidized fatty acid methyl esters(Ep-FAMEs).The results indicated that the thermal stability and mechanical properties of PVC films with Ep-FABEs plasticizer were significantly improved compared with those plasticized with DOP.In addition,the extraction resistance and migration stability of Ep-FABEs were better than those of EpFAMEs.Overall,the prepared Ep-FABEs via structural modification of biodiesel proved to be a promising biobased plasticizer.

Novel Phosphonoacetic Acid Derivatives.Synthesis of N-(Ethoxycarbonylmethylphosphonyl)-α-Amino Esters and-α-Amino Phosphonic Acid Esters and Their Bioactivities

A series of novel phosphonoacetic acid derivatives, N-(ethoxycarbonylmethy-ethoxyphosphonyl)-α-amino acid esters and α-amino phosphonates, were synthesized via the reaction of the corresponding phosphonyl chloride with amino acid ester hydrochlorides or amino phosphonates in the presence of a base. The preliminary bioassay shows that some compounds show significant anti-viral activity against tobacco mosaic virus (TMV)

Two new olean-type triterpene fatty esters from Scorzonera mongolica

Two new triterpene fatty esters, 33-tetradecanoyl moradiol 1 and 3β-dodecanoyl moradiol 2, were isolated from Scorzonera mongolica. Their structures were elucidated as 3β-tetradecanoyloxy-28-hydroxylolean-18-ene and 3β-dodecanoyl-28-hydroxyl-olean-18-ene on the basis of IR, MS, ID NMR and extensive 2D NMR spectroscopic analyses.

Boosted Biodegradability and Tribological Properties of Mineral Base Oil by Methyl Diethanolamine Fatty Acid Esters

Methyl diethanolamine fatty acid esters, viz. methyl diethanolamine octanoate and methyl diethanolamine oleate,were prepared. Their impacts on the biodegradability and tribological properties of mineral base oil 400 SN were evaluated by a tester for fast evaluating the biodegradability of lubricants and by a four-ball tester, respectively. The results showed that methyl diethanolamine octanoate and methyl diethanolamine oleate both could markedly promote the biodegradation of the oil and improved its tribological properties. The improvement of biodegradability was attributed to the enhanced growth and quantity of microbes by methyl diethanolamine fatty acid esters. The worn surfaces were analyzed by a scanning electron microscope(SEM) equipped with an energy dispersive spectrometer(EDS) and an X-ray photoelectron spectroscope(XPS). The results indicated that the enhancement of friction-reducing and anti-wear properties of the mineral oil was attributed to the formation of complicated boundary lubrication films composed of species such as Fe_2O_3, Fe_3O_4 and organic nitrogen-containing compounds with a structure of –C-N-or R-NH_2.

12-Deoxyphorbol Esters from Euphorbia Fischeriana

１２－ＤｅｏｘｙｐｈｏｒｂｏｌＥｓｔｅｒｓｆｒｏｍＥｕｐｈｏｒｂｉａＦｉｓｃｈｅｒｉａｎａＷｅｎＺｉＬＩＵ；ＸｉａｏＹｕｎＷＵ；ＧｅｎＪｉｎＹＡＮＧ；ＱｉｎｇＧａｏＭＡ；ＴｉａｎＸｉＺＨＯＵ；ＸｉＣａｎＴＡＮＧａｎｄＧｕｏＷｅｉＱＩＮ（Ｄｅｐａｒｔｍ...

Nickel (Ⅱ) Complex Catalyzed Conjugate Addition Reaction of Functionalized Organozinc Reagents to α,β-Unsaturated Esters

Functionalizedorganozinchandes(FG-ZnX)haveprovedtobeveryusefulinorganicsynthesisinrecentyears'.Theycanalsobesuccessfullyusedinconjugateadditionreactionswithcarbonylcompounds'.However,stoichiometriccoppersaltCuCN'ZLiCImustbeusedinmostcasesl'2andunsatu...

POLAR SUBSTITUENT EFFECTS OF ORGANOPHOSPHORUS ESTERS IN STRUCTURE-REACTIVITY STUDIES

In order to study the polar substituent effect almost with no steric effect in organophosphoruschemistry,a series of 4-substituted-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane 1-oxides（1）and p-substitutedphenylphosphonates（2）and corresponding mono hexyl esters（3）as model were synthesized.31P-NMR chemicalshifts of compounds（1）in methanol and deuterioacetone were determined.The Δδ values reflect 4-sbstituent po-lar effect.The 31P-NMR of compounds（2）and（3）and the pKa of compounds（3）were also measured.Theresults showed that the trend of polar effects of substituents in both carboxylic and organophosphates chemistryare similar,and the change of polar effects in variation with the alkyl groups is not significant.

ENZYME REACTION IN AQUEGUB-ORGANIC BYSTEM —KINETIC RESOLUTION OP RACEMIC OXIRANECARBOXYLIC ESTERS WITH LIPASE

The chiral oxiranecarboxylic acids or esters 2a-e were obtained with lipase (CCL) in aqueous-organic system.The ee and the absolute configurations of the products were determined.

Supercritical Synthesis of Ethyl Esters via Transesterification from Waste Cooking Oil Using a Co-Solvent

Biofuels became more promising alternative to the fossil fuels because of the depletion of fossil resources, renewability, environmental benefits, and energy security. Ethanolysis of waste cooking oil with hexane as co-solvent was carried out for the production of fatty acid ethyl ester (FAEE). This process reduced the severity of process parameters with high purity biodiesel yield. Process variables such as co-solvent ratio, ethanol to oil molar ratio, reaction temperature and reaction time were optimized. The maximum biodiesel yield of 88% was obtained at ethanol/oil molar ratio of 40:1, co-solvent (hexane) to oil ratio of 0.2% (v/v), reaction temperature of 300°C in 20 min of reaction time. Fatty acid ethyl ester (biodiesel) samples produced from this process were measured and evaluated using GC-MS analytical instrument. Thermo gravimetric analysis (TGA) was also performed to examine the thermal stability of waste cooking oil, ethyl esters and fuel blends. Fuel properties of ethyl esters were determined and compared with the ASTM standards for biodiesel, regular diesel and ethyl esters from different feedstock.

Enzymatic synthesis, antioxidant ability and oil-water distribution coefficient of troxerutin fatty acid esters

Troxerutin fatty acid esters were prepared using troxerutin and fatty acid vinyl esters as substrates in pyridine through enzymatic route. The structures of as-prepared compounds were identified by FT-TR, NMR, and ESI-HRMS. Using alkaline protease(≥30 mg/mL) as enzyme, maximum yields reached 58% at 3:1(vinyl hexanoate to troxerutin) in pyridine(water content ≤1%). The yields gradually declined as chain length of acyl donors rose. The antioxidation abilities of the as-obtained compounds were confirmed by both DPPH free radical scavenging and potassium ferricyanide reduction methods. The antioxidation ability of troxerutin fatty acid esters was found lower than that of troxerutin. However, the logP values of troxerutin fatty acid esters varied from 0.15 to 1.94, suggesting that troxerutin fatty acid esters had better lipophilicity than troxerutin(logP =-2.12) when compared to their oil-water distribution coefficients. Overall, these findings look promising as reference for further development of future troxerutin.

Occurrence and distribution of phthalate esters (PAEs) in wetland sediments

This study investigated the occurrence and distribution of 15 phthalate esters(PAEs) in sediments collected from Qixinghe wetlands, northeast China. Total concentration of PAEs in all sediments ranged from 128.41 to 502.79 μg kg^(-1), with the mean value of 284.61 μg kg^(-1).PAEs significantly differed among wetland types; the average PAEs concentration of surface sediments were as follows: Phragmites australis wetland(PAW, 419.87 ±73.61 μg kg^(-1)) [ Carex lasiocarpa wetland(CLW,304.18 ± 56.47 μg kg^(-1)) [ Deyeuxia angustifolia wetland(DAW, 129.78 ± 18.24 μg kg^(-1)). Dimethyl phthalate(DMP), diisobutyl phthalate, di-n-butyl phthalate, and di-(2-ethylhexyl) phthalate(DEHP) were found in all sediments,DEHP was the most abundant PAEs congeners with concentrations varying from 37.62 to 294.9 μg kg^(-1). DMP and DEHP exhibited relatively higher concentrations in CLW and PAW wetlands than in DAW, indicating that the different deoxidization and biodegradation conditions could have important implications for the distribution patterns of PAEs in wetland sediments. The variation of PAEs concentrations in horizontal and vertical sediments with wetland types could be attributed to the migration of contaminants by surface water, groundwater and atmospheric deposition. The occurrence and distribution of PAEs in wetlands also sμggests that contamination in natural ecosystems should not be overlooked.

Michael Additions of Activated Methylene Compounds to α,β-Unsaturated Esters Promoted by Samarium (Ⅲ) Iodide

Promoted by SmI3 β -diketones， β-ketoesters and α -cyano esters were added to α,β -unsaturated esters to form δ-carbonyl esters in mild conditions in moderate to good yields.

Addition of Organosamarium Reagents toα, β-Unsaturated Esters

Allylsamarium bromide reacts with Q, 6 -unsaturated esters and a -alkyloxy carbonyl α, β-unsaturated esters to give l,2-addition and 1 .4-addition products respectively.

A NEW ONE-STEP REDUCTIVE N-ALKYLATION OF AMINO ACIDS AND THEIR ESTERS

The reductive alkylation of amine with carbonyl compounds usingsodium hydrogen telluride has been investigated in recent years.Application of this method to the synthesis of N-alkyl derivativesof biologically important amino acids and their esters is described.

THE REACTION OF p－NITROPHENYLSULFONYLACETONITRILE WITH α，β－UNSATURATED ESTERS AND NITRILES

ＴＨＥＲＥＡＣＴＩＯＮＯＦｐ－ＮＩＴＲＯＰＨＥＮＹＬＳＵＬＦＯＮＹＬＡＣＥＴＯＮＩＴＲＩＬＥＷＩＴＨα，β－ＵＮＳＡＴＵＲＡＴＥＤＥＳＴＥＲＳＡＮＤＮＩＴＲＩＬＥＳ￥ＧｕｏＲｅｎＹＵＥａｎｄＺｈｅｎｇＺｈａｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｓｔ...

LOW-VALENT TITANIUM INDUCED REDUCTIVE CROSS-COUPLING REACTION OF ESTERS WITH DIARYL KETONES

The intermotecular coupling reaction of esters with diarvl ketones induced by titanium tetrachtoride and zinc powder was studied.

ADDITIVE EFFECT ON THE MI CELLE－CATAL TIC HYDROLYSIS OF CARBOXYLIC ACID ESTERS

ＡＤＤＩＴＩＶＥＥＦＦＥＣＴＯＮＴＨＥＭＩＣＥＬＬＥ－ＣＡＴＡＬＴＩＣＨＹＤＲＯＬＹＳＩＳＯＦＣＡＲＢＯＸＹＬＩＣＡＣＩＤＥＳＴＥＲＳｋＷａｎｄｈｏ：ｒａｔｅｃｏｎｓｔａｎｔｓｆｏｒｓｏｌｕｔｉｏｎｓｆｉｔｈａｎｄｆｉｔｈｏｕｔＣＴＡＢ（０．００４３８ｍｏｌｄｉｎ－．）．ＦＩｇ．Ｉｋｅｇｖｓ．ＣＯＴ￣ｎｆｏｒＮＰＰｉｎＦｉｇ．２ＥｆｆｅｃｔｏｆＮＨ３－ｂｕｆｆｅｒｕｐｏｎＮａＺＣＯ．－ＮａＨＣＯ３ｂｕｆｆｅｒｓｏｌｕｔｉｏｎｔｈｅｈｙｄｒｏｌｙｓｉｓｒａｔｅＯｆＮＰＰＴＩｐａｑｕｅｏｕｓｓｎｉｎｔｉｎｎｏｆ０．００４３８ｍｏ１ｄｉｎ－－３ＣＴＡＢｗａｓｕｓｅｄａｓｔｈｅｍｌｃｅｌＩａｒｓｏＩｌ］ｔＩｏｎｂｅｃａｕｓｅｉｔｉｓｔｈｅｓｉｔＩｕｔｉ（ＩｎｏｆｏｐｔｉｍｕｍｃａｔａｌｙｉＩｃｅｆｆｅｃｔｉｎｔｈｅＮａＺＣＯｇ－ＮａＨＣＯ３ｂｕｆｆｅｒ，ａｓｓｈｏｗｎｉｎＦｉｇ．１．Ｆｏｒｔｈｅｓａｍｅｅｓｔｅｒ．ＮＰＰ，ｋ．１＜ｋ．．ａｎｄＰＨ，ｒｅｐＨＺｗｌｏ，ａｎｄｋｏＺ＝Ｋｏ３ｂｕｔＰＨ：＞ｐｌｌ．．Ｔｈｅｓｅｕｎ－ｒｅａｓｏｎａｂｌｅｒｅｓｕｌｉｓｍａｙｂｅｄｌｌｅｔｏｔｈｅｓｌｍｌＪＩｔａｎｅｏｕｓａｍ?