The nature of active sites in Pt–ReO_X/TiO_2 catalysts for selective hydrogenation of carboxylic acids to alcohols

The highly dispersed Pt-ReOx （x _〈 1 ） sites ca. 0.5 nm in size were formed via a successive and strong inter- action of the Re precursor with titania and then of the Pt complex with deposited low-valent rhenium oxide clusters. The size, charge and chemical composition were characterized by means of HRTEM/STEM with EDX mapping, XPS, and FTIRS. These sites with Re/Pt = 2 were shown to be highly active and selective in the hydrogenation of carboxylic acid to alcohol under very mild conditions （T = 130 ℃, P = 50 bar）. The reaction rate constant for the hydrogenation of hexanoic acid increased linearly with the Pt content. As for the homogeneous pincer-type Ru-organic complexes, the active Pt-ReOx sites can dissociate heterolytically the molecular hydrogen with the formation of hydroxyl groups and Pt hydride for hydrogenation of the carboxylic group. Indeed, TOF of 20 h 1 and selectivity of 98%-99% are approaching the values typical of homogeneous catalysts. The first order kinetics described well the experimental data obtained in a wide range of reaction conditions.

Isolation, Purification, and Identification of a Novel HX-Producing Strain and Optimization of Its Fermentation Medium

Hexanoic acid (HX) is a crucial flavor compound and precursor of ethyl caproate (EA), which determines the quality of Chinese Luzhou-flavor liquor (CLFL). The isolation, purification, identification, and optimization of fermentation conditions of HX-producing bacteria are essential for industrial CLFL production. In this study, one strain of HX-producing bacterium was isolated from six candidate bacterial strains and identified as Clostridium sartagoneforme. Then, the growth characteristics and HX production of C. sartagoneforme were investigated. Sodium acetate medium was identified as the optimal fermentation medium from four candidate media. C. sartagoneforme yielded 800.85 ± 12.87 mg/100mL HX in sodium acetate medium. Then, to further optimize the formula of the fermentation medium, the carbon and nitrogen sources and inorganic salt component of the fermentation medium were investigated using HX yields as an optimization index. Optimization was performed with a single-factor experiment and the Taguchi design method. The single-factor experiment showed that the highest HX outputs were obtained when the sodium acetate medium contained 2.5 g/L yeast extract, 1.8 g/L KCl, 20 g/L sodium acetate, 15 mL/L ethanol, and 1.5 g/L glucose. In the orthogonal experiment designed using the Taguchi design method, HX yields reached 2018.29 ± 46.37 mg/100mL in sodium acetate medium that contained 3.5 g/L yeast extract, 1.8 g/L KCl, 25 g/L sodium acetate, and 15 mL/L ethanol.

Catalytic Esterification of Medium-Chain Fatty Acids:Kinetic Investigations

Medium-chain fatty acids (MCFA) are straight-chain fatty acids with aliphatic tails of 6 - 12 carbons, which can form medium-chain triglycerides. They are found mostly in animal fats and in the tropical vegetable oils. Because of their wide applications in industry, there is a growing demand of esters of medium-chain fatty acids production. The aim of our work was investigations of the kinetics of the synthesis of esters of MCFA in the presence of dowex catalyst in wide range of process parameters. Hexanoic, octanoic and decanoic acids were esterified with n-octyl alcohol in the presence of sulfuric acid and commercial dowex W50X8 as catalysts in an experimental semi-periodic glass tank reactor with instantaneous and complete water removal. Because of complete removal of water from the reacting mixture, thus eliminating the reverse hydrolysis reaction, the esterification can be assumed as irreversible reaction. The temperature range was 393 - 423 K, the range of initial mole ratio of alcohol to acid was 3 - 10. The kinetic parameters are given. The reaction kinetics appeared to be of the first order with respect to the acid. The effect of temperature on the reaction rate follows the Arrhenius equation well.

Synthesis, Resolution, and Enantiomeric Purity Assay of 2-n-Butylbutanedioic Acid 4-t-Butyl Esters

Racemic 2-n-butylbutanedioic acid 4-t-butyl esters were synthesized from methyl hexanoate and t-butyl α-iodoacetate via alkylation and subsequently selective hydrolyzation. The （R）-and （S）-2-n-butylbutanedioic acid 4-t-butyl esters were obtained by the resolution of the above-mentioned racemic compounds with（S）-（ - ） or（R）-（ ＋ ）-α- methylbenzylamine, respectively. The e.e. values of the two optical active products were determined to be above 99% by HPLC after the formation of two pairs of diastereoisomers with（R）-（ ＋ ）-α-methylbenzylamine and（S）- phenylalanine methyl ester.

Study on Promoting Cabbage Growth with Diethy Amioethyl Hexanoate 5% AS

Field efficacy trials showed that Diethy Amioethyl Hexanoate 5% AS could promote growth and increase yield of cabbage. The cabbage yield increase rate was up to 40.37% by using reagent dilution 2 000 -2 500 times twice, so Diethy Diethy Amioethyl Hexanoate 5% AS is an ideal agent for regulating cabbage growth and increasing yield.

Approach of Obtaining Liquor Flavoring from Yellow Water Based on Electro-adsorption

This study was conducted to extract scarce natural liquor flavorings desired by many liquor factories from yellow water. Five straight-chain saturated fatty acids were firstly extracted from 15 fractions of yellow water, forming 1 fraction of the ethanol solution composed of the mixture of the five straight-chain saturated fatty acids. Then, 100 fractions of the ethanol solution could produce 94.857 6 fractions of esterification liquid through catalytic esterification at 80 ℃. The esterification liquid contains five esters： ethyl acetate, ethyl propionate, ethyl butyrate, ethyl valerate and ethyl caproate, with contents of 17.68%, 2.58%, 6.32%, 0.06% and 19.40%, respectively. The esterification liquid prepared from 1 fraction of yellow water could blend 10.54 fractions of white liquor into top-grade Luzhou-flavor liquor after esterification. It indicates that yellow water has very good recycling and utilization value.

Effects of a New-Type Cleaning Agent and a Plant Growth Regulator on Phytoextraction of Cadmium from a Contaminated Soil

In China, great efforts are being made to remediate farmlands polluted by heavy metals. In this study, a soil pot experiment was conducted to examine the effects of a new-type cleaning agent, methylglycinediacetic acid(MGDA), and a plant growth regulator(PGR), diethl aminoethyl hexanoate(DA-6), on plant growth and extraction and detoxification of cadmium(Cd) by ryegrass. The results showed that foliar spray of DA-6 alone improved plant growth, with root length and shoot dry biomass increased by 38.5%–58.6% and 71.1%–89.3%, respectively, whereas addition of MGDA alone decreased root length and shoot dry biomass by 10.3%–18.6%and 9.1%–21.8%, respectively. Diethl aminoethyl hexanoate promoted the binding of Cd to cell walls and thus alleviated the toxicity of Cd and/or MGDA to plants. Applications of DA-6 and/or MGDA resulted in a significant increase in Cd extraction efficiency(P < 0.05), and the efficiency decreased in the order of MGDA + DA-6 > DA-6 > MGDA. The treatment of MGDA + DA-6 achieved 2.2%, 1.7%, and 0.8% Cd extraction efficiency by ryegrass in soils spiked with 25, 50, 100 mg Cd kg^(-1), respectively. Therefore,treatment of MGDA + DA-6 could be an efficient method for enhancing phytoremediation of Cd-contaminated soil by ryegrass.

Effect of Surface Modification on Microbiol Polyhydroxyalkanoate Films on Biocompatibility

The purpose of this study was to investigate in vitro biocompatibility of a new type of polymer, polyhydroxybutyrate co hexanoate (PHBHHx). The hydrophilicity and biocompatibility were studied with two kinds of enzymes, amylase BAN480L and lipase Novozym388. The degree of hydrophilicity was observed using contact angle measurements. In vitro biocompatibility evaluations were carried out by direct incubation of mouse fibroblast cell line L929 on the polyhydroxyalkanoate (PHA) films. The samples treated with BAN480L showed that the PHA biocompatibility increased while the hydrophilicity decreased. Relative to untreated samples, the number of cells on the Novozym388 modified PHBHHx significant decrease as the hydrophilicity also decreased. The results indicated that other surface characteristics besides hydrophilicity influence the biocompatibility of PHBHHx films.

Effects of Applying New-style Growth Hormone on Eucalypt Cuttage

Diethyl aminoethyl hexanoate AC is a new-style growth hormone that induces cuttings to root by molecule signal. With Eucalptus urophylla and E. urophyllaxE, grandis as testing varieties, effects of applying different growth hormones on eucalypt cuttage were compared through experiments, and the result showed that diethyl aminoethyl hexanoate AC made cuttings root 4 days earlier than other common growth hormones did. The average rooting rate and the mean root quantity of diethyl aminoethyl hexanoate AC treated cuttings were 11%-26.5% higher than and 1.8-8.5 pieces per cutting more than those in other treatments. Besides, the seedlings were excellent. The new-style growth hormone improves cuttage of eucalypt to a higher level.