Advanced Materials Research Vols. 634-638

Abstract: The silicotungstic acid catalyst supported on bentonite was employed in the esterification of menthol and lactic acid. The main reaction parameters were silicotungstic acid loading on bentonite, the amounts of catalyst, molar ratio of reactants, reaction temperature and reaction time. The optimum conditions were determined as follows : silicotungstic acid loading on bentonite 50 wt %, catalyst 1.25 g , mole ratio of menthol to lactic acid 1:1.1, reaction temperature 130 °C and reaction time 3 h . The esterification yield of menthyl lactiate was about 83.97 %. The catalyst could be used repeatedly for many times without distinct loss in activity.

Abstract: A new ionic liquid, N-octyl-2-pyrrolidonium chloride (NOPC), were synthesized and evaluated as inhibitors for mild steel (Q235) corrosion in 1 mol/L HCl. The adsorption behavior and corrosion inhibition mechanism of NOPC for mild steel in HCl solution were investigated by using weight loss measurements, electrochemical techniques, and SEM. The inhibition efficiency increases with the increasing concentration of NOPC in 1 mol/L HCl and decreases as the temperature increases. The results indicate that NOPC is able to function as a mixed type inhibitor.

Abstract: The inhibitory kinetics of isooctyl 4-hydroxy-3-methoxycinnamate on the activity of monophenolase and diphenolase contained in tyrosinase was studied by enzymological kinetic method with Na2HPO4-NaH2PO4 buffer solution (pH=6.8) at 30 °C. Isooctyl 4-hydroxy-3-methoxycinnamate was found to inhibit the monophenolase and diphenolase activity of tyrosinase well. The isooctyl 4-hydroxy-3-methoxycinnamate concentrations leading to 50 % inhibitory rate (IC50) were 0.24 mmol/L for monophenolase and 0.45 mmol/L for diphenolase, much less than that of arbutin (IC50 =5.3 mmol/L for diphenolase activity). Isooctyl 4-hydroxy-3-methoxycinnamate could extend the lag time of tyrosinase for oxidation of L-tyrosine, 0.4 mmol/L of isooctyl 4-hydroxy-3-methoxycinnamate resulted in the extension of lag time from 1.1 min to 3.6 min. The inhibition kinetics of isooctyl 4-hydroxy-3-methoxycinnamate analyzed by Lineweaver-Burk plots demonstrated a competitive inhibitor for the oxidation of L-DOPA, the apparent Michaelis comstant, Km, and the inhibition constant for inhibitor binding with enzyme, KI, were determined to be 0.45 mmol/L and 0.20 mmol/L respectively.

Abstract: Oligomerization of 1-butylene catalyzed by Bis(tetramethylcyclopentadienyl) Zirconium dichloride/MAO was investigated in detail under different conditions including reaction temperature, Al/Zr molar ratios, co-catalysts, concentration of catalyst to determine the optimal reaction conditions. The work shown that oligomer of 1-butylene in this catalyst system featured a kind of base oil of lubricant with pour point of -22 °C, kinematic viscosity of 2999 mm²/s at 40 °C and 2530 mm²/s at 100 °C, viscosity index of 258 and a moderate average molecular weight. In addition, the oligomer obtained was characterized by ¹H-NMR and IR.

Abstract: The oxidation of 2-methylnaphthalene(2-MN) to 2-methyl-1,4-naphthoquinone(2-MNQ, Vitamin K3) was accomplished in acetic acid with the application of hydrogen peroxide as oxidant. The yield of 2-MNQ was up to 81.3% when sulfuric acid used as catalyst. The catalyst exhibits excellent substrate conversion and target product selectivity. Different parameters affecting the oxidation of 2-methylnaphthalene with hydrogen peroxide catalyzed by sulfuric acid were described, such as reaction temperature, reaction time, dosage of hydrogen peroxide, and amount of sulfuric acid. Compared with the traditional methods for the preparation of Vitamin K3 with yield of only 30-50%, this method presented could be more effective, economical and ecofriendly.

Abstract: Cu-BTC was synthesized by hydrothermal method. Adsorption desulfurization performance of Cu-BTC for dibenzothiophene sulfide was investigated. The adsorption property of Cu-BTC for dibenzothiophene and 4-methyldibenzothiophene in stimulated diesel were compared by equilibrium and dynamic experiments. The results show that when the equilibrium concentration is 0~50 mg S/L, the adsorption capacity of Cu-BTC for 4-methyldibenzothiophene is more than that of dibenzothiophene. When the equilibrium concentration is 50 mg S/L, the equilibrium adsorption capacity of Cu-BTC for 4-methyldibenzothiophene and dibenzothiophene are 17.54 mg S/g_ads and 15.64 mg S/g_ads, respectively. At the conditions of 30°C, 149.22h^-1 and 0.1MPa, the initial concentration of dibenzothiophene and 4-methyldibenzothiophene is about 45.16~46.36 mg S/L, the adsorption property of 4-methyldibenzothiophene is superior than dibenzothiophene, the breakthrough capacity of Cu-BTC for 4-methyldibenzothiophehe is 1.73 times lager than dibenzothiophene. Cu-BTC shows an excellent prospect on diesel desulfurization process.

Abstract: The reactive theory of coking crude benzene hydro-refining process was analyzed generally. The results show that proper reaction temperature, system pressure, and hydrogen partial pressure are better for the hydro-refining reaction, and play a certain role in extending the service life of catalyst. With extending the service time of catalyst, the catalyst activity will reduce. The operating temperature and operating pressure need to be strengthened. When the catalyst has been aging, the product quality not is able to achieve the specified requirements, it is necessary to carry on the regeneration to the catalyst to restore its activity. In practice, the key parameters of hydrogenation have been controlled reasonably. While ensuring that the unit was safe and stable in continuous operation, it had a high recovery rate of the product, the product quality has been increased obviously.

Abstract: The decoloration of azo dye (Methyl Orange, MO) by a electrodeless discharge was analyzed. The discharge was generated under and above the pinhole(s) of the insulating plate, which was used to separate the electrodes. The effects of hydroxyl radical scavenger (sodium carbonate) and TiO2 on MO decoloration were studied. The results show that the decoloration rate of MO can be decreased by adding the carbonate ions to the solution, but it will be increased by adding the TiO2. The UV-Vis and FTIR spectras show that the azo bond (-N=N-) of the MO is broken up by corona discharge, and the phenyl-rings is further opened to form small molecular compounds such as organic acid.

Abstract: Some kinds of epoxy supports, LX1000-EP(C), LX1000-EP(D), LKZ-116, LKZ-118 and LKZ-126 were utilized to covalently immobilize cephalosporin C (CPC) acylase, the key enzyme in the one-step enzymatic process of 7-aminocephalosporanic acid (7-ACA) production. After preliminary carrier screening, the immobilized CPC acylase with LKZ-118 as the support shows the highest activity (115 U/g) suggesting its potential application in industrial 7-ACA production. The conditions of CPC acylase immobilized on LKZ-118 to achieve higher activity and thermostability of the immobilized enzyme were optimized by adjusting pH value, buffer concentration, enzyme dosage and immobilized time. The activity of immobilized enzyme was found to be optimal at pH 8.5, in 0.85 M sodium phosphate buffer when the enzyme dosage was 500 U/g and immobilization time was 28 h.

Abstract: In pipeline constructions especially for oil and gas, corrosion is a natural phenomenon which cannot be avoided but can be reduced. There are many kinds of corrosion protection can be used in this area and inhibition is one of it. At present inhibitors used commonly from chemical kind. This kind of inhibitor is expansive and toxic. The knowledge of plant substances have opened a new era of inhibitors. Research has proved that inhibitor can be made from plants which are rich in antioxidant and tannin. This research is conducted to see the inhibition mechanism of several plants which are rich in antioxidant and tannin. The plants used as inhibitors in this research are: manikara zapota; garcinia mangostana l., and ipomea batatas. Corrosion test are applied to API-5L in produce water environment. The conclusions of this research show that it is possible to use plants as inhibitor and when it is used as inhibitor every plant has their own mechanism.