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101.
Converse A. O. Kwarteng I. K. Grethlein H. E. Ooshima H. 《Applied biochemistry and biotechnology》1989,(1):63-78
The results of an experimental study of the acid hydrolysis of hardwood are presented in the form of values for the three
parameters, activation energy, power on the acid concentration, and pre-exponen-tial factor, of the first order kinetic constants
for each of the following reaction participants: xylan remaining, glucan remaining, xylose formed, and xylose decomposed.
These are used as a base for a quantitative theory to predict the temperature, time, and acid concentrations needed for effective
pretreatment of the substrate for subsequent enzymatic hydrolysis of the glucan. This theory is based on the assumption that
successful pretreatment requires >90% removal of the xylan, <10% removal of the glucan, and >80% xylose yield. This theory
is compared with selected published data. 相似文献
102.
环氧乙烷(EO)和环氧丙烷(PO)共聚体系的等温结晶前期符合Avrami方程。PO组分含量增加,Avrami指数n值由1.8到2.4,体系的结晶生长速率与共聚体系的组成和结晶度有关,EO/PO共聚体系的平衡熔点随PO含量的增加而降低。随Tc增大,△Hm与△Sm呈线性降低。 相似文献
103.
R. F. Bakeeva L. Yu. Tartykova L. A. Kudryavtseva V. E. Bel'skii N. V. Usol'tseva B. E. Ivanov 《Russian Chemical Bulletin》1992,41(5):817-821
The kinetics of decomposition of p-nitrophenyldimethyl thiophosphate (1) were investigated spectrophotometrically in the n-decylammonium chloride-n-decylamine-water system (DAC-DA-H2O), in which micellar or lamellar liquid-crystalline phases are formed as a function of the concentration of components. It was shown that1 is dealkylated in both phases. An increase in the surface charge density of associates decreases the rate of dealkylation. The activation energy in the lamellar phase is significantly higher than in the micellar phase.A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan' Scientific Center, Russian Academy of Sciences, 420083 Kazan'. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 5, pp. 1042–1048, May, 1992. 相似文献
104.
Relationships have been established between the average conversion degree and the dissociation time for polydisperse granular
material, taking its grain size distribution into account. It has been checked in which cases the kinetic curves obtained
by a numerical solution can be described in terms of KEKAM equation.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
105.
The ethanol effect on the Trichoderma reesei cellulases was studied to quantify and clarify this inhibition type. To determine inhibition parameters of crude cellulase
and purified exoglucanase Cel7A, integrated Michaelis-Menten equations were used assuming the presence of two inhibitors:
cellobiose as the reaction product and ethanol as a possible bioproduct of cellulose fermentation.
It was found that hydrolysis of cellulose by crude enzyme follows a model that considers noncompetitive inhibition by ethanol,
whereas Cel7A is very slightly competitively inhibited. Crude cellulase is much more inhibited (K
iul=K
icl=151.9 mM) than exoglucanase Cel7A (K
icl=1.6 × 1015 mM). Also, calculated inhibition constants showed that cellobiose inhibition is more potent than ethanol inhibition both for
the crude enzyme as well as exoglucanase Cel7A. 相似文献
106.
107.
Yatsimirskii V. K. Oleksenko L. P. Lutsenko L. V. 《Theoretical and Experimental Chemistry》2004,40(1):44-51
We have studied the kinetic behavior of oxidation of carbon monoxide on Co-containing zeolite ZSM-5. We have shown that the kinetic curves obtained for the dependence of the reaction rate on the reagent concentration can be described by an Eley–Rideal mechanism, which assumes that oxygen can be adsorbed on the surface of the catalyst in both atomic and molecular form, followed by reaction of CO from the gas phase with the adsorbed oxygen. 相似文献
108.
V. V. Nedel'ko B. L. Korsounskii T. S. Larikova V. R. Stepanov N. V. Chukanov I. V. Nedel'ko 《Russian Chemical Bulletin》1994,43(11):1812-1815
The thermal decomposition of 1-ethyl-5-iodotetrazole in a melt and in solutions was studied using thermogravimetry, manometry, pyrolytic mass spectrometry, and IR spectroscopy. The kinetic and activation parameters of the process and the nature of the decomposition products were determined. The reaction mechanism is assumed to involve equilibrium tautomeric rearrangement of the tetrazole to azidoazomethine form followed by homolytic cleavage of the C-I bond.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1923–1926, November, 1994.The authors are grateful to O. A. Ivashkevich and P. N. Gaponic (Belarussian State University), who provided the samples of the tetrazole. 相似文献
109.
The synthesis of malachite CuCO3·Cu(OH)2 or Cu2CO3(OH)2 was studied through titrations of copper(II) salt solutions with a solution of sodium carbonate at different temperatures. The precipitates were characterized by TG, IR and chemical analysis. The composition varies depending on thepH of the solution and the temperature. Purer malachite was synthesized by simple mixing of a solution of copper(II) nitrate or sulfate with a solution of sodium carbonate at 50°C.The kinetics of the thermal decomposition of synthetic malachite was described by eitherR
3 orA
m(m=1.2–1.4) law, according to TG analysis, both isothermal and nonisothermal. The Arrhenius parameters determined using three different integral methods showed the kinetic compensation effect, which is correlated to the working temperature interval analyzed.The authors thank Mr. H. Takemoto for analyzing kinetics of the thermal decomposition of synthetic malachite. 相似文献
110.
用DSC研究纯三水铝石溶出动力学 总被引:1,自引:0,他引:1
在DSC上研究了NaOH溶液中合成三水铝石的溶出过程动力学。应用非等温反应动力学模型计算了动力学参数,分析和确定了反应机理。模型计算结果与用DSC测得的结果吻合。 相似文献