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1.
 Based on the property that carboxymethylcellulose (CMC ) can be de-graded to anhydroglucose residues by cellulase, the rate constant (K) of enzymatic degra-dation of CMC synthesized in the benzene-ethanol medium has been determined. Further-morel experimental equation K = 2.71× 10-2(DS)-1.2 reflecting the relationship betweenK and the degree of substitution (DS) is correlated and used to describe chemical mi-crostructure uniformity of the distribution of substituents along chains effectively. Chain structure parameters of enzymatic degradation products of CMC — the number of chain breaks and the percentage of glucose released have been also measured.Average length of substituted and unsubstituted chain segments are calculated simultaneously.Through the study of static and dynamic procedures of enzymatic degradation,the method to characterize the distribution of substituents of CMC along the chain has been improved.  相似文献   

2.
Four new paranmeters, and , and have been proposed to describe the average length of the sequence of substituted anhydroglucose units and that of unsubstituted ones respectively along the CMC chain. The methods for determining those parameters have also been presented . Six CMC samples have been characterized in terms of intrinsic viscosity, degree of substitution (DS), index of substitution(SI)_ and . It has been proved experimentally that, not only can describe the sequence distribution along the CMC chain, but also can be used for calculating SI and estimating the average degree of substitution in the substituted glucose rings.  相似文献   

3.
The immunomodulation of several Charged synthetic polymers containing phosphorus in the backbone was studied in vitro through examining their inhibition or promotion effect on the proliferatioin of both T and B lymphocytes,It is found that polymers based on long chain alkyl ester of tyrosine exhibit immunomodulative activity.Negatively charged polymers show stimulative activity on LPS-induced B lymphocytes proliferation.Positively charged polymers exhibit inhibitory activity on both Con A-induced T lymphocytes and LPS-induced B lymplhyocytes proliferation.  相似文献   

4.
<正> The title compound (PAP) with excellent nonlinear optical prpper-ties has been synthesized. CHCHSCOO , monoclinic with space group P21, a = 4. 521(1), b = 9.601(6), c=17. 892(2)(?) , β=96. 12(1)°, V =772.8(?)3, Z = 2, Dc=1.44g · cm-3, F(000)-348, μ= 1.24cm-1. The second-harmonic intensities of PAP, MAP and NaAP HAP were measured,with the values which are 100, 50, 5. 0 times as large as that of KDP, respectively, Indicating that PAP is a new NLO crystal.  相似文献   

5.
The configuration of[PdCl_2(C_2H_4OH)]~- has been studied bypseudopotential ab initio method.A cis isomer was found to be the reactionintermediate in the Wacker process.  相似文献   

6.
<正> INTRODUCTION. Tripterygium hypoglaucum(Levl)Hutch growing in Hunan,Guangxi,Yunan and Guizhou provinces of China is a plant used as a medicinetreating rheumarthritis. All alkaloids contained within this plant arecharacterzed by antiinflammatory and analgetic. Using column partitionchromatography of silica gel, we have separated out the wilforine and wilforgine from root of this plant.  相似文献   

7.
Two possible complexes formed by the interaction of CH_3OH and H_2CO,one hydrogen-bonded(Ⅰ)and one donor-acceptor complex(Ⅱ),have been reported in the previous paper.Based on theab initio 6-31G basis set calculations,the properties of the charge density for the complexeshave beenanalyzed using the theory of atoms in molecules.The nature of the complex formation has beendiscussed in terms of the properties of the charge density distributions.  相似文献   

8.
探索了非缓冲条件下,用酒石酸对超稳Y型分子筛进一步脱铝改性的可能性。系统地考察了反应时间、反应温度、酒石酸溶液加入量、溶剂加入量、滴加速度及溶液pH值对处理过程的影响,并对改性后的分子筛样品采用X射线衍射测试、差热分析等手段进行了结构与性能的表征。结果表明,所用的分子筛脱铝方法在合适的处理条件下能制备出硅铝比达12左右的超稳Y型分子筛。改性后的超稳Y型分子筛的晶体结构热稳定性随着骨架硅铝比的提高而增加。  相似文献   

9.
The complex [(C_6H_5)_2PCH_2CH_2P(C_6H_5)_2]Fe (NO)_2, was easily synthesized by the reaction of Fe (CO)_5, NaNO_2 and (C_6H_5)_2PCH_2CH_2P(C_6H_5)_2 (dppe) in methanol and determined by X—ray diffraction which denoted that the title complex has two crystallographically independent molecules in its asymmetric unit.  相似文献   

10.
<正> INTRODUCTION. The derivatives of ferrocene are found to be increasingly used in the area of the catalysis of combustion reactions of high energy fuels and new material research. Therefore, more attention has been paid to these compounds. This work is a part of our systematic investigation on a  相似文献   

11.
In this paper, a new complex {Mo[S_2CN(C_2H_5)_2]_4}~( 1){FeCl}~(-1){C_6H_5CH_2SSCH_2C_6H_5} is syn-thesized by the reaction of MoCl_5, FeCl_3, PhCH_2SH and diethyldithiocarbamate (DTC)in MeOH. The complex is characterized by X-ray, IR, UV-visible, reflection spectra, themeasurements of magnetic susceptibility, differential thermal and elemental analyses. The crystal of triadic complex containing multi-bond species is quite stable and rare.  相似文献   

12.
The chemiluminescence (CL)behavior of luminol—H_2O_2—CIO~- system was studied,and the CL system can be used todetermine hydrogen peroxide(H_2O_2).Optimium data for thedetermination of H_2O_2 were provided and the effect of foreign ionswas also discussed.  相似文献   

13.
Our objectives were to develop a new chemical method for the polymerization of pyrrole. CuCl_2 dissolved in C_2H_5OH solvent is primarily used for the initiation polymerization of pyrrole. The polymers with different yield and conductivity were obtained by raring the initial concentration of Cu~(2+). The initial concentrations of Cu~(2+) varied from 1.2 ×10~(-4) mole to 6.48 ×10~(-3) mole Cu~(2+) with 2.16 ×10~(-2) mole pyrrole. The polypyrrole obtained was characterized with elemental analyzer, XPS, IR spectroscopy, Four-point probe and SEM.  相似文献   

14.
SYNTHEIS,SITUCTUREANDCHARACTERIZATIONOFBINUCLEARCu(II)COMPLEX[Cu(C_6H_5COO)_2(C_5H_6N_2)]_2.(C_4H_8O)_2¥RuiNaYANGandDouManJIN(Hena...  相似文献   

15.
1 INTRODUCTIONCoordination compounds with 1 ,2 ,4 triazole as a ligand have interesting fea tures,notonly because ofthe very interesting magnetic propertiesofthese complex es,but also because ofrich modes ofcoordination〔1〕.Particularly,the coordinationbehavioroftriazoletowardsa numberoftransition metalthiocyanatesshowsremark abledifferences〔2 - 6〕.On unsubstitution at N4 ,thetriazole ring hasmonodentate,1 ,2 and 2 ,4 bridging forms.These three modes were all observed in the Ni( II)…  相似文献   

16.
The title compound of Cu(C14H9O3)2(C5H5N)2(C2H5OH)2(1) was synthesized via the hy- drothermal reaction of CuCl2·2H2O and 9-hydroxy-fluorene-9-carboxylic acid(HHF) with pyridine, and characterized by elemental analysis and infrared spectra. The crystal belongs to triclinic, space group P1 with a = 8.8302(12), b = 10.1625(14), c = 12.2708(17), α = 86.207(2), β = 69.562(2), γ = 64.932(2)o, V = 930.3(2) 3, Z = 1, Mr = 764.30, Dc = 1.364 g/cm3, F(000) = 399, S = 1.059 and μ(MoKα) = 0.644 mm-1. The final R = 0.0459 and wR = 0.1274 for 3414 observed reflections with I 2σ(I). The copper atom is six-coordinated by two oxygen atoms from two different 9-hydroxy-fluorene-9-carboxylate ligands, two pyridine nitrogen atoms and two ethanol oxygen atoms, forming a distorted octahedral coordination geometry. The extensive O–H···O hydrogen bonding connects the molecules to form a one-dimensional chain structure. Between adjacent one-dimensional chains, a two-dimensional layered structure was formed by fluorene ring π-π packing interaction. Between the layers, a three-dimensional structure was formed through the π-π packing interaction of the pyridine ring. Moreover, the thermal stability and photoluminescent property of the complex has been investigated.  相似文献   

17.
(CH_3C_5H_4)Zr(S_2CNBz_2)_3, Mr=987.55, space group P1, a=13.002(4), b=13.659(3), c=29.685(8); α=100.72(2)~o,β=97.23(2)~o, γ=105.36(2)~o; V=4909(2)~3, Z=4, Dc=1.34gcm~(-3), Mo-K(λ=0.71073A) radiation, μ=5.0cm~(-1), R=0.069, Rw=0.078 for 6100 reflections. The title complex has pentagonal bipyramid configuration in which the zirconium atom is coordinated by one CH_3C_5H_4 group and three bidentate dibenzyldithiocarbamate ligands.  相似文献   

18.
In this paper it is demonstrated that (~3H)2'-5'P_3A_3 can bind to the peritoneal macrophages from Wistar rat. This binding is strongly inhibited by cold 2'-5'P_3A_3 while the inhibiting capacity of 2'-5'P_3I_3 and 2'-5'A_3 is very small, showing that this binding is highly specific. And the binding of (~3H)2'-5'P_3A_3 is reversible, saturable and with high affinity. A Scatchard analysis of the binding data gives a linear plot, an apparent dissociation constant (Kd) about 1.3×10~(-7) M and binding sites per cell about 2.1×10~7. The above evidence shows the existence of the 2'-5'P_3A_3 receptor, a fact which, to our knowledge, has not been reported before.  相似文献   

19.
<正> [Er(SSA)(H2O)7][Er(SSA)2(H2O)6]·8H2O (H2SSA = 5-sul-fosalicylic acid), Mr=1361.3, monoclinic,P21/c, a = 21.459(7), b = 10.125(2), c = 22. 033(5)(?), β=109. 07(2)°, V = 4524(2)(?)3, Z = 4, D,= 1. 998g/cm3, μ (MoKa) = 40. 6cm-1, F(000)=2704, R = 0. 038 for 5805 observed reflections. The Er(Ⅲ) ions in-both complex cation and anion are coordinated by unidentate SSA ligand(s) and water molecules in a trigondodecahedral geometry. The coordination polyhedra are connected with each other by hydrogen bonds involving the uncoordinated carboxylato oxygen atoms and the coordinated water molecules. Stacking interactions between the phenyl rings further stabilize the structure.  相似文献   

20.
<正> INTRODUCTION. Recently, researches on carbene metal complexes are very active, as they are of great importance in both theoretical study and catalytic activity. In a systematic research, the crystal structure of the title complex was analyzed and reported here to the advantage of understanding the catalytic action and searching for new and better carbene catalysts of novel kinds.  相似文献   

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