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Table of Content
24 April 1990, Volume 6 Issue 2
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Articles
Preparation and Structure of A Novel Ethanolamine-occluding Aluminoarsenate
Li Li, Vang Guangdi, Chen Jiesheng, Xu Ruren
1990, 6(2): 91-94.
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An aluminoarsenate, Al
2
As
2
O
3
·EAN, denoted as AlAsO
4
-1 was synthesized from EAN(EAN= ethanolamine), pyroarsenic acid and aluminium-iso-propylate systems. The crystal structure of AlAsO
4
-1 was determined by single crystal X-ray diffraction method. The compound crystallizes in orthorhombic space group Pcab with the unit cell constants:0=8.781(3), 6=10.261(3), c=20. 433(11) A .V=1840.9A
3
, 2=8. The final Rand Rw factors are 0.0401 and 0.0344, respectively. The framework of AlAsO
4
-1 contains two types of Al atoms. It is interesting that in the asymmetric unit one of two Al atoms is strictly 4-coordinated and the other is 6-coordinated. The three-dimensional framework is built of two-dimensional nets which consist of 4-membered rings and 8-membered rings. The biggest open channel in the framework runs along [100], in which EANtemplate is located. Arsenic atoms can function as a component element for construction of three-dimensional net with topological novelty.
Syntheses and Properties of K
17
[Ln(CuW
11
O
39
)
2
]·xH
2
O
Wang Enbo, Wu Qingyin, Huang Rudan, Hu Changwen
1990, 6(2): 95-101.
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Heteropoly-complexes K
17
[Ln(CuW
11
O
39
)
2
]·xH
2
O(Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Dy) were prepared. The properties of the products were investigated by ion-exchange, conductometric titration, IR, UVand X-ray powder diffraction. The results show that the structure of the products is similar to that of U(a-Ge
11
O
39
)
2
and consistent with the model proposed by Peacock.
Electrocatalysis of Metalloporphyrins(Ⅷ)——Electrocatalytic Reduction of Molecular Oxygen with Water-Soluble Cobalt (Ⅱ) Tetrakis(4-Trimethyl Ammonium Phenyl) Porphyrin Catalyst
Wang Zongli, Zhang Hui, Pang Daiwen
1990, 6(2): 102-109.
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Reported here is the electrocatalytic reduction of molecular oxygen in the presence of water-soluble cobalt(Ⅱ) tetrakis(4-trimethyl ammonium phenyl) porphyrin (Co(Ⅱ)TTAPP) as catalyst in solutions of various pHvalues. The overpotential of molecular oxygen reduction is reduced by ca. 200-400 mVin acidic and neutral solutions compared with several decades of millivolts in alkaline solutions, indicating that Co(Ⅱ)TTAPPpossesses much higher catalytic activity in acidic and neutral solutions than in alkaline. H
2
TTAPPin solutions of various pHexhibits no significant catalytic activity for oxygen reduction. The significant difference in the electrocatalytic activity of Co(Ⅱ)TTAPPfrom that of H
2
TTAPPfor oxygen reduction indicates that the electrocatalytic activity of Co(Ⅱ)TTAPPshould be attributed to the central cobalt atom (Co(Ⅱ)) coordinated by N4 internal ring in Co(Ⅱ)TTAPP. The total number of electrons involved in oxygen reduction electrocatalyzed by Co (Ⅱ)TTAPPis 2, and the product of such reaction is H
2
O
2
or HO
2
-
in solutions of various pH. The reaction mechanism of oxygen reduction in acidic and alkaline solutions is also discussed.
Different Behaviour of Gallium and Aluminium Exhibited in the Formation of Zeolite Frameworks
Liu Xinsheng, John M. Thomas
1990, 6(2): 110-117.
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Different behaviour of gallium and aluminium exhibited in the formation of zeolites such as L, of-fretite, omega, faujasite, F, A, J, W, and Hwas investigated. Effeects of Ga on the formation of these zeolite frameworks were observed on the stage of nucieation. In the co-presence of Ga and Al, Al plays a dominant role for the zeolite nucieation. The reasons for the different functions of Ga and Al are discussed.
The Oxidative Decarboxylation of Nitrilotriacetic Acid (NTA)——A Study of the Reaction of NTA with Cerium(Ⅳ) in HCIO
4
Ye Jingxian, Hanna S. B.
1990, 6(2): 118-123.
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The reaction between Ce (IV) and NTAwas investigated titrimetrically and spectrophotometrically. Two equivalents of Ce(IV) are reduced per mole of NTAalmost instantaneously at room temperature. With increasing reaction time an ultimate of about 7 equivalents of Ce(IV) is consumed per mole of NTAat room temperature. Carbon dioxide, formaldehyde and dimethylamine are the major and readily detectable products of oxidation of NTAby Ce(IV). The rates of the reaction in HClO
4
were measured spectrophotometricaUy using the stopped flow technique. The effects of both acidity of the medium and added salts support and extend preliminary results.
Synthesis and Structure Study of Molybdenum Complex Mo[o-NHCOCH
3
-m-NO
2
C
6
H
3
COOH]
2
O
2
Cl
2
·PhCl
Wu Lixin, Fan Yuguo, Guo Chunxiao, Sun Chunting, Huang Qijun, Liang Tianfei, Zhang Jingwen
1990, 6(2): 124-129.
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The crystal and molecular structures of molybdenum complex, Mo [o- NHCOCH
3
-m-NO
2
C
6
H
3
COOH]
2
O
2
Cl
2
·PhCl are reported. The crystal belongs to space group Cc of monoclinic system with unit cell parameters:α=11.214 (3) Å.b=19.544(4) Å . c=14.091(6)Å .β=94.06(3)°,V=3080.3 Å
3
and Z=4. The structure was refined to R=0. 061.The coordination number for the Mo atom Is six. The coordination polyhedron formed by four Oatoms and two Cl atoms around the Mo atom is a distorted octahedron. Four Oatoms and one Mo atom construct a plane. Two benzyl planes in coordinate groups and the benzyl plane of solvent are almost parallel. The quantum-chemical calculations were carried out. There are hydrogen bonds in the Complex. The EHMO calculations and the existence of hydrogen bonds prove that the Oatoms are stronger coordinated atoms in the carbonyls than in the carboxyls.
Studies of Unusual Oxidation States of Transition Metals Ⅱ——Kinetics and Mechanism of Oxidation of Pyruvate by Diperiodatoargentate (Ⅲ)Ion
Shi Tiesheng, Wang Zhipu
1990, 6(2): 130-134.
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The kinetics of oxidation of pyruvate by diperiodatoargentate(Ⅲ) ion (DPA) has been studied spec-trophotometrically in alkaline medium. It was found that the reaction order with respect to both DPAand pyruvate is unity and the rate equation can be expressed as -d[Ag(Ⅲ)]
1
/dl=k
0
[Ag(Ⅲ)]
1
·[CH
3
COCOO] The rate increases with the increase in [OH ] and decreases with the increase in [periodate]. There is a positive ionic strength effect in this reaction system. Amechanism has been proposed to explain the experimental results. The observed activation parameters are presented.
Ab Initio Study of the Dehydrogcnation of Methylenimine
Chen Bin, Zhao Chengda, Fu Qiang
1990, 6(2): 135-140.
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The ab initio calculations were performed by the intrinsic reaction coordinated(IRC) method for the reaction paths of the dehydrogenations of methylenimine. We determined the geometries and energies of the transition states and obtained the activation energies, activation entropies and the statistical Afactors on the RHF/4 -31Gsinglet potential energy surface. The mode selective study reveals the intrinsic reaction coordi-nates(URC) of 1,1 and 1,2 dehydrogenations of methylenimine to be related with the H
2
C= group symmetrical stretch mode and the =NHgroup stretch mode, respectively. The vibration coupling between the normal coordinates occurs in either of these two reaction paths.
Investigation of Mechanisms About Effects of Promoters P
2
O
5
,K
2
O and Al
2
O
3
on Oxidation of o-Xylene to Phthalic Anhydride
Zheng Xiaoming, He Weilian, Yuan Xianxin, Zhou Lichua, Jin Songshou
1990, 6(2): 141-148.
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We succeeded in designing an effective catalyst, V
2
O
5
-P
2
O
5
-K
2
O/Al
2
O
3
. SiO
2
, by which a high yield of PA,105wt% can be gained in middle-sized industrial fluidized bed apparatus without addition of any promoting gas.The mechanisms of effects of P
2
O
5
, K
2
Oand Al
2
O
3
on the surface properties of V2O
5
were investigated by means of TPDand XRD. And the selectivity of oxidation are explained.Addition of a great deal of P
2
O
5
restrains the activity of donating surface oxygen from V2O
5
, but increases the number of sites which donate surface oxygen. Addition of K
2
Opromotes donation of surface oxygen from V2O
6
, and decreases the number of sites of donating oxygen, on the other hand, addition of K|Omakes the surface structure of V
2
O
5
catalysts more stable. Coating a small amount of Al
2
O
2
onto support, SiO
2
, restrains the activity of donating oxygen and increases the number of sites of donating surface oxygen from V
2
O
5
.
Studies on the Graft Copolymerization of Methyl Acrylate and Ethyl Acrylate onto Corn Starch Using Potassium Persulfate-Sodium Thiosulphatc as Initiation System
Wu Gongsheng, Wang Bin
1990, 6(2): 149-154.
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Grafting copolymerizations of methyl acrylate(MA) and ethyl acrylate(EA) onto corn starch, respectively, initiated by potassium persulfate-sodium thiosulphate (KPS-STS) redox system, were studied. The structures of poly(MA)-g-starch and poly(EA)-g-starch were characterized by IR, SEMand X-ray diffraction. Experimental results show that KPS-STSis an efficient initiation system for grafting of MAand EAonto corn starch. The maximum percent grafting was obtained at [KPS] of 6.0×10
-5
mol/L, [STS] of 1.8×10
3
mol/L, [M] of 6.0×10
4
mol/L, S:L=4:100 at 40℃ for 6 h. The reactivity order is MA>EA.
Theoretical Studies on the Relationship Between the Structure and Property of Cellulose and Nitrocellulose--Nitration Activity and Mechanism
Xiao Heming, Fan Jianfen, Li Yongfu, Yu Hengtai
1990, 6(2): 155-159.
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Chemistry and Application of Phosphonium and Arsonium Ylides (XV)——A Facile Synthesis of Dimethyl 3,7-Diperfluoroalkyl-2,4,7-Nonatriendioates
Zhang Pingsheng, Ding Weiyu, Cao Weiguo
1990, 6(2): 160-163.
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)
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Editor-in-Chief:
Jihong YU
ISSN 1005-9040
CN 22-1183/O6
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