2024-03-28T15:02:28Z
https://ijcce.ac.ir/?_action=export&rf=summon&issue=1703
Iranian Journal of Chemistry and Chemical Engineering
Iran. J. Chem. Chem. Eng.
1021-9986
1021-9986
1996
15
1
Synthesis of New 10-Arylthioanthralins and Oxidation of Thioanthralins to Their Corresponding Sulfones
Jabbar
Khalafy
John Malcolm
Pruce
Treatment of 10-bromoanthralin (1) with several thiophenols (2) gave the corresponding 10-arylthioanthralins (3) in high yields. Oxidation of thioanthralins (3a-c) and (3k-m) using an excess of m-chloroperbenzoic acid gave the corresponding sulfones (4a-c) and (4k-m) in good yields. Oxidation of thioanthralins (3d-f) gave a mixture of the corresponding sulfones (4d-f) and anthralin-10,10'-dehydrodimer (5). Oxidation of thioanthralins (3g-j) afforded only anthralin-10,10'-dehydrodimer (5) with no evidence of sulfone.
Anthralin
Dithranol
Psoriasis
Anthrones
Thioanthralins
Sulfonylanthralins
1996
06
01
1
7
https://ijcce.ac.ir/article_10131_8b44d193d8109f0a4cae946b8b733d7e.pdf
Iranian Journal of Chemistry and Chemical Engineering
Iran. J. Chem. Chem. Eng.
1021-9986
1021-9986
1996
15
1
Cerium(IV) as Ceric Triethylammonium Nitrate: An Efficient Catalyst for Protection and Deprotection of Alcohols with Dihydropyran
Nasser
Iranpoor
Peyman
Slalehi
Catalytic amount of Ce(IV) as ceric triethylammonium nitrate (CTEAN) in dichloromethane or acetone can bring about an efficient tetrahydropyranylation of different types of alcohols to afford the corrsesponding tetrahydropyranyl ethers in high yields. Deportection of tetrahydropyranyl ethers can also be achieved efficiently in the presence of this catalyst in methanol.
Ceric ammonium nitrate
Dihydropyran
Protection
Deprotection
1996
06
01
8
10
https://ijcce.ac.ir/article_10132_5a62495d3f6121c1af66cc17c21781bd.pdf
Iranian Journal of Chemistry and Chemical Engineering
Iran. J. Chem. Chem. Eng.
1021-9986
1021-9986
1996
15
1
Oxidation of Ethylene to Ethylene Oxide by Selenium Modified Silver Catalyst
Fereydoon
Milani Nejad
Siranoush
Sharzad
A.
Bagher Zadeh
Oxidation of ethylene to ethylene oxide over silver catalyst and selenium modified catalyst has been studied by continuous flow and pulse techniques over the temperature range of 230-280 °C. The results are discussed in terms of reaction mechanisms proposed by others, rejecting mechanisms which involve peroxide formation. It has been shown that not only selectivity towards ethylene oxide production increases considerably by introduction of 0.01 atom percent of selenium into silver, but the reactivity increases also. Above 270 °C selectivity drops almost to the level of unmodified catalyst because selenium atoms diffuse into the grooves between silver crystals on the surface of catalyst. It has also been shown that intermolecular conversion of ethylene oxide to acetaldehyde decreases.
ethylene
ethylene oxide
Silver catalyst
Modified silver catalyst
Oxidation
Selenium
1996
06
01
11
17
https://ijcce.ac.ir/article_10343_1f062216276899855610cb9907c11eef.pdf
Iranian Journal of Chemistry and Chemical Engineering
Iran. J. Chem. Chem. Eng.
1021-9986
1021-9986
1996
15
1
Determination of the Very High Barriers to Conformational Processes by the Neat Racemization Technique. Part 1: Barriers to Ring Inversion in Dibenzo [a,c] Dinaphtho [2,3-e; 2,3-g] Cyclooctatetraene and Hindered Rotation in 2,2'-Dimethyl Binaphthyl
Parviz
Rashidi Ranjbar
Jan
Sandström
George W.
Schriver
Henry N.C.
Wong
A method is described by which it is possible to determine the high barrier to ring inversion and hindered rotation by neat racemization of optically active compounds when the racemization is caused by ring inversion or hindered rotation. The method is based preparation of sufficiently pure enantiomers, mainly by chromatography on swollen microcrystalline triacetylcellulose (TAC). By this technique the barrier to ring inversion in dibenzo [a,c] dinaphtho [2,3-e; 2,3-g] cyclooctatetraene, a tetrabenzocyclooctatetraene analogue, was determined to be 67.2±0.8 kcl/mol, a record as the highest conformational barrier ever reported. The barrier to hindered rotation in 2,2'-dimethyl binaphthyl was determined by this method to be 49.5±0.5 kcl/mol.
Racemization
High Barrier
Ring inversion
Hindered Rotation
Chiral Chromatography
Eight membered rings
1996
06
01
18
22
https://ijcce.ac.ir/article_10373_2a3304a5c80e6332d6335d6b2f5f40c9.pdf
Iranian Journal of Chemistry and Chemical Engineering
Iran. J. Chem. Chem. Eng.
1021-9986
1021-9986
1996
15
1
Coadsorption of Dioxygen and Carbon Monoxide on a Mg(100) Surface
Asghar
Zeini Isfahani
M.W
Roberts
A.F
Carley
S.
Read
The activation of carbon monoxide by oxygen on Mg(100) surface has been investigated by X-ray photoelectron spectroscopy (XPS). Carbon monoxide is only weakly adsorbed (dispersion-type forces) on a magnesium surface. The XPS result has shown that the dissociation of carbon monoxide leading to the formation of a metastable surface carbonate species occurs through the participation of an oxygen surface O¯(s). A stepwise mechanism involving a weakly adsorbed CO molecule present at very low surface coverage (<0.1) undergoing surface diffusion and interaction with the transient oxygen adatoms is suggested. The Frenkel equation has been used to estimate the mean residence time of CO molecule on the surface, and the residence time of a molecule on a specific surface site has also been estimated.
Coadsorption of CO+O2
Carbonate formation
Residence time of CO molecule
Transient species
Hopping mechanism
1996
06
01
23
27
https://ijcce.ac.ir/article_10374_4baa60e48e143a8c500fe0b37ec68ec3.pdf
Iranian Journal of Chemistry and Chemical Engineering
Iran. J. Chem. Chem. Eng.
1021-9986
1021-9986
1996
15
1
Polarographic Study of the Interactions between Thallium and Lead Ions and Some Crown Ethers in 90% Acetonitrile and 90% Ethanol Solutions
Mojtaba
Shamsipour
Abolfazl
Semnani
The complexation reactions between Tl+ and Pb2+ ions and crown ethers 12-crown-4(12C4), 15-crown-5 (15C5), benzo-15-crown-5 (B15C5), 18-crown-6 (18C6), dicyclohexyl-18-crown-6 (DC18C6) and aza-18-crown-6 (A18C6) were studied in 90% acetonitrile and 90% ethanol solutions at 25 °C, using an a.c. polarographic technique. The stoichiometry and stability of the complexes were determined by monitoring the shift in peak potential of the polarographic waves of metal ions against the crown concentration. The stability of the resulting 1:1 complexes of Tl+ and Pb2+ ions, in both solvent systems used, was found to vary in the order 18C6>DC18C6>18C6>15C5>B15C5>12C4. In 90% ethanol, Pb2+ ion complexes wih all crown ethers used were more stable than the corresponding Tl+ complexes. The influence of substituents in the polyether ring and of the nature of solvent and metal ions on the stability of a number of complexes is discussed.
Crown complexes
Thallium
Lead
Stoichiometry
stability
Polarography
1996
06
01
28
34
https://ijcce.ac.ir/article_10376_11946647e8a3fbf6dc201258dadf163e.pdf
Iranian Journal of Chemistry and Chemical Engineering
Iran. J. Chem. Chem. Eng.
1021-9986
1021-9986
1996
15
1
Deprotection of Benzyl and t-Butyl Phosphate, Phosphite, and Sulfite Esters by Silica Chloride
Farajollah
Mohanazadeh
Yousef
Ranjbar
Deprotection of phosphate, phosphate, and sulfite esters by silica chloride is described. Silica chloride is a mild, selective, and effective reagent for cleavage of benzyl and t-butyl esters of the above compounds.
Silica chloride
Deprotection
Phosphate ester
Phosphite ester
Sulfite ester
1996
06
01
35
37
https://ijcce.ac.ir/article_10378_3a09abfa20afbb2834054f566e99623f.pdf
Iranian Journal of Chemistry and Chemical Engineering
Iran. J. Chem. Chem. Eng.
1021-9986
1021-9986
1996
15
1
Automated Analysis of Pressure Build up Tests Affected by Phase Redistribution
Ali
Mohebbi
F.A.
Sobbi
Analytical Solutions and type curves for the constant rate radial flow of fluid in both conventional and naturally fractured reservoirs including the effect of wellbore phase redistribution are presented. An automated procedure for non-linear least square minimization using the analytical solutions and their derivatives with respect to the unknown parameters developed to analyze the pressure build up data affected by phase redistribution. Field examples and analysis are also presented.
Pressure build up test
Wellbore phase redistribution
Type curve
Optimization
Non-linear regression
1996
06
01
38
47
https://ijcce.ac.ir/article_10380_1ecf9972da22dd16521c27d88bdb76a5.pdf