VOLUME 3, NO3, SEPT 1981
12
 
The Radiation Chemistry of Water

K A KHAN ,

The radiation chemistry of water is described. Primary processes in the radiolysis of liquid water, their time scale, yields of primary species at different pH values and their properties are given. Physical properties of hydrated electrons and rate constants for the reactions of primary species are also given.
Pages(105)
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Preparation of new Benzimidazoles of Carbonyl Compounds Based on their Reaction with Hydroxylamine

F LATIF ,M AMJAD ,M HASSAN ,

Preparation, physical properties, infra-red and mass-spectra of two new benzimida· zoles, namely (4) and (5) have been described. Since these new benzimidazoles have structure ana­logous with the three benzimidazoles described in the first paper of this series, and differe from them in the absene of v-hydroxyl group in their structure, determination of their pharmacological activities will help in establishing the structl!re-reactivity relationship.
Pages(111)
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Indirect Polarographic Determination of Carbonyl Compounds Based on Their Reaction with Hydroxylamine

I Z AL ZAMIL ,M A AL HAJJAJI ,

Methods for the determination of carbonyl compounds based on their ability to dimi­nish the hydroxylamine anodic wave are described. The necessity of adding a proton acceptor in the determination of ketones is illustrated. The rapid direct current (d.c.) and the alternating current (a. c.) polarographic techniques were applied for the determination of 2-8 x 104M and 1-6 x 1O-5M car­bonyl compounds, respectively, with a reproducibility of ± 1.4%. These methods are shown to be suit­able for total carbonyl group determination.
Pages(115)
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Behaviour of aCationic Micelle on the Hydrolysis of Procaine Formulation

N RIZVI ,A E BEG ,

The kinetic investigation into the effect of cetyltrimethylammonium bromide (CTAB) on the base-catalysed hydrolysis of procaine has been studied. These studied were carried out at pH 9.1 in the temperature range of 50° - 80°. Using accelerated stability analysis the shelf-life of procaine at 25° in absence and presence of cationic surfactant CTAB at various concentration has been evaluated.
Pages(121)
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Kinetics of Catalyzed Redox Reaction Between Acrylic Acid and Peroxydisulphate

G M KHAN ,M I KHALIL ,

The redox reaction between acrylic acid and peroxydisulphate, catalyzed by Ag(l), has been studied kinetically over the range 35 to 55°C. The reaction products have been analyzed and a mechanism is proposed for the reaction. The rate law is deduced from this mechanism.
Pages(125)
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Detremination of Soluble and Insoluble Pentosans in Wheat Flour

M ALAM ,

A method is given for the determination of soluble and insoluble pentosans in wheat flour. The method involves a modified hydrochloric acid distillation procedure followed by furfural colorimetric measurement. Arabinose produced the same colour as xylose but gave lower recoveries. L-Arabinose was found by paper chromatography to be present in substantial quantity in relation to D-xylose in the Queensland wheat flour.
Pages(129)
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Synthetic Studies on peganum harmala Alkaloids Part I. New Derivatives of Harmol

N SULTANA ,A MALIK ,S Z SIDDIQUI ,

Structure and activity correlationship studies in hannol have yielded a number of new derivatives; their structures have been established through chemical characterization and spectral data.
Pages(135)
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Hydroxide Ion Catalysed Hydrolysis of Diartyl Phosphates

M YOUNAS ,A RAHMAN ,M IQBAL ,

Hydroxide ion catalysed hydrolysis of a series of diaryl phosphates with varying leav­ing groups, has been studied in water at 390C and an ionic strength of 1.0. Mechanism involves a bimo­locular nucleophilic attack of the hydroxide ion concerted with the departure of the leaving group. A linear free energy relationship has been determined with a slope of -0.68 for a logarithmic plot of the second-order rate cosntants for the hydrolysis, against the pK of the leaving groups.
Pages(139)
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Reaction of Isomeric Methyl Ethers of Triacetic Lactone

P F G PRAILL ,M SIDDIQ ,A W KHAN ,

Reactions of isomeric methyl ethers (2a) and (3a) of triacetic lactone (1) with phos­phorus pentasulphide have been found to yield the thiiderivative (2b) and (4a) respectively. Using aq­ueous solutions of secondary arnines the methyl ether (2a) and its thioanalogue (2b) have been converted into 4-substituted 6-methyl-2H-pyrm-2-ones (2d-O and 2H-pyran-2-thiones (2g-i) respectively. The 2H-pyrqn-2-tiones (2g-l) were isomerised into thiopyrm-2-ones (2j-1). In all these reactions the nu­cleophillic attack occurs at the 4 or 4,2-positions of the ethers. Thiopyrarn-2-ones (2j-l) on treatment with phosphorus pentasulphide gave the corresponding thio pyram- 2-thiones (2m-o). The spectroscopic data of the compounds are recorded.
Pages(143)
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Normal Coordinate Analysis of 1,3 Dioxole-2-Thione

K IQBAL ,

Infrared and Raman data of 1,3 dioxole-2-one, CH=CH-O·C(O)-O (vinylene carbo­nate) has been analysed through a normal coordinate calculations to give a better vibrational assign­ment and a force field for this molecule.
Pages(149)
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