VOLUME 10, NO3, SEPT 1988

POLAROGRAPHIC-BEHAVIOR OF SOME SULFONIC-ARYL-HYDRAZONO PYRAZOLIN-5-ONE DYES

Polarographic studies of some sulphonic aryl (or napthol) hydrazono -1-phenyl-3-methyl-2-pyrazolin-5-one have been carried out in 10% ethyl alco­hol B.R. buffer solutions in the pH range 1.8 - 12.0. The number of reduction waves was found to depend on the pH value of the solution and the structure of the dye stuff. All the compounds gave a single, well defined irreversible wave between pH values 2.0-9.0. The E~ of this wave is pH dependent but itsremains almost constant throughout the entire pH range. The E~ was shifted towards more negative potential showing that protonation preceeds reduction. The sulphonic group causes a shift of the wave and plateau suffers a minimum at pH value higher than 9.0. The reduction corresponds to consumption of four electrons leading to the amine stage. A general mechanism for the reduction process is suggested and discussed.read more

---

F I ZIDAN ,B A EL SHETARY ,S L STEVAN ,M S A MOEZ ,

STABILITY OF METAL-CHELATES OF 2-SULFONIC-4-METHYL PHENYLHYDRAZONO DIETHYLMALONATE IN VARIOUS MIXED AQUEOUS SOLVENTS

pH-meteric studies have been carried out to determine the dissocia­tion constant of 2-Sulphonic-4-methyl phenyl-hydrazono di-ethylmalonate abb­reviated (2-SPHDEM) 1 igand, as well as, the stability constants of its com­plexes with trivalent lanthanides and some divalent metal ions in various mixed aqueous solvents, viz: ethanol-water, methanol-water and dioxane-wate~ at 25°C and 0.1 M ionic strength. The dissociation constant of ligand decrea­ses (increase in acidity) by increasing the dielectric constant of the solvent. The stability constants of 1:1 and 1:2 chelates with trivalent lanthanides have been determined in 50'; (v/v) ethanol-water solvent. The effect of variation of the dielectric constant of different mixed aqueous solvents on the stability of chelate compounds of divalent metal ions was studied and discussed. The stability of these chelates follows the order: dioxane-water> ethanol-water> methanol-water.read more

---

F I ZIDAN ,A SALMAN ,N EL KHOLY ,B A EL SHETARY ,

SPECTROSCOPIC STUDIES OF LIGNINS FROM WHEAT STRAW AND KAI GRASS

Lignins were isolated from wheat straw and kai grass. Their IR, UV IH-NMR and Mass spectra were recorded to classify these compounds. The spec­troscopic results indicate that these lignins are composed of guaiacyl-syrin­gly unit and consequently the materials may be considered as the me~bers of hardwood family.read more

---

M AHMAD ,L KHAN ,

THERMODYNAMICS OF MOLECULAR ASSOCIATION OF ALCOHOLS AND KETONES

Studies on the molecular association of some alcohols and ketones, separately, and with each other were performed in the two different solvents diphenyl methane and tetradecane. The investigations were carried out at 25, 35 and 45°C, using a simple vapour pressure technique. The computed thermody­namic functions of these reactions are reported and the solvent effects have been discussed.read more

---

A A TAHA ,W S HEGAZI ,A A EMARA ,H S MAZHAR ,

NITRATION OF HECTORS BASE

Nitration of Hector's Base gives both mono and dinitro products. In each case, only one out of two phenyl rings involves in the nitration process and that ring is the 3-anilino portion of the Hector's Base. The protonation of the exocyc 1 i c nitrogen of Hector's base seems to deacti vate the phenyl ring attached to nitrogen at position 4, which in turn, does not react with nitronium ion. Finally, acetylation of nitrocompounds of Hector's Base and nitration of Hector's Base in acetylating mixture have also been discussed.read more

---

I HUSSAIN ,A R BUTLER ,

SYNTHESIS AND REACTIONS OF 4, 6-DIARYL-2,3,4,5-TETRAHYDROPYRIDAZIN-3-ONES

The hitherto unknown 4,6-diaryl-2,3,4,S-tetrahydro-pyridazin-3-ones (I I )were synthesi sed from the a.-aryl, l3-aroyl propi oni c aci ds (I )either by their reaction with hydrazine hydrate or by their conversion tOa,y-diaryl- The 3-chl oropyri dazi ne was treated either wi th sodi urn azi de produci ng the tetrazolopyridazine derivative (V) or with acylhydrazines to give the triazo­lopyridazine derivatives (VI). 3-Acylpyridazines (VII)were obtained on trea tment of (I I) with acetyl ch 1 ori de. (I I)a was converted to its corres­pondi ng thi one (V I I I), a 1 so reacted with benzyl ami ne gi vi ng 3-N-benzyl pyri da­zine (IX). (II)a was dehydrogenated to the corresponding dihydropyridazinone (X) •read more

---

A A AFIFY ,A A EL KHAMRY ,A Y SOLIMAN ,M A SAYED ,E A KASSAB ,

THE NEWTONIAN VISCOSITY OF POLYMER-SOLUTIONS - OVER A WIDE-RANGE OF CONCENTRATIONS

Viscosity of three polymers, namely polyisobutylene, cellulose acetate and polyschizophyllan, having different degree of flexibility is investigated over a wide range of concentrations and molecular weights. The data so obtained show a smooth variation in viscosity with respect to concentration of the polymers. The relationship betwe~n molecular weight of polymers and intrinsic viscosity or characteristic concentration, cch isobtained, by fitting the data to method of least squares. The cch values of the polymers were calculated using Graessley and Simha et al. models. Log n vs c/ c ch or c[n] were plotted to get the superpos it i on curves for every polymer. Where n is the reduced viscosity of the polymers. The data show that the deviations from these curves increase with the increase in rigidity of the polymer and it was not possible to scale the polyschizophyllan data using either of the above mentioned models. The data further show that the Graessley model is better than the others.read more

---

M K BALOCH ,

SOME REACTIONS OF ENAMINES

Tetrabromo-£-benzoquinone reacts with l-(cyclopentenyl) piperidine and l-(1-cyclohexenyl) piperidine to give the open (1:1) adduct (Ia,b) or (I'a,b), whereas it reacts with 4-(l-cyclopentenyl) morpholine to give the open (1: 1) addition product (I c or I' c) together with the cycl i c (1: 1) addition product (1Ia or Il'a). However, it reacts with 4-(l-cyclohexenyl) morpholine to give the cyclic (1:1) addition product (lib or II'b).read more

---

N G KANDILE ,T M A LATIF ,

SYNTHESES AND CHARACTERIZATION OF SOME 2-TRIHALOGENO-METHYL-SYM-TRIAZOLO [1,5-A]PYRIDINE

Some novel 2-trihalogenomethyl-8-nitro-s-triazolo[1,5-~]pyridines of potential interest as radiosensitizer have been prepared from,2-hydrazino-3­nitropyridine in condensation with trifluoroacetic anhydride, trichloroacetic and tribromoacetic acids respectively. These compounds are characterized by spectral techniques.read more

---

M MOAZZAM ,J PARRICK ,

SYNTHESIS OF SYMMETRICAL AZO DYES FROM 4,4'-DIAMINO-DIPHENYLAMINE-2-SULPHONIC ACID

Synthesis of some bis-azo dyes based on 4,4'-diamino-diphenylamine­2-sulphonic acid has been described. The properties of these dyes have been compared with similar dyes derived from benzidine. Since benzidine is one of the established carcinogens, the possibility to replace it with 4,4'­diamino-diphenylamine-2-sulphonic acid for the production of some direct dyes has been studied.read more

---

M YOUNAS ,M A SAEED ,M FAROOQ ,F SHAFI ,B UDDIN ,