Iranian Journal of Chemistry and Chemical Engineering
Volume:13 Issue: 2, Nov-Dec 1994

We have recently synthesized Ti(BH4)3 (THF)3 and V(BH4)2(TMEDA)2complexes. The reaction of TiCl3(THF)3 with NaBH4 in dry THF gave flat blue crystals, Ti(BH4)3 (THF)3. The reaction of VCl3 with NaBH4 in presence of N, N,, – tetramethylethylenediamine, TMEDA, produced violet crystal, V(BH4)2(TMEDA)2. Vibrational and magnetic properties of Ti(BH4)3 (THF)3 and V(BH4)2(TMEDA)2 have been studied.

Conformational properties of N-aryl-1-azacyclooctan-5-ones with a p-methyl-, m-methyl-, and p-meghoxy group as a substituent have been studied by 1H-NMR, 13C-NMR and IR spectriscopies. Transannular interaction of the two functional groups have been examined from the ring inversion barriers and the carbonyl vibrational frequencies with reference to the corresponding data of the respective monofunctional and difunctional compounds.

Para-Aminobenzoic acid is supported on silica gel via reaction of activated silica gel and p-aminobenzoic acid which is then converted converted to its manganese and cobalt salts. A mixture of the manganese and cobalt salts of the acid is used to catalyze allylic and benzylic alcohols to their corresponding carbonyl compounds in reasonable yields using oxygen or air. Reactions are clean and the catalysts can be recovered easily and reused repeatedly.

They synthesis and characterization of some new binuclear copper(II) complexes, based on the use of large, pyrole-containing macrocycles, the so called “expanded porphyins”, [Cu2(macrocycle)]+4 is described. Electron SpinResonance IESR) studies indicate a weak “half-filed lin”, which is characteristic of the Cu(II)-Cu(II) dimmer, is observed at about 1600G. The observation of this band strongly suggests that the hyperfine structure arises from a spin triplet species.

A simple and sensitive extraction-fluorimetric method for the determination of copper is reported. The 1,7 – diaza – 15 – crown – 5 – copper – rose Bengal (DA15C5-Cu-RB) ternary complex is quantitatively extracted into chloroform, diluted with ammoniacal acetone and its fluorescence internsity is measured at 570nm with excitation at 540nm. A linear calibration graph was obtained over the copper concentration range of 0.05-0.50mg/mL. The relative standard deviation for 0.35 mg/mL copper is 3.9%. The interfering effect of a large number of diverse ions on the determination of copper was studied. The method was applied to the determination of copper in tap water.

A kinetic spectrophotometric method for rapid measurement of thiocyanate in serum, urine and sewage water with no need for removed of interfering substances is described. The method is based on the inhibitory effect of thiocyanate on the oxidation of pyrogallol red by bromate and nitrite which is monitored at 467nm. The variables affecting the rate of the reaction were investigated and the optimum conditions were established. Thiocyanate can be measured in the range of 0.10-0.500mg/mL with a limit of detection of 0.001mg/mL. The reactive standard deviation for ten replicate determination of 0.025mg/mL of thiocyanate is 1.5%.

Hydrogenation reaction with n-heptane on Pt/Al2O3 catalyst was investigated under the steady state condition in a fixed bed reactor. The catalyst was prepared under a variety of conditions, byt the one chosen was non-acidic that is not considered a hydrocracking catalyst. The main objective was to vary the selectivity on n-heptane as a function of reaction variables especially the partial pressure of hydrogen, because in addition to hydrogenolysis, other reactions like isomerization and cyclization also take place. Our studies on selectivity of n-heptane on platinium catalyst shows that in general cracking reactions preferably yield propane and n-hutane, and at high pressures methane is also produce as a result of further cracking reactions. Products formed at low pressures (2-10atm) are: 3-methyl-hexane and 2,3-dimethyl pentane. Those produced with lower yields at higher pressures (20-40atm) were predominantly 2-methyl hexane and 3-methyl hexan. Dominant cyclic products were 1 tr 2-dimethylcyclopentane, toluene, methylcyclohexane, and ethyl cyclopentane. Upon increasing the hydrogen partial pressure, 1 tr 2-dimethyl cyclopentane increases strongly and those of six membered rings decrease.

Methyl tertiary butyl ether (MTBE) is known as a promising substitute for tetra ethyl lead (TEL) in order to increase the octane number of gasoline. MTBE process, as many other processes, has two distinguished section, namely reaction section and separation section. In order to achieve this objective, many possible flowsheets have been considered, amongwhich, two alternatives are pointed out as optimum candidates. The second step involves determination of dominant design variables and their ranges of variation. Both selected flowsheets have been cost analyzed in their corresponding ranges of dominant design variables to determine plots of total annual cost (TAC). Knowing feed specifications at the entrance of separation section, the designer will be able to choose appropriate flowsheet and optimum conditions using the plots presented in this paper.