Applied Petrochemical Research (v.3, #1-2)
Study the efficiency of some compounds as lubricating oil additives by Rasha S. Kamal; Nehal S. Ahmed; Amal M. Nasser (1-8).
In the present work, some Mannich bases have been prepared by using different polyethylenepolyamines. Phosphosulphurized Mannich bases have been also prepared by reaction of prepared Mannich bases with P2S5. Structure of the prepared compounds was confirmed by infrared spectroscopy and the molecular weights determination. The efficiency of the prepared additives as antioxidants and detergents/dispersants was investigated. It was found that the efficiency increases with increasing the NH groups in the amine used. The best prepared additive as antioxidant and detergent/dispersant was obtained by using triethylenetetramine.
Keywords: Mannich base lube oil additives; Antioxidants; Detergents/dispersants
Acidic and cesium salts of polyoxometalates with and without vanadium supported on MCM-41 as catalysts for oxidation of cyclohexane with H2O2 by W. Trakarnpruk; J. Jatupisarnpong (9-15).
Acidic and cesium salts of polyoxometalate (POM) with and without vanadium supported on MCM-41 were synthesized and their catalytic activities were investigated in the oxidation of cyclohexane with H2O2 under solvent-free condition. The products are cyclohexanol and cyclohexanone. The catalytic activity order is: CsVPOM/MCM > HVPOM/MCM > CsPOM/MCM ~ HPOM/MCM > CsVPOM > CsPOM catalysts. High conversion and selectivity to cyclohexanone over the supported catalysts are due to redox property and high surface area. These heterogeneous catalysts can be reused.
Keywords: Polyoxometalate; Oxidation; Cyclohexane; Hydrogen peroxide
Studies of amino acids for inhibition of aldol condensation and dissolution of polymeric product of aldehyde in alkaline media by Hiren M. Bhajiwala; Harshad R. Patil; Virendrakumar Gupta (17-23).
Compounds with acidic and basic functional groups (aspartic acid, arginine, and cystine) are evaluated for inhibition of aldol condensation and dissolution of product in alkaline media. Inhibition efficiency of amino acids were studied at varied mole ratios of acetaldehyde to antipolymerant (2, 5, and 10), reaction temperature, and caustic concentration as a function of time (0.25, 1.0, 2.0 and 24.0 h) using UV spectrophotometry. Results obtained have been compared with efficiency of known amine derivatives. Arginine showed better efficiency when compared with aspartic acid and cysteine. Furthermore, data indicate that presence of carboxylic group in addition to amine group facilitates inhibition as well as dissolution of aldol polymer in alkaline media, while compounds with amine group acts as inhibitor for aldol condensation only.
Keywords: Aldol condensation; Inhibition; Dissolution; UV spectroscopy; FTIR
TPO/TPD study on the activation of silica supported cobalt catalyst by Hamid Al-Megren; Haoyi Chen; Yu Huang; Mohammad AlKinany; Peter P. Edwards; Tiancun Xiao; Yibo Wang (25-34).
Silica supported cobalt catalysts have been prepared using urea containing cobalt nitrate solution impregnation method, which can give high loading Co3O4 with relatively smaller crystallite size. Compared to the conventional impregnation method, the catalyst prepared with urea added to the cobalt nitrate solution provides higher activity for CO conversion and C5+ selectivity. To optimize the catalyst activation and simulate the industrial activation, TPO–TPR cycle treatment with or without steam has been applied to the prepared catalysts under various conditions. It is shown that reduction of pure hydrogen with high flow rate leads to a sharp temperature rise in the catalyst bed, which results in the sintering of the cobalt particles. A slow temperature rise with dilute hydrogen helps stabilize the cobalt particles, and the cycle treatment of the catalyst using TPO–TPR without steam induction has little effect on the size of cobalt particles. When steam is included in the reduction stream with hydrogen the TPR–TPO cycle treatment can help increase the Co dispersion, which increases the catalyst activity and selectivity to C5+.
Keywords: Supported cobalt catalyst; Fischer tropsch synthesis; Urea combustion; TPR-TPO
Propan-2-ol conversion to diisopropyl ether over (NH4) x X y PMo12O40 salts with X = Sn, Sb, and Bi. The effect of salt preparation pH by F. Chami; L. Dermeche; A. Saadi; C. Rabia (35-45).
(NH4)3PMo12O40 and (NH4) x X y PMo12O40 mixed salts (X: Sn, Sb and Bi) were prepared at pH 4 and characterised by IR, Raman and UV–Vis spectroscopies, 31P NMR, XRD, BET and thermal analysis (TG and DTA). The different salts were tested in propan-2-ol decomposition at 100 °C, after pretreatment in situ under nitrogen stream in 150–250 °C temperature range. Their properties were compared with those of (NH4)3PMo12O40, prepared at pH 1. The salts are active and the distribution of reaction products (propene, diisopropyl ether (DIPE) and acetone) depends both on the operating conditions and the catalyst composition. Propene selectivity increases from ca. 23 to ca. 95 % with the pretreatment temperature for all catalysts. The comparison of catalytic behaviour of salts for a pretreatment temperature of 200 °C shows that they are selective towards DIPE and that among them, SbPMo12 is the most selective one (ca. 72 %). The acetone, a dehydrogenation product, is mainly observed for salts prepared at pH 4, when the pretreatment temperature is low (150 °C) with selectivities of ca. 32–65 %.
Keywords: Keggin anions; Propan-2-ol; Diisopropyl ether; Dehydration; Oxygenated additives
Neural network modeling the effect of oxygenate additives on the performance of Pt–Sn/γ-Al2O3 catalyst in propane dehydrogenation by Younes Amini; Moslem Fattahi; Farhad Khorasheh; Saeed Sahebdelfar (47-54).
The effect of oxygenate additives, water and methanol, to the feed on the performance of industrial Pt–Sn/γ-Al2O3 catalyst in dehydrogenation of propane was studied by neural network modeling. Because of the complex nature of the system and very low levels of oxygenate addition, neural networks were employed as an efficient and accurate tool to obtain the behavior of the system. Dehydrogenation reaction was carried out in a fixed-bed quartz reactor in the temperature range of 575–620 °C. Steady state modeling was performed in three different levels of oxygenate addition, and conversion and selectivity at different levels. The optimum amounts of water and methanol for reaction temperatures of 575, 600 and 620 °C were found to be 83.60, 125.40 and 139.34 ppm, respectively, for water and 9.98, 24.94 and 49.88 ppm for methanol by neural network method. The neural network-based optimum was compared with that obtained from experimental data. In this case, various architectures have been checked using 70 % of experimental data for training of artificial neural network (ANN). Among the various architectures multi layer perceptron network with trainlm training algorithm was found as the best architecture. Temperature and water or methanol amount for the present constituents in the feed were network input data. Output data were conversion, selectivity to propylene and yield of propylene. Comparing the obtained ANN model results with 30 % of unseen data confirms ANN excellent estimation performance. The influence of different operating conditions on the accuracy of the results was also investigated and discussed. The propylene yields, however, passed a maximum at the optimum levels of oxygenates coincided with a substantial reduction of coke formation as well. The modeling results were accurate with <0.9 % error.
Keywords: Propane dehydrogenation; Pt–Sn/γ-Al2O3Oxygenates; Catalyst modifiers; Coke formation; Artificial neural network
Microwave-assisted conversion of ethane to ethylene by Siauw Ng; Craig Fairbridge; Sateesh Mutyala; Yan Liu; Jacqueline M. R. Bélanger; J. R. Jocelyn Paré (55-61).
A novel microwave reactor has been constructed for the conversion of ethane to ethylene. The bench-top, pilot-scale facility is capable of conventional furnace heating and microwave-assisted heating, thus allowing direct comparative studies between the conventional industry-wide process and the novel microwave-assisted conversion process. The latter makes use of chemical substances called susceptors that are good microwave absorbers and can transfer heat energy to the surrounding environment. The ethane feed stream is thus heated to achieve thermal conversion to ethylene. Data validating the apparatus and preliminary data on the feasibility of conversion are presented.
Keywords: Ethylene production; Microwave-assisted petrochemistry; Ethane-to-ethylene conversion; Microwave susceptors