A study was undertaken in order to understand the kinetics and mechanism of the chemical oxidation of N, N-diethyl-m-toluamide, an insect repellent, by sulfate radical. In this experiment, sulfate radical was generated using peroxymonosulfate with iron (II) and cobalt (II) as activator. The second-order rate constant for the reaction of the sulfate radical with N, N-diethyl-m-toluamide was found to be (1.9±0.1) × 109 M-1 s-1 at pH 7 and a temperature of 25oC. Experiments for the chemical oxidation of N, N-diethyl-m-toluamide in river water and secondary wastewater revealed that the percentage of the removal of N, N-diethyl-m-toluamide was slightly influenced by the water matrices. However, the selected oxidation systems are not effective for the removal of N, N-diethyl-m-toluamide in seawater. Transformation by-products of N, N-diethyl-m-toluamide generated using peroxymonosulfate/iron (II) sulfate, peroxymonosulfate/iron (II) chloride, peroxymonosulfate/cobalt (II) sulfate and peroxymonosulfate/cobalt (II) chloride systems were identified. The results indicated that there are slight differences in the distributions of the transformation by-products detected depending on the activator. The common transformation by-products detected in all selected oxidation systems are N, N-diethylbenzamide, N-ethyl-m-toluamide, N, N-dimethyl-m-toluamide, N-ethyl-N-acetyl-m-toluamide, 2-(diethylamino)-1-m-tolylethanone, monohydroxylated N-ethyl-m-toluamide, and dihydroxylated N, N-diethyl-m-toluamide. Monohydroxylated N, N-diethyl-m-toluamide were detected only when the peroxymonosulfate/iron (II) system was applied. For the peroxymonosulfate/cobalt (II) systems, additional isomers of monohydroxylated N-ethyl-m-toluamide were detected. Peroxymonosulfate/cobalt (II) also transformed 2-(diethylamino)-1-m-tolylethanone into N-ethyl-N-(2-oxo-2-m-tolylethyl) acetamide and monohydroxylated 2-(ethyl(vinyl)amino)-1-m-tolylethanone as transformation by-products.

In this work, kinetics and thermodynamics of esterification reaction were studied. This research investigated the esterificationreaction between methanol and acidified oil catalyzed by sulfonated cation exchange resin and proposed a new rate equation forconsideration of kinetics of this reaction according to the Langmuir-Hinshelwood mechanism. Thermodynamics and kineticsparameters were calculated according to this equation. The results of this study showed that this new equation was a reasonableequation for kinetics study of the esterification reaction. Also, kinetics parameters were calculated for this reaction. Activationenergy and Arrhenius pre-exponential factor were equal to 75. 2477 􀝇 􀝆 /􀝉 􀝋 􀝈 and 8. 9994 􀵈 10􀬵 􀬷 􀜮 􀝅 􀝐 /􀝉 􀝋 􀝈 . 􀝄 respectively.

This work is carried out to investigate combustion characteristics of a dual fuel (diesel-gas) engine at part loads, using a quasi-dimensional multi zone combustion model (MZCM) for the combustion of diesel fuel and a single zone model with detailed chemical kinetics for the combustion of natural gas fuel. chemical kinetic mechanisms consist of 184 reactions with 50 species. This combustion model is able to establish the development of the combustion process with time and the associated important operating parameters, such as pressure, temperature and heat release rate (H.R.R). The dual-fuel engines, inevitably suffer from lower thermal efficiency, higher carbon monoxide and unburned hydrocarbon at part local conditions. Therefore this paper is an attempt to investigate the combustion phenomena at part loads and using methods such as injection timing advance, increasing pilot fuel quantity, and intake air throttling to improve the mentioned problems. It was found that the advancing of diesel injection timing gave little improvement in combustion parameters but other proposed methods promoted better combustion. Predicted values show good agreement with corresponding experimental values over a whole range of engine operating conditions. Implications will be discussed in details.

A new potassium persulfate redox system has been investigated for the graft polymerization of vinyl monomers. In this study potassium persulfate system was used for initiation the polymerization. Graft polymerization of acrylonitrile (AN) onto starch (Sta) was carried out in aqueous solution using potassium persulfate (I) redox system. It was found that the percentage of grafting and rate of grafting were all dependent to some extent, on the concentration of the I, AN, Sta and Sta/ water as well as reaction time and temperature. The kinetics of the graft polymerization of AN onto Sta in aqueous solution was studied by Kjeldahl method (quantity and qualitative determination nitrogen content), and the kinetics of AN homopolymerization in the same system was studied by bromometry titration (residue monomer determination). The following rate expression (rate of graft polymerization and rate of homopolymerization) Rg=k·[AN]1.185·[I]0.499·[Sta]0.497 and Rh=k·[AN]1.359·[I]0.436 were obtained and a suitable mechanism was suggested. The graft copolymer was investigated with an infrared spectroscope. The overall activation energy was found to be 56.95 kJ/mol within the temperature range of 40-65°C.