Upgrading Chemistry

It is well established that upgrading and refining of different feedstocks is related to their chemical properties. Since petroleum is composed of complex hydrocarbon mixtures, it is impossible to identify each individual component and its upgrading chemistry. Most investigations, to date, relate the thermal or catalytic behavior of petroleum feedstocks to their fractional composition. The hydrocarbon components of petroleum fall into three classes ... 

Reaction of Feedstock Components - Simplification of Upgrading Chemistry... 

Rahimi, P.M. Dettman, H.D. Dawson, W.H. Nowlan, V. Del Bianco, A. Chomet, E. Coke fonnation from asphaltenes - solvent and concentration effects, CONRAD workshop on bitumen upgrading chemistry, June 7-8,1995, Calgary, Alberta. 

Rahuni, P. Dettman, H. Gentzis, T. Chung, K. Nowlan, V. Upgrading chemistry of Athabasca bitumen fractions derived by super critical fluid extraction. Presented at the 47 CSChE conference, Edmonton, Alberta, Canada, October 5-8,1997. 

As the world s supplies of light crude oils dwindle, processes for refining heavy oils and bitumen are becoming increasingly important. Chapter 19 deals with heavy oil processing. It reviews the chemical composition, physical and chemical properties, and upgrading chemistry of bitumen and heavy oils. 

Another favorable aspect of these polymers is their conformity with the principles of green chemistry. The latter sets guidehnes for the chemical industry in order to secure sustainable development, while increasing process economy [3,4]. Briefly, green chemistry, and the related green engineering [5] call for an increase in, and/or upgrading of ... 

At the low-molecular-weight end of the spectrum, a process newly commercialized by Mobil for converting methanol into gasoline has significantly expanded opportunities in C-1 chemistry— the upgrading of one-carbon molectrles to mrrlticarbon products. The process involves the use of ZSM-5, a shape-selective zeolite catalyst. (See "Zeolite and Shape-Selective Catalysts" in Chapter 9.)... 

Models of chemical reactions of trace pollutants in groundwater must be based on experimental analysis of the kinetics of possible pollutant interactions with earth materials, much the same as smog chamber studies considered atmospheric photochemistry. Fundamental research could determine the surface chemistry of soil components and processes such as adsorption and desorption, pore diffusion, and biodegradation of contaminants. Hydrodynamic pollutant transport models should be upgraded to take into account chemical reactions at surfaces. 

Industrial Engineering Chemistry Research 36, No. 11, Nov. 1997, p.4436-44 ULTRAPYROLYTIC UPGRADING OF PLASTIC WASTES AND PLASTICS/HEAVY OIL MIXTURES TO VALUABLE LIGHT GAS PRODUCTS... 

IRCELYON, Institut de recherches sur la catalyse et I environnement de Lyon, UMR 5256 - CNRS - Universite de Lyon Bioresources upgrading and green chemistry, 2 avenue Albert Einstein 69626 Villeurbanne Cedex, France... 

With a common intermediate from the Medicinal Chemistry synthesis now in hand in enantiomerically upgraded form, optimization of the conversion to the amine was addressed, with particular emphasis on safety evaluation of the azide displacement step (Scheme 9.7). Hence, alcohol 6 was reacted with methanesul-fonyl chloride in the presence of triethylamine to afford a 95% yield of the desired mesylate as an oil. Displacement of the mesylate using sodium azide in DMF afforded azide 7 in around 85% assay yield. However, a major by-product of the reaction was found to be alkene 17, formed from an elimination pathway with concomitant formation of the hazardous hydrazoic acid. To evaluate this potential safety hazard for process scale-up, online FTIR was used to monitor the presence of hydrazoic acid in the head-space, confirming that this was indeed formed during the reaction [7]. It was also observed that the amount of hydrazoic acid in the headspace could be completely suppressed by the addition of an organic base such as diisopropylethylamine to the reaction, with the use of inorganic bases such as... 

Evaluation of the above route against our initial target objectives for the synthesis of taranabant indicated a high level of success, not just for the primary objectives of removing the tin chemistry and chiral chromatography, but for a number of other process improvements (Table 9.2). Of particular note was that the three crystalline intermediates were key for purification, first the phenethylamine salt 12 for the classical resolution, secondly the HC1 salt of amine 2 allowed for upgrade of diastereomeric purity, and finally the API allowed for upgrade of enantiomeric purity via initial removal of racemic material. 

Vallet-Regi, M. and Arcos D. (2005) Silicon substituted hydroxyapatites. A method to upgrade calcium phosphate based implants. Journal of Materials Chemistry, 15, 1509—1516. 

Caballero, M. A. Aznar, M. P. Gil, J. Martin, J. A. Frances, E. Corella, J., Commercial steam reforming catalysts to improve biomass gasification with steam-oxygen mixtures. 1. Hot gas upgrading by the catalytic reactor. Industrial and Engineering Chemistry Research 1997,36(12), 5227-5239. 

Pyrolysis has a long history in the upgrading of biomass. The dry distillation of hardwood was applied in the early 1990s to produce organic intermediates (methanol and acetic acid), charcoal and fuel gas [3]. Today s processes can be tuned to form char, oil and/or gas, all depending on the temperature and reaction time, from 300 °C and hours, to 400-500 °C and seconds-minutes, to >700 °C and a fraction of a second [3, 19, 23, 24], The process is typically carried out under inert atmosphere. We illustrate the basic chemistry of pyrolysis by focusing on the conversion of the carbohydrate components (Fig. 2.4). The reaction of the lignin will not be covered here but should obviously be considered in a real process. Interested readers could consult the literature, e.g., [25]. Pyrolysis is discussed in more details elsewhere in this book [26],... 

Desulphurisation of hydrocarbon fuels has traditionally been carried out primarily as part of the refining and upgrading process. Accordingly by far the most advanced and best understood chemistry and technology is to be found in this area. Prior to the advent of major concern for environmental impact of fossil fuel combustion products relatively little was done to desulphurise hydrocarbon fuels (principally coal) prior to combustion and past effects of large scale consumption of high sulphur coals can still be seen in major industrialised areas around the world. 

The director of this Institute, Dr. Herbert Kolbel, Professor of Technical Chemistry, has been involved during the second World War II in the development of upgrading coal to other hydrocarbons according to the Fischer-Tropsch synthesis in bubble column reactors with suspended catalysts. He was interested in gaining more knowledge s on of transport processes and chemical reactions in these reactors. 

With the (S)-PGA enamine-amide route, sitagliptin was prepared in 65% overall yield from 2,4,5-trifluorophenylacetic acid (9) in 4 chemical steps [18]. Two addi-honal crystallization steps are required for enanhomeric purity upgrade and final salt formation. The (S)-PGA enamine-amide hydrogenahon approach eliminated the ester hydrolysis and amide formation steps of the (S)-PGA enamine-ester route by incorporating the newly developed Meldrum s acid chemistry, which enabled direct amidahon with triazole 3. 

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