Dielsalder Reactions In Water

In this chapter we will focus our attention first on Diels-Alder reactions in aqueous solutions much to the surprise of many chemists, it has been found that Methods and Reagents for Green Chemistry An Introduction, Edited by Pietro Tundo, Alvise Perosa, and Fulvio Zecchini Copyright 2007 John Wiley & Sons, Inc. Diels-Alder reactions and other types of cycloadditions are often greatly accelerated in water compared to organic solvents. Also the preferred stereochemistry (i.e., endo exo ratio)...

How Do I Prepare Thee Let Me Count The Ways

So, the observations in the preceding section raised the obvious question Just how many ionic liquids are there For each cation series that we consider, a matrix of salts can be generated with the following common anions n Cl2 Al2Cl7 2 BF4 2 PF6 2 CF3SO3 2 CH3CO2 2 RCO2 2 COCl4 22 NiCl4 22 This therefore gives us 81 ionic liquids for each cation type (N.B. we only consider the even chain lengths, as Figure 5.6 shows us that there is no advantage to be gained in using the more expensive odd...

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CARBOHYDRATES AS RENEWABLE RAW MATERIALS A MAJOR CHALLENGE OF GREEN CHEMISTRY Institute of Organic Chemistry, Technische Universit t Darmstadt, Darmstadt, Germany A raw material as feedstock should be renewable rather than depleting wherever technically and economically practicable.1 Coal, oil, and natural gas, the fossil resources built up over eons, are not only our main energy suppliers but they are also raw materials for a large variety of man-made products ranging from gasoline and diesel...

Mechanism Of The Aqueous Rate Acceleration

Several factors have been invoked to explain the aqueous rate acceleration aggregation of the reactants leading to micellar catalysis, effects connected with the internal pressure of the solvent, polarity of the solvent, H-bonding interactions with the solvent, and hydrophobic interactions (D V < 0). The initial literature was rather controversial, and there was a strong need for a systematic study using physical-organic techniques. Several experiments gave evidence against homotactic or...

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Figure 6.22 Selective reduction of haloaromatic ketones in the multiphasic system using Pt C. Figure 6.23 Selective reduction of haloaromatic ketones in the multiphasic system using Pt C. Figure 6.23 Selective reduction of haloaromatic ketones in the multiphasic system using Pt C. known as dioxins). They can be generated by incineration processes, high-temperature transformation of organic compounds, and in some cases they are residues of the agrochemical sector (e.g., insecticides such as DDT,...

The Multiphasic System

The third liquid catalyst-philic phase was constituted in the majority of cases by Aliquat 336 tricapryl-methylammonium chloride, (C8H17)3N+CH3Cl A336 , a well-known phase-transfer agent that is liquid at room temperature, and that dissolves in toluene and in iso-octane (Figure 6.15a). The peculiarity here is that, when water (even a drop) is added to the A336 isooctane solution, three liquid phases separate out (Figure 6.15b). Figure 6.15 shows the triphasic system at rest in order to...

Green Chemistry Catalysis And Waste Minimization

Delft University of Technology, Delft, The Netherlands A growing environmental awareness and increasingly stringent environmental legislation have focused the attention of chemical manufacturers on what has become known as sustainable development or green chemistry. A working definition of green chemistry is Technologies that efficiently utilize energy and (preferably renewable) raw materials and reduce, or preferably, eliminate, the generation of waste and avoid the use of toxic and or...

The Fourcomponent Reaction And Other Multicomponent Reactions Of The Isocyanides

Epoxy Resin Reaction With Ionic Liquids

Institute of Organic Chemistry and Biochemistry, Technische Universit t M nchen, Germany The usual syntheses of products from three or more educts require several preparative processes, and its intermediate or final product must be isolated and purified after each reaction. As the number of steps increase, the amounts of solvents and the preparative work grows, while the yields of products decrease and more and more solvents and by-products must be removed. In such reactions, scarcely all...

Adv Carbohyd Chem 1956 Publisher Beelik

Green Chemistry Theory and Practice, Oxford Univ. Press, Oxford, 1998, pp. 30-48. 2. Okkerse, C. van Bekkum, H. From fossil to green, Green Chem., 1999, 107-114. 3. National Research Council, USA, Priorities for Research and Commercialization of Biobased Industrial Products, Natl. Acad. Sci. Press, Washington, DC, 2000. 4. U.S. Department of Energy (DOE) (a) Vision for Bioenergy & Biobased Products in The United States, October 2002 Web.pdf. (b) Roadmap for...

Nonfood Valorization of Sucrose

Sucrose, affectionately called the royal carbohydrate,29 is a nonreducing dis-accharide, because its component sugars, d-glucose and d-fructose, are glycosidi-cally linked through their anomeric carbon atoms. Hence, it constitutes a b-d-fructofuranosyl a-d-glucopyranoside (Figure 2.7). It is widely distributed throughout the plant kingdom, is the main carbohydrate reserve and energy source, and an indispensable dietary material for humans. For centuries, sucrose has been the world's most...

Ionic Liquids For Green Chemistry

Room-temperature ionic liquids have been developed over the past decade as green solvents for industrial applications, ' ranging from the petrochemical industry, via heavy chemicals, fine chemicals, agrochemicals, and pharmaceuti- cals, to the nuclear industry, solar cells, and electrochemistry. ' Recent inde- pendent reports, , ' and many reviews, , 9 have highlighted ionic liquids as representing a state-of-the-art, innovative approach to green chemistry, and they are even suitable media for...

Ionic Liquid Applications

Reactor Solvent

There now is a proven extensive organic chemistry in ionic liquids, of which a few key reactions are listed below 21,26,28 Oxidation (with air and or dioxygen) N-Alkylation and O-alkylation It is clear that there are few restrictions to the possible reactions that can be studied. Of particular interest is an article demonstrating that the nature of the ionic liquid can dramatically influence the outcome of a reaction.69 In a study of the reactions between toluene and nitric acid, three...

Isobutane 2butene

Very strong Strong Medium-weak C5-C7 TMPs DHMs C C9 Figure 13.5 The influence of acid strength on the nature of the reaction products during the isobutane 2-butene alkylation. TABLE 13.2 Isobutane Alkylation Catalyzed by Beta Zeolite and Sulfated Zirconia at Different Reaction Temperatures A clear example of the possible use of acid and or superacid solids as catalysts is the alkylation of isobutane with butenes. Isobutane alkylation with low-molecular-weight olefins is one of the most...

Biocatalysis For Industrial Green Chemistry

Zhi Li, Martin Held, Sven Panke, Andrew Schmid, Renata Mathys, and Bernard Witholt Eidgen ssische Technische Hochschule Z rich, Switzerland Biocatalysis can make an important contribution to green chemistry due to several distinctive features, such as mild reaction conditions, nontoxicity, high chemo-, regio-, and stereoselectivity, and high turnover frequency. The potential of biocatalysis for the synthesis of chemicals is evident1-3 and examples of several industrial processes that are...

Methyl Methacrylate Process

THE OXIDATION OF ISOBUTANE TO METHACRYLIC ACID AN ALTERNATIVE TECHNOLOGY FOR MMA PRODUCTION Nicola Ballarini, Fabrizio Cavani, H l ne Degrand, Eric ti nne, Anne Pigamo, and Ferruccio Trifiro Dipartimento di Chimica Industr ale e dei Materiali, Universita di Bologna, Bologna, Italy 14.1 THE TECHNOLOGIES FOR METHYLMETHACRYLATE PRODUCTION Polymethylmethacrylate production currently amounts to more than 2.8 million tons per year on a worldwide scale, and the average yearly demand has been steadily...