Aroh rocooch3 aroch3 roh c02

Scheme 4.23 Methylation of phenols with mixed organic carbonates (ROCO2CH3). As can be seen, asymmetrical carbonates give high chemoselective methylation reactions, provided that R has at least three carbon atoms (R > n-C3, entries 2-4). Yet, in the case of reactive benzyl or allyl termini, the O-alkylation (forming PhOR) competes significantly with the formation of anisoles (entries 5-6). Most satisfactory results can be obtained with the use of 2-(2-methoxyethoxy) ethyl carbonate...

Ccc

There are several means to maximize the yield in the desired monoalkylation product high aromatic alkylation agent ratio, association of a transalkylation unit to the alkylation unit, and use of a shape selective zeolite as catalyst. Figure 12.4 Ethylbenzene synthesis. Commercial processes. AlCl3 + HCl catalyst (1950) AlCl3 corrosivity and problems associated with safe handling and disposal. For one tonne of EB, consumption of 2-4 kg catalyst, 1 kg of HCl, and 5 kg of caustic solution with...

Continuous Flow Plug Flow and CSTR Reactors

Under GL-PTC conditions, a gaseous stream of reagent and DMC flows over a catalytic bed usually composed of a porous inorganic material (usually corundum in the form of a spherical extrudate of 1-3 mm of diameter), which acts as a support for both an inorganic base (an alkaline carbonate) and a phase-transfer (PT) agent such as phosphonium salts,13 crown ethers,14 and polyethylene glycols (PEGs). These latter in particular, although less efficient than other PT agents, are desirable because...

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...

Info

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...

Oh

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...

Zeolite Catalysts For Cleaner Technologies

University of Poitiers, Poitiers, France The name of zeolites, which originates from the Greek words zeo (to boil) and lithos (stone), was given some 250 years ago to a family of minerals (hydrated aluminosilicates) that exhibited intumescence when heated in a flame.1 However, the history of zeolites really began 60 years ago with the development of synthesis methods. Commercial applications in three main fields ion exchange, adsorption, and catalysis were rapidly developed, the corresponding...

[HOCH2CHROHu u

Scheme 4.4 Insertion of CO2 into epoxides and cleavage of cyclic carbonates. Step 1. Catalyst MgO, CaO. Step 2. Catalyst zeolites exchanged with alkali and or earth metal ions. Some of the toxicological properties of DMC and phosgene and DMS are compared in Table 4.1. TABLE 4.1 Comparison Between the Toxicological and Eco-Toxicological Properties of DMC, Phosgene, and DMS TABLE 4.1 Comparison Between the Toxicological and Eco-Toxicological Properties of DMC, Phosgene, and DMS Note NOEC...

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

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 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...

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...