Solvents

One of the key components of any green industrial process has to be the selection of the solvent, since working with conventional solvents results in the emission of volatile organic compounds (VOCs), a major source of environmental pollution (see Figure 5.4).8,9 There are fourt principal strategies to avoid conventional organic solvents 10,11 1. No solvent (heterogeneous catalysis) The first of these, the solventless option, is the best established,12 and is central to the petrochemical...

Biocatalyst Formulation And Tuning

To facilitate its application in organic synthesis, we developed a lyophilized cell powder of Sphingomonas sp. HXN-200 as a biohydroxylation catalyst.29 Hydro-xylation of N-benzyl-piperidine with such catalyst powder showed 85 of the activity of a similar hydroxylation with frozen thawed cells, shown in Figure 15.6. The fact that rehydrated lyophilized cells are able to carry out such a reduced nicotinamide adenine dinucleotide NADH -dependent hydroxylation indicates that these cells are...

Micellar Catalysis

Micellar catalysis, conducted in the absence of Lewis acid tends to inhibit the Diels-Alder reaction, relative to the reaction in water. The reason is that the local reaction medium in the Stern region is less favorable than bulk water. However, by combining Lewis-acid and micellar catalysis, enzyme-like rate accelerations can be obtained Table 7.5 in case the Lewis acid acts as the counterion for the micelle.14 Figure 7.9 Mechanistic interpretation for catalysis by Lewis acids containing...

Info

A. van Zorge, ESPR-Environ. Sci. Pollut. Res., 1995. Value represents total of incineration of sewage 5 and paper sludge 2 . fcValue represents lubrication oil. cRange represents total of secondary copper smelting 74-740 and secondary lead smelting 0.7-3.5 . Value represents diesel only. eRange represents total of industrial 100-1000 and residential wood burning 13-63 . PCDD F are formed and emitted from various thermal processes, such as municipal and hazardous...

Epoxidation Of Alkenes Other Than Allylic Alcohols

Methylstyrene Structure

The asymmetric epoxidation of unfunctionalised alkenes has received major attention and delivered considerable success through the development of metal-catalyzed oxo-transfer processes and the use of chiral manganese III salen com-plexes.4 The latter process requires the incorporation of a dissymmetric diimine bridge derived from a C2-symmetric 1,2-diamine and bulky substituents adjacent to the phenolate group. This is illustrated in the oxidation of cs-b-methylstyrene Figure 11.3 .5 The...

Multiphasic Systems

A multiphasic system for a chemical reaction can be constituted by any combination of gaseous, liquid, and solid phases. If a catalyst is present, it can be homogeneous or heterogeneous, thereby adding further phases and degrees of freedom to the system. Extra phases add new variables to a reaction, and it is therefore necessary that this be done for an advantage, such as an easier separation of the products, improved rates and selectivity, improved catalyst stability, Methods and Reagents for...

Isobutane Alkylation

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 important refining process for the production of high-octane number RON and MON , low red vapor pressure RVP gasoline.32 Currently, the reaction is carried out using H2SO4 or HF Table 13.1 , although several catalytic systems have been studied in the last few Adequate acid characteristics of solids...

The Role Of Catalysis

The increasing use of catalytic processes can substantially reduce waste at the source, resulting in primary pollution prevention. The theoretical process efficiency 3 PhCH OH CH3 2 Cr03 3 H2S04 -- 3 PhCOCH3 Cr2 S04 3 6 HzO Atom efficiency 360 860 42 E ca. 1.5 PhCH OH CH3 1 2 02 - PhCOCH3 H20 Figure 9.1 Acetophenone synthesis by stoichiometric and catalytic oxidation. can be quantified by the atom efficiency, the ratio between the molecular weight of the product, and the sum of the molecular...

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 they are...

Synthesis Of Catechols By A Recombinant Whole Cell Biocatalyst

Amberlite Xad Wastewater

An interesting example of the application of recombinant whole-cell biocatalysis is the conversion of 2-hydroxybiphenyl 2-phenylphenol to 2,3-dihydroxybiphenyl 2-Hydroxybiphenyl 3-monooxygenase E.c. 1.14.13.44 Figure 15.7 Production of 3-substituted catechols using a designer biocatalyst. or 3-phenylcatechol Figure 15.7 . Catechols are important building blocks for the chemical and pharmaceutical industries. However, their chemical synthesis is cumbersome. Especially the synthesis of...

Benzylic Hydroxylation

Direct C-H oxidation is very difficult but extremely important, as it occurs in some important biological processes.20 The presence of some kind of activating group such as an aryl or alkenyl group offers some encouragement for success. Benzylic hydroxylation can be effected using iodosylbenzene and an iron oxo species derived from a porphyrin Figure 11.10 .21 Such reactions mirror the role of cytochrome P-450 in monooxygenase enzyme processes. The yields obtained for benzylic hydroxylation are...

Synthesis Of Epoxystyrene With Very High Enantioselectivity

Another useful bioconversion is the epoxidation of styrene to epoxystyrene. Styrene oxide is a valuable building block, because the epoxide function allows versatile synthetic chemistry, and the benzene ring is part of the majority of today's drugs Figure 15.10 . It is used, for example, in the production of the anti-helmintic drug Levamisole.42 However, to be an attractive building block for drug synthesis, the styrene oxide needs to be enantiopure. There are some chemical asymmetric synthesis...

M. T. Reetz J.g. De Vries Chem. Commun. 2004 14 1559-1563

Halpern, Phase-Transfer Catalysis Fundamentals, Applications and Industrial Perspectives, Chapman amp Hall, New York, 1994. 2. E. V. Dehmlow, S. S. Dehmlow, Phase-Transfer Catalysis, 3rd ed., Verlag Chemie, Weinheim, 1993. 3. B. Cornils, W. A. Herrmann, I. T. Horvath, et al., Eds. Multiphase Homogeneous Catalysis Wiley-VCH, Weinheim, 2005. 4. A. K. Bose, S. Pednekar, S. N. Ganguly, et al., Tetrahedron Lett., 2004, 45, 83518353. 5. K. Tanaka, Solvent Free Organic...

Ionic Liquid Applications

Matthias Maase

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 completely...

The Modern Chemistry Of The Isocyanides

A new era of the isocyanide chemistry began in 1958 when the isocyanides became generally available by dehydrating the corresponding formylamines in the presence of suitable bases Scheme 1.3 .4 A systematic search for the most suitable dehydrating reagent revealed early on that phosgene31 is excellent for this purpose. Later, when phosgene transportation was not allowed anymore, it was locally produced from triphosgene.32 Also diphosgene33 and phosphorus oxychlor-ide,4 can be used, particularly...

Likely Costs Of Large Scale Hydroxylation Or Epoxidation Processes With Whole Cell Biocatalysts

To get some idea of the prices to be expected for compounds produced with these approaches, we have estimated the total cost of producing 10,000 tons per annum of 1-octanol from -octane, based on data collected for this conversion by P. oleovorans, during growth in a two-liquid-phase system containing 15 v v hexadecane as a carrier phase.47 n-Octane is dissolved in the carrier phase to a concentration of 5 -10 v v , converted by the P. oleovorans cells in the aqueous phase, and the product...

Alkane Isomerization

Traditionally, the isomerization of light alkanes n-C5 and n-C6, light straight run gasoline have been carried out using bifunctional systems, that is, Pt-AlCl3 Al2O3 UOP, BP or Pt-Mordenite Shell, Mobil, Norton, Su-Oil, IFP catalyst.17,18 A clori-nated alumina-based catalyst act at a low operation temperature that is favorable in equilibrium.17 This allow as to obtain isomerates of about 83 RON. However, it has the disadvantages of being highly sensitivity to water in the feed requiring the...

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 lt 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...

Factors And Atom Efficiency

Two useful measures of the potential environmental impact of chemical processes are the E-factor,5-7 defined as the mass ratio of waste to desired product, and the Methods and Reagents for Green Chemistry An Introduction, Edited by Pietro Tundo, Alvise Perosa, and Fulvio Zecchini Copyright 2007 John Wiley amp Sons, Inc. TABLE 9.1 E-factors for Different Segments of the Chemical Industry TABLE 9.1 E-factors for Different Segments of the Chemical Industry atom efficiency,1'2 calculated by...

Photochemical Reactions

Chemical reactions from the excited state are not the only and not necessarily the most important way in which a reaction can be initiated by light absorption. A completely different approach involves the generation of some activated, but ground state, intermediate through the photochemical step, thus leading to a photoinitiated reaction, even if some of the chemical steps are actually thermal reactions. The first group, perhaps scientifically trivial, but quite useful in the laboratory and...

Lewisacid Catalysis In Water

Lewis-acid catalysis of Diels-Alder reactions Figure 7.5 in organic solvents leads to an enhancement of the reaction rate, because of the lowering in energy for the lowest unoccupied molecular orbital LUMO of the dienophile, and an improvement in the selectivity with specific ligands. Experiments aimed at examining the possibility of catalyzing Diels-Alder reaction in water gave rise to interesting results. For the reaction of bidentate die-nophiles 1 with cyclopentadiene,11 shown in Figure...

Anastas P.t. And Williamson T.c. 1996 . Green Chemistry An Overview. In Green Chemistry Designing Chemistry For The

StC. et al. Pure Appl. Chem., 2000, 72, 1207 b Green Chemistry, Theory and Practice, Anastas, P. T. Warner, J. C. Eds. , Oxford University Press, Oxford, 1998. 2. Sheldon, R. A. Pure Appl. Chem., 2000, 72, 1233-1246. 3. Trost, B. M. Science, 1991, 254, 1471-1477. 4. Anastas, P. T. Williamson, T. in Green Chemistry Designing Chemistry for the Environment, Anastas, P. T. Williamson, T. Eds. ACS Symposium Series, No. 626, American Chemical Society, Washington...

Sphingomonas Sp. Hxn-200

Figure 15.2 Improvement of the hydroxylation activity and enantioselectivity with Sphingomonas sp. HXN-200 by substrate modification. hydroxylation with Sphingomonas sp. HXN-200 gave 62 of S -enantiomer in 53 ee with six times higher activity. It was found that Sphingomonas sp. HXN-200 contains a soluble alkane mono-oxygenase and accepts a broader range of substrates. The enantioselectivity and activity were further improved by introducing a docking protecting group into the pyrrolidine...

The Technology Challenges

Cellobiose Einheit

This section reviews the challenges faced by the exploitation of CO2, stranded methane, and biomass residues in an attempt to highlight areas where technology breakthroughs and research efforts are needed. Phosgene is commercially obtained by passing carbon monoxide and chlorine over activated carbon.3 Around 7 million tons of phosgene are produced worldwide, 85 of which is utilized in the production of isocyanates for polyurethanes, 10 in the production of aromatic polycarbonate, and 5 in fine...

Synthesis Of Catechols

Figure 15.9 Synthesis and in situ recovery of 3-phenylcatechol. Figure 15.9 Synthesis and in situ recovery of 3-phenylcatechol. of 80 to 90 , and after desorption and isolation of product, overall yields of 60 to 80 were estimated.41 The entire process was scaled up to the 300 L scale, resulting in the formation of a total of 1.1 kg 3-phenylcatechol, at a purity of 77 . One crystallization was sufficient to bring 25 g of the material to a purity of gt 98 this compound is now for sale by Fluka,...

Catayst Adsorption To Minimise Global Warming

Hfau Zeolites

This A cracking was shown to be 20 times faster than the rearrangement of type B involved in n-alkane hydroisomerization. As a consequence, over ideal bifunctional Pt HFAU catalysts, that is, over catalysts on which acid isomerization and cracking of alkene intermediates are the limiting steps, the maximum yield of isodecanes that could be obtained is not very high 50 .16 The maximum yield is even lower 20 with HMFI as the acidic component of the bifunctional catalyst this can be ascribed to...

4-methoxy Acetophenone With Zeolite Process

Mcm Structure

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...

Dielsalder Reactions In Water

Diels Alder Problem Sets

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 amp 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 of...

The Multiphasic System

Phase Transfer Catalyst

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 visualize the...

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...

Batch Methylation Reactions with DMC

Under batch conditions, methylations with DMC must necessarily be run in sealed autoclaves, given its boiling point 90 C and the reaction temperature gt 160 C . Batch methylations with DMC can be performed on a number of different substrates and, under such conditions, the reaction mechanism can be conveniently investigated in fact, the sampling of the reaction mixture at different conversions, and the identification of possible intermediates see later is easier with respect to CF-processes....

Catalysis In Water

Another environmental issue is the use of organic solvents. The use of chlorinated hydrocarbons, for example, has been severely curtailed. In fact, so many of the solvents favored by organic chemists are now on the black list that the whole question of solvents requires rethinking. The best solvent is no solvent, and if a solvent diluent is needed, then water has a lot to recommend it. This provides a golden opportunity for biocatalysis, since the replacement of classic chemical methods in...

Main Zeolites Features

12.1.1 Description and Denomination of Zeolites Zeolites are crystalline aluminosilicates based on a three-dimensional arrangement of TO4 tetrahedra SiO4 or AlO4 connected through their O atoms to form sub-units and then large lattices by repeating identical building blocks unit cells, u.c. . The structure formula of zeolites i.e., the u.c. composition is the following Mx n AlO2 x SiO2 y, where n is the valence of M cation or proton , x y the number of tetrahedra per u.c., and y x the atomic Si...

Acid And Superacid Solid Materials As Noncontaminant Alternative Catalysts In Refining

Heteropolyacids

Intituto Tecnolog a Qu mica, UPV-CSIC, Valencia, Spain New and pending industrial legislation throughout the world requires more stringent environmental protection. Thus, it will soon become illegal to release into the atmosphere some products benzene, volatile hydrocarbons, carbon oxides, corrosive and reactive oxides of sulfur, and nitrogen that contribute to the greenhouse effect. Due to new environmental legislation, many refiners will be required to make significant processing changes. In...

The Technologies For Methylmethacrylate Production

H3c Ch3 Chemical Compound

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 increasing in recent years by more than 0.2 million tons. In contrast to the majority of bulk chemicals, for which the number of competitive processes is limited to one or two technologies, in the case of methylmethacrylate MMA , the monomer for polymethylmethacrylate production, there are several different technologies that are...

Supported Liquid Phase

H3co Picture

Research in this field started in the wake of the reports of SL-PC. Consisting of a catalyst-containing supported liquid layer for CF reactions in the gas phase, the concept was transferred to batch reactions, using a catalyst dissolved in a supported aqueous phase. This was first referred to as supported aqueous-phase catalysis SAPC by Davis in an article published in Nature in 1989.8 Later, the concept was extended, using a variety of names, but the essence has remained the same a supported...

Screening For The Regio And Stereospecific Hydroxylation Of Pyrrolidine

H3c Ch3 Ch3 Ch3 Ch3

We were interested in the discovery and development of biocatalysts for the regio- and stereoselective hydroxylation of pyrrolidine to 3-hydroxypyrrolidine, since both S - and R -3-hydroxypyrrolidines are useful intermediates for the preparation of several pharmaceuticals Figure 15.1 , and they are difficult to prepare by chemical syntheses. To avoid random screening of a large number of microorganisms, we concentrated on microorganisms with selected biodegradation abilities. Microorganisms...

Potential Industrial Chemicals from DXylose

D-Xylose, also referred to as wood sugar because it is, in the form of its polysaccharide xylan, widely distributed in woods, straw, and other fibrous tissues, usually in close association with cellulose. Acid hydrolysis of such xylans in agricultural wastes corn cobs,99 cottonseed bulks, or other woody materials split their b l 4 -glycosidic linkages to d-xylose Scheme 2.13 . When more forcing acidic conditions are applied, furfural is the product due to dehydratizations cf. see earlier in...

Epoxidation Of Enones

Metal alkyl peroxides can be used for the epoxidation of electron-deficient alkenes such as enones.12 The use of a combination of diethylzinc, oxygen, and N-methylephedrine gave epoxides in very high yield and generally high enantio-selectivity Figure 11.8 .13 Figure 11.8 Epoxidation of enones by metal hydroperoxides. 11.4 DIHYDROXYLATION OF ALKENES Asymmetric dihydroxylation can be achieved using osmium tetroxide in conjunction with a chiral nitrogen ligand.14 The very successful Sharpless...

Green Chemistry Circular Economy Global Warming

The Summer School on Green Chemistry was founded in 1998, in the wake of the growing interest in green chemistry among the chemical community. For the first time it was being recognized by chemists that there could be and had to be mutual understanding and collaboration between A the players involved in chemical production, and B representatives from all the social categories concerned with safeguarding the environment and human health. It appeared clear that the existing gap could be bridged...

Conclusion

We can now complete the picture and easily visualize a possible long-term future for feedstock and processes, as shown in Figure 10.15. The occurrence of this vision, however, is strongly dependant on the ability of researchers to remove the technological barriers highlighted in the previous section. Renewable resources based 85 r.ZTN x Renewable resources based 85 r.ZTN x Broad variety of commodity and differentiated chemicals and plastics Figure 10.15 Emerging future Duality in feedstocks and...

Heterocycles 2001 54 1 131-138

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 amp Biobased Products in The United States, October 2002 Web.pdf. b Roadmap for Biomass...

Current Nonfood Industrial Uses Of Sugars

Organic Pt02 Catalyst

The current utilization of carbohydrates as a feedstock for the chemical industry be it for bulk, commodity, intermediate, fine, or high-value-added speciality chemicals is modest when considering their ready availability at low cost and the huge as yet unexploited potential. The examples currently realized on an industrial scale are outlined briefly. With production of about 24 million tons 300 million hectoliters hL 12 , fermentation ethanol bioethanol is the largest volume biobased chemical...

Green Chemistry References

The White House, 2005 whitehouse.gov news releases 2005 05 20050518-4.html 2. Moore, M. Stupid White Men, Penguin, London, 2002. 3. BBC, BBC News Online, 2005 4. United Nations Framework Convention on Climate Change, Kyoto Protocol, 1997 http unfccc.int resource docs convkp kpeng.html 5. U.S. Environmental Protection Agency, Global Warming Climate, 2000 http yose-mite.epa.gov oar globalwarming.nsf content climate.html 6. U.S. Environmental Protection Agency, The Potential Effects...

The Unions Of The Ucr And Further Reactions

Already in the early days of the U-4CR, several types of 5CRs were found.3,72 It was also observed long ago that an autoxydizing 6-component reaction of two iso-cyanides took place besides the main U-4CR,73 and the structure of one of these by-products was determined by an X-ray measurement.74 The reaction mechanism of such autoxydation was determined75 by the assistance of the computer program RAIN.76 At that time it was not yet known that the MCRs of isocyanides with more than four educts...