Examples from Bayer

Example 7. Solvent-Borne, One-Component, Moisture-Cure, Aliphatic Polyurea Coating. This example is of a more traditional one-component coating formulation using a volatile solvent as a diluent. The active ingredient is a modified HDI, Desmodur N-75 BA from Bayer. 

Example 11. One-Component, Moisture-Cure Polyurethane Sealant. This example is of a low-hardness, high-elongation, moisture-curable polyurethane sealant. The material is based on a low-%NCO prepolymer made from 4,4 -MDI and a low-unsaturation (low-monol-content) Acclaim polyol from Bayer. It is adapted from (a) J. Lear et al., Adhesives Age, February 1999, pp. 18-23 and (b) B. Lawrey, et al., presented at UTECH 2000, The Hague, The Netherlands, March 30, 2000, Crain Communications London, 2000. 

The authors thank the companies BASF, BAYER, DEGUSSA, WACKER and the former HOECHST AG who made available to us revised and new examples from industrial laboratories. We also thank the Chemistry Editorial and Production Department of Springer-Verlag for an excellent cooperation. 

Much work has been done to develop catalyst systems that optimize yield and reduce side reactions. The reaction has an induction period, which depends on the temperature and the amount of catalyst.8 An early patent from Bayer claims that a nearly quantitative yield can be achieved in the conversion of l,2-dibromo-1-chloro-l.2.2-trifluoroethane(5) into 1,1-di-bromo-l-chloro-2,2.2-trifluoroethane (6) when aluminum tribromide is used in 2-broino-2-chloro-1,1,1-trifluoroethane (4) as solvent.12 A Japanese patent26 describes the activation of aluminum trichloride or alumina by pretreatinent with l,L2-trichloro-l,2,2-trifluoroethane (1) (see discussion of compound 19, vide infra). A later patent claims that aluminum trichloride and tribromide can also be activated by complexing with 1,1-dichloro- (CF3CFC12) and 1,1-dibromo-1,2,2,2-tetrafluoroethane (CF3CFBr2), respectively 2 an example of the latter is shown in the formation of bromofluoroalkane 10. 

The probably most striking example so far of solvent influence on enzyme selectivity has been found by Yoshihiko Hirose and co-workers at the Amano Corp. in Nagoya, Japan, studying nifedipines, which provide a befitting conclusion of this chapter and a transition to the next on use of enzyme catalysis in the pharma industry. Nifedipines, structurally 1-substituted dihydropyridine mono- or diesters, are used in cardiovascular therapy, where they are termed calcium antagonists (Goldmann, 1991) the most prominent representative is Adalat from Bayer (Leverkusen, Germany). While the simplest achiral dihydropyridines can be syn-... 

In practice, the Bayer process (Fig. 8.7), which has not yet been industrialized, starts with a steam-cracked C cut, for example, from which the butadiene and isobutene are extracted, and which therefore consists of about 20 per cent weight butanes and 80 per cent weight n-butenes. The butanes behave as a diluent The unit has three sections ... 

In a 250 ml plastic beaker 10 g of a strongly branched polyester with a high OH number of about 350-370 (see Example 4.1b or commercial sample, e.g., Desmophen 4070 X from Bayer AG) and 15 g of methylene di(phenylisocyanate) (technical product, liquid mixture of the diisocyanate with poly-MDl, e.g.. 

U.S. Pat. 4,444,933 (Apr. 24,1984), P. S. Columbus and J. Anderson (to Borden, Inc.). See, for example, Internet address www.pu.bayer.com/pu.cfm show=3000 for product literature from Bayer Corp. (www.pu.bayer.com) and Internet address www.basfde/en/dispersionen/products/industrial coating/polyisocyanates/ for product literature from BASF Corp. Many raw materials for urethane adhesives will be foimd in product literature for raw materials for coatings because of the relatively larger market size for urethane coatings. 

An example of a tissue-specific CA is the Gd + complex of ethoxy-benzyl (EOB)-DTPA. This lipophilic complex, known as Primovist (formerly Eovist , from Bayer Schering Pharma AG), enters the hepatocytes through the membrane-bound organic anion transporter and allows for the detection of hepatic lesions characterized by a decrease (metastases, hepatocellular carcinoma) or an increase (focal nodular hyperplasia) in the hepatocytes signal. This liver-specific CA is then eliminated via the biliary pathway and by the kidneys. ... 

The chemical properties of cycHc ketones also vary with ring size. Lower members (addition reactions, than corresponding acycHc ketones. The Cg—C 2 ketones are unreactive, reflecting the strain and high enol content of medium-sized ring systems. Lactones are prepared from cycHc ketones by the Bayer-ViUiger oxidation reaction with peracids. S-Caprolactone is manufactured from cyclohexane by this process ... 

A.lkaline Solutions. The most important example of alkaline leach is the digestion of hydrated alumina from bauxite by a sodium hydroxide solution at 160-170°C, ie, the Bayer process (see Aluminumand aluminum alloys). 

Example 2. Two-Shot Cast Elastomer (Prepolymer Method). Synthesis of polyurethane elastomers via the prepolymer method is challenging and requires especial attention to details and techniques. This example is a relatively easy one, using a low-viscosity, 9.6% NCO MDI-based poly(tetramethylene ether) glycol prepolymer. It is adapted from the Bayer Product Information Bulletin for Baytec ME-090 prepolymer. 

Examples for necessary process improvements through catalyst research are the development of one-step processes for a number of bulk products like acetaldehyde and acetic acid (from ethane), phenol (from benzene), acrolein (from propane), or allyl alcohol (from acrolein). For example, allyl alcohol, a chemical which is used in the production of plasticizers, flame resistors and fungicides, can be manufactured via gas-phase acetoxylation of propene in the Hoechst [1] or Bayer process [2], isomerization of propene oxide (BASF-Wyandotte), or by technologies involving the alkaline hydrolysis of allyl chloride (Dow and Shell) thereby producing stoichiometric amounts of unavoidable by-products. However, if there is a catalyst... 

Very recent relevant observations reveal that the TCS approach albeit certainly significant as conceptual and operational tool in the issue of metal nanoclusters size control, requires a substantial further perfection. Resin sulfonated Bayer K1221 is a co styrene-divinylbenzene commercially available gel-type resin, in beaded form. Its cross-linking degree is ca. 4% mol and therefore K1221 is expectedly quite similar to DOMA-VP and MTEMA-DMAA 4-4 for example. In fact ISEC analysis reveals a nanoporosity featured by 4.0 and 2.0 nm nanopores only. The expectation is that a Pd°/K1221 nanocomposite obtained with a classic procedure [5,9,10] will exhibit diameters strictly ranging from 2 to 4 nm. 

For example, Bayer in Germany is building a plant in Leverkusen to clean and compress by-product hydrogen from... 

For instance, in September 2004, Bayer settled 2861 product liability cases for 1.09 billion for its cholesterol medicine cerivastatin (Baycol), which was linked to 100 deaths and withdrawn from market in 2001. In July 2004, the company settled 2771 cases for 1.06 billion. Bayer still has 7577 additional cases to settle (see Section 28.4.4.5 for additional information). In another example, a 1 billion jury verdict was upheld against Wyeth for its fenfluramine or dexfenfluramine and phentermine (Fen-Phen) drug combination, which was linked to primary pulmonary hypertension (PPH). Wyeth has set aside 16.6 billion to cover future liability on the drug (see Section 28.4.4.2 for more on this case). ... 

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