Examples from Hoechst

Table 10 presents several examples (from Hoechst AG, Germany) for the use of master batch systems for TPO, the application field of additivated TPO, together with the maximum limit of the amount of additive (international regulation) required for the product use in contact with food [10]. 

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. 

Examples from patents [S. Haber and N. Egger, US Patent 6 140 265 (2000), to Clariant S. Haber and H.-J. Kleiner, US Patent 5 756 804 (1998), to Hoechst-Clariant] describe the synthesis of 2-cyano-4 -methylbiphenyl by reaction of 2-chlorobenzonitrile and p-tolueneboronic acid, in the presence of Na2C03, PdCl2, and triphenylphosphinetrisulfonic acid (4 mol) in a water-toluene system, with a co-solvent miscible with water such as DMSO or... 

FIGURE 16.2 An example of a very large-scale integrated (VLSI) circuit chip manufactured by IBM. (Reproduced with permission from Hoechst High Chem. Magazine, 1989). 

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... 

Fluorochromes can be attached to antibodies which will then bind to specific chemical structures on or inside cells. Many other chemical and physical properties of fluorochromes determine when and where these dyes are useful in various biological assays. For example, some of the fluorochromes that bind to DNA, such as Hoechst 33342, can get into living cells, but most DNA-binding fluorochromes cannot get past the cell membrane. Those fluorescent dyes that cannot get past an intact cell membrane, such as propidium iodide (PI), are often used to distinguish live from dead and dying cells. 

It was not until the pioneering studies of Bestian, Clauss and Beermann at Farbwerke Hoechst, that a number of methyltitanium alkoxides and chlorides were prepared in high yields, isolated and characterized 31). Later, additional examples and improvements were reported 1,19,28 32). Methyltitanium triisopropoxide 6 is readily prepared by quenching methyllithium with 5, decanting from the inorganic precipitate and distilling at 0.01 torr/50 °C (95% yield)31b,32). 

Oxidation of aldehyde products produced from hydro-formylation is a major industrial route to carboxylic acids. The Hoechst-Celanese Corporation, for example, produces considerable quantities of linear C7 and C9 carboxylic acids from the Rh/PPh3-catalyzed hydroformylation of 1-hexene and 1-octene. 

Matters inevitably become even more difficult when fundamental cultural differences are compounded by linguistic ones. This was a particular challenge, for example, in the formation of Aventis from the merger of Hoechst and Rhone-Pou-lenc s pharmaceuticals and agrochemicals activities. 

The orientation of the ligand was similarly determined in the 1 1 complexes based on intermolecular NOEs between protons located at the extremities of the Hoechst molecule and protons of the binding site. F or example, in the interaction with d(GTGGAATTCCAC)2, Fede et al. (106) reported NOEs between protons from the piperizine moiety and the H2 and HI protons of the dinucleotide fragment d(A5T5) d(A6T6). 

Semisynthesis has become a suitable technique for chemical variations of large polypeptides or proteins from natural sources. Human insulin differs from porcine insulin only in position B30, where alanine is the C-terminal B-chain residue of porcine insulin but threonine is the C-terminal of the human insulin B-chain. Among the various ways to obtain human insulin from porcine insulin by protease-catalyzed semisynthesis, the one-step conversion by exchange of the C-terminal alanine B of porcine insulin with a threonine residue seems to be the method of choice. Several proteases, e.g. trypsin, achromobacter protease, and car-boxypeptidase Y, are able to catalyze the conversion and various groups have independently described an essential improvement of the enzymatic semisynthesis of insulin.The Hoechst procedure,which was developed as an industrial process, is described below as an example of a large-scale conversion of porcine insulin to human insulin in kilogram amounts for therapeutic application. Based on this type of transamidation reaction, it is easy to prepare various B30-insulin analogues. 

Only a small minority of organometallic reactions have cleared the hurdle to become catalytic reality in other words, catalyst reactivation under process conditions is a relatively rare case. As a matter of fact, the famous Wacker/Hoechst ethylene oxidation achieved verification as an industrial process only because the problem of palladium reactivation, Pd° Pd", could be solved (cf. Section 2.4.1). Academic research has payed relatively little attention to this pivotal aspect of catalysis. However, a number of useful metal-mediated reactions wind up in thermodynamically stable bonding situations which are difficult to reactivate. Examples are the early transition metals when they extrude oxygen from ketones to form C-C-coupled products and stable metal oxides cf. the McMurry (Ti) and the Kagan (Sm) coupling reactions. Only co-reactants of similar oxophilicity (and price ) are suitable to establish catalytic cycles (cf. Section 3.2.12). In difficult cases, electrochemical procedures should receive more attention because expensive chemicals could thus be avoided. Without going into details here, it is the basic, often inorganic, chemistry of a catalytic metal, its redox and coordination chemistry, that warrant detailed study to help achieve catalytic versions. 

Apart from the oxo process, a series of other reactions are carried out industrially, even if on a smaller scale. Kuraray carries out the hydrodimerization of butadiene and water to produce n-octanol (or 1,9-nonanediol) on a scale of about 5000 metric tons per year [55]. Applications which are significantly smaller up to now are, for example, the production of vitamin precursors by Rh6ne-Poulenc (cf. Scheme 2, [56]) and the production of substituted phenylacetic acids by carbonylation (Scheme 3) [57]) or of biaryls by Suzuki cross coupling (Scheme 4), both by Hoechst AG (now Clariant AG, [57,58]). 

Liquid crystalline aromatic polyamides were the first chemical class to be commercialised. The best known example is Kevlar fibre which is spun from liquid crystalline solution to obtain the benefit of the high orientation present in the nematic phase. Subsequently, melt-processable main-chain polyesters were developed and brought to the market (Amoco with Xydar, Hoechst-Celanese with Vectra). 

An environmental load factor may be negative, which means that the weight of product formed exceeds the weight of materials wasted. An example comes from the Hoechst company in Germany, of which the fipco... 

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