Hoechst materials

Acetaldehyde, first used extensively during World War I as a starting material for making acetone [67-64-1] from acetic acid [64-19-7] is currendy an important intermediate in the production of acetic acid, acetic anhydride [108-24-7] ethyl acetate [141-78-6] peracetic acid [79-21 -0] pentaerythritol [115-77-5] chloral [302-17-0], glyoxal [107-22-2], aLkylamines, and pyridines. Commercial processes for acetaldehyde production include the oxidation or dehydrogenation of ethanol, the addition of water to acetylene, the partial oxidation of hydrocarbons, and the direct oxidation of ethylene [74-85-1]. In 1989, it was estimated that 28 companies having more than 98% of the wodd s 2.5 megaton per year plant capacity used the Wacker-Hoechst processes for the direct oxidation of ethylene. 

In the late 1980s, new fully aromatic polyester fibers were iatroduced for use ia composites and stmctural materials (18,19). In general, these materials are thermotropic Hquid crystal polymers that are melt-processible to give fibers with tensile properties and temperature resistance considerably higher than conventional polyester textile fibers. Vectran (Hoechst-Celanese and Kuraray) is a thermotropic Hquid crystal aromatic copolyester fiber composed of -hydroxyben2oic acid [99-96-7] and 6-hydroxy-2-naphthoic acid. Other fully aromatic polyester fiber composites have been iatroduced under various tradenames (19). 

Hoechst-Celanese Chemical Group International Product Index, Sept., 1991 Material S afety Data Sheets, Hoechst-Celanese, Corp., Dallas, Tex., 1991. 

Catalytic oxidation ia the presence of metals is claimed as both nonspecific and specific for the 6-hydoxyl depending on the metals used and the conditions employed for the oxidation. Nonspecific oxidation is achieved with silver or copper and oxygen (243), and noble metals with bismuth and oxygen (244). Specific oxidation is claimed with platinum at pH 6—10 ia water ia the presence of oxygen (245). Related patents to water-soluble carboxylated derivatives of starch are Hoechst s on the oxidation of ethoxylated starch and another on the oxidation of sucrose to a tricarboxyhc acid. AH the oxidations are specific to primary hydroxyls and are with a platinum catalyst at pH near neutraUty ia the presence of oxygen (246,247). Polysaccharides as raw materials ia the detergent iadustry have been reviewed (248). 

Dicyclopentadiene (24) [77-73-6] is an inexpensive raw material for hydrocyanation to (25), a mixture of l,5-dicarbonittile [70874-28-1] and 2,5-dicarbonittile [70874-29-2], then subsequent hydrogenation to produce tricyclodecanediamine, TCD diamine (26). This developmental product, a mixture of endo and exo, cis and trans isomers, is offered by Hoechst. 

These materials also have high thermal and oxidative stabiHty. Flexible segments such as amide siloxane can be incorporated into the imide-based stmcture for hot melt or injection appHcations. General Electric (GE) and Hoechst-Celanese are suppHers of these high performance plastics. 

These LCT materials have very high tensile and flexural strength, and excellent mechanical and chemical resistance properties. Some commercial LCT are Vectra (Hoechst-Celanese) and Xydar (Amoco). Du Pont, ICI, GE, and Dow Chemical are also suppHers. Their appHcation in electronic embedding is stiU. in its infancy because of the high temperature processing requirement. Nevertheless, this class of thermoplastic polymers will play an important role in electronic embedding. 

PPS resins must compete with PEI and phenoHcs. There are two domestic manufacturers of poly(phenylene sulfide) Phillips and Fortron Industries. Worldwide there is currently large overcapacity (Table 15). Four Japanese companies, ie, Toso Susteel, a joint venture of Toso/Hodogaya Chemical Toray Toprene, a joint venture of Toto Kasei/Toren Petrochemical and Kureha Chemical have a combined capacity of 82,500 t. U.S. agents sell their materials in the U.S. markets General Electric sells for Toso Susteel Soltex Polymer, part of Solvay, Belgium, sells for Toprene Hoechst-Celanese sells for Kureha. Prices for PPS resins and compounds range from 8.80/kg for unreinforced resin to 3.30/kg for 65% filled resins. 

Four companies (trade name in parentheses), Amoco (Xydar), Hoechst-Celanese (Vectra), Du Pont, and Granmont (Granlar), make thermotropic LCPs for various types of extmsion and mol ding processes. Six companies have discontinued TCP materials that were either commercial or under development. These companies include ICl, BASF, Eastman, Bayer, General Electric, and Monsanto. 

Other companies offering similar materials are Du Pont, BASE, and Hoechst-Celanese. PEEK is a difficult resia to manufacture because of batch procedures and iasolubiUty. 

Ethylene-cyclo-olefin copolymers have been known since 1954 (DuPont USP2 721 189) but these materials only became of importance in the late 1990s with the development of copolymers of ethylene and 2-norbomene by Hoechst and Mitsui using metallocene technology developed by Hoechst. The product is marketed as Topas by Ticona. By adjustment of the monomer ratios polymers with a wide range of Tg values may be obtained including materials that are of potential interest as thermoplastic elastomers. This section considers only thermoplastic materials, cyclo-olefins of interest as elastomers are considered further in Section 11.10. 

In addition to the presence of stable C—F bonds, the PTFE molecule possesses other features which lead to materials of outstanding heat resistance, chemical resistance and electrical insulation characteristics and with a low coefficient of friction. It is today produced by a number of chemical manufacturers such as Du Pont (Teflon), ICI (Fluon), Hoechst (Hostaflon TF), Rhone-Poulenc (Soreflon), Montecatini (Algoflan), Nitto Chemical-Japan (Tetraflon) and Daikin Kogyo-Japan (Polyflon). 

In the mid-1980s Hoechst introduced a related material, Hostaflon TFB, a terpolymer of tetrafluoroethylene, hexafluoropropene and vinylidene fluoride. 

In 1972 Du Pont introduced Teflon PFA, a copolymer of tetrafluoroethylene and perfluorofpropyl vinyl ether) (CF2 = CFOCF2CF2CF3). Similar materials are now also produeed by Asahi Glass, Daikin, Hoechst and Monteflos and are commonly referred to as PFA fluoropolymers. In 1994 Hoechst introduced Hostaflon PFA-N, claimed to have significantly lower melt viscosities than earlier grades of material. 

The first commercially available acetal resin was marketed by Du Pont in 1959 under the trade name Delrin after the equivalent of ten million pounds had been spent in research or polymers of formaldehyde. The Du Pont monopoly was unusually short lived as Celcon, as acetal copolymer produced by the Celanese Corporation, became available in small quantities in 1960. This material became commercially available in 1962 and later in the same year Farbwerke Hoechst combined with Celanese to produce similar products in Germany (Hostaform). In 1963 Celanese also combined with the Dainippon Celluloid Company of Osaka, Japan and Imperial Chemical Industries to produce acetal copolymers in Japan and Britain respectively under the trade names Duracon and Alkon (later changed to Kematal). In the early 1970s Ultraform GmbH (a joint venture of BASF and Degussa) introduced a copolymer under the name Ultraform and the Japanese company Asahi Chemical a homopolymer under the name Tenal. 

Blends or alloys of polyacetals with polyurethane elastomers were first introduced by Hoechst in 1982, who were then followed by other manufacturers. The key features of these materials are their improved toughness with little change in other important properties. There are two aspects with respect to the impact toughness ... 

Polyether ketone (PEK) (structure A). In 1986 three European companies (BASF, Hoechst and ICI) announced they were developing the material (to be marketed under the trade names of Ultrapek, Hostatec and Victrex PEK respectively). 

Polyether ether ketone ketone (PEEKK), the latest material to be introduced (Hostatec X—Hoechst). 

Polymers based on these structures became available as Victrex SRP (ICI), Vectra (Hoechst) and Xydar (Amoco). It is reported that the Vectra materials are based on p-hydroxybenzoic acid and hydroxynaphthoic acid monomers, whilst Xydar is based on terephthalic acid, p-hydroxybenzoic acid and pp -dihydrox-ybiphenyl. Whilst properties vary between grades, in general they possess the following outstanding properties ... 

The TLCP used was a widely investigated one, Vectra A950, manufactured by Hoechst-Celanese. The PC was produced by Enichem under the tradename Sinvet 303. Table 3 lists the main properties of these materials according to the manufacturers. The materials were dried in a vacuum oven at 120°C for 4 h before processing. Prior to injection molding of the composite samples, two components were melt mixed by a ZSK, W P, Stuttgart, extruder with a constant weight ratio of PC-TLCP = 80 20 [23]. 

A number of material suppliers offer information on their products on electronic devices (floppy discs, CDs, etc.) for use on personal computers. An important one, called Campus, is a database concept started by four German material manufacturers who use a uniform software. This database, initially developed jointly by BASF, Bayer, Hoechst, and Hulls, provided for other manufacturers to join. The present consortium has more than 50 materials suppliers worldwide. It is given in the form of diskettes in German, English, French, Italian, or Spanish. Each diskette contains the uniform test and evaluation program and the range of the respective material producers. It runs on IBM-compatible personal computers under the MS-DOS operating system. 

Polylactides, 18 Poly lactones, 18, 43 Poly(L-lactic acid) (PLLA), 22, 41, 42 preparation of, 99-100 Polymer age, 1 Polymer architecture, 6-9 Polymer chains, nonmesogenic units in, 52 Polymer Chemistry (Stevens), 5 Polymeric chiral catalysts, 473-474 Polymeric materials, history of, 1-2 Polymeric MDI (PMDI), 201, 210, 238 Polymerizations. See also Copolymerization Depolymerization Polyesterification Polymers Prepolymerization Repolymerization Ring-opening polymerization Solid-state polymerization Solution polymerization Solvent-free polymerization Step-grown polymerization processes Vapor-phase deposition polymerization acid chloride, 155-157 ADMET, 4, 10, 431-461 anionic, 149, 174, 177-178 batch, 167 bulk, 166, 331 chain-growth, 4 continuous, 167, 548 coupling, 467 Friedel-Crafts, 332-334 Hoechst, 548 hydrolytic, 150-153 influence of water content on, 151-152, 154... 

Hoechst AG, Hostapur SAS the raw material with a sure future, 1987. 

Hoechst has developed a ehemieal reeyeling plastie for Hostaform, a polyaeetal engineering material. Post-use engineering parts and produetion serap are recovered and converted back into the original monomers by depolymerisation. They are then repolymerised to form plastics with the same molecular structure as before, without loss of quality. The process at Hoechst s laboratory and pilot plant operations is outlined. EUROPEAN COMMUNITY GERMANY WESTERN EUROPE Accession no.497548... 

Three studies examined the effects of endosulfan exposure on reproductive performance in rats. Consumption of estimated doses of endosulfan of up to 9 and 8 mg/kg/day by male and female rats, respectively, for 2 weeks prior to mating and continued consumption throughout gestation resulted in no adverse effect on mating performance, pregnancy rate, or gestation (Hoechst 1982). This study is limited in that the actual intake of test material was quantified only during the first 2 weeks of exposure, and a relatively small number of animals was used. Similarly, consumption of 5 mg/kg/day by male rats and... 

Die Natur der Chemie, FUTURE (Hoechst Magazin), August 1996 Vision of large-scale production in shoebox-sized plants nature and plant ceUs as model for micro reactors sustainable development central role of catalysis general advantages of micro flow use of clean raw materials minimization of waste the next step in the sequence acetylene-to-efhylene chemistry ethane chemistry renewable resources combinatorial chemistry intelligent and creative solutions [229]. 

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