Preferred Commercial Form

On one hand, there is an equilibrium between keto form molecules and oxide form molecules, and on the other hand there is an equilibrium between oxide form molecules and dimer molecules. A superposition of these two equilibria means that from a liquid monomer mixture of keto form and oxide form molecules obeying the first equilibrium, some solid dimer crystals must form to satisfy the second equilibrium. However, this dimer formation 

The liquid obtained by melting the dimer consists at first of oxide form molecules which require days until the equilibrium mixture of keto form and oxide form molecules is reached. During this conversion, the smell changes as on account of the unlike structure the smell of oxide form molecules differs from that of keto form molecules. This must be considered when the liquid is submitted to olfactory tests. 

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Chitin was first isolated from mushroom tissue and named fungine in 1811 by Braconnot, a French botanist. A similar material was isolated by Odier from insect exoskeleton, which he termed chitine (1). Chitin is considered the second most plentiful biomaterial, following cellulose. The annual production of chitin biomass has been estimated at 1 x 10 kg worldwide (2). This has led to considerable scientific and technological interest in chitin and chitosan. Chitosan has become the preferred commercial form of this material as it is more tractable than chitin. Chitin is insoluble in most common solvents, whereas chitosan dissolves in many common aqueous acidic solutions. Chitosan has foimd applications in many primary industries such as agriculture, paper, textiles, and wastewater... 

Once this process has been completed for each of the essential elements, patent claims maybe drafted which cover the invention. These claims will cover, in the broadest sense, only those elements of the invention which are essential. Narrower, more focused claims, however, should also be included within the patent appHcation. These claims may focus on aspects of the invention that the appHcant beHeves are preferred, or may otherwise represent essential aspects of any commercial product that will stem from the invention. Finally, claims should also be drafted to cover alternative forms of the invention. Such alternative forms of the invention may not necessarily be considered to be preferred commercially, but they may present an area where a competitor could attempt to engineer "around" the invention. 

Polymerization to Polyether Polyols. The addition polymerization of propylene oxide to form polyether polyols is very important commercially. Polyols are made by addition of epoxides to initiators, ie, compounds that contain an active hydrogen, such as alcohols or amines. The polymerization occurs with either anionic (base) or cationic (acidic) catalysis. The base catalysis is preferred commercially (25,27). 

Preparation of virtual screening databases starts with standardization of the input SMILES. This procedure was originally developed to deal with databases from commercial suppliers. Preferred tautomeric forms are generated in this step and ionized species are neutralized. Ionization states are set in the second step for biased equilibria and multiple forms are enumerated in a third step to represent balanced equilibria. The model treats an equilibrium as balanced if the equilibrium constant associated with its defining rule is likely to be less than about 1.5 log units. 

There are several different routes to carboxamides. In most of these reactions, a carboxylic acid is converted to a more reactive intermediate, e.g. the acid chloride, which is then allowed to react with an amine. For practical reasons, it is preferable to form the reactive intermediate in situ. Arylboronic acids with electron-withdrawing groups such as (3,4,5-trifluorophenyl)boronic acid act as highly efficient catalysts in the amidation between carboxylic acids and amines. (3-Nitrophenyl)boronic acid and [3,5-bis(trifluoromethyl)phenyl]boronic acid are also effective eimidation catalysts and commercially available. 

A major selectivity advantage of biological catalysts over traditional systems includes the ability to form single products (chemical selectivity) as well as single optical isomers (stereoselectivity). Specific examples where biological routes are preferred commercially include fermentative processes for the amino acids monosodium glutamate (MSG), lysine, aspartic acid, citric acid and phenylalanine (5). Many other chemicals have also been produced by fermentative processes (6). 

Commercially, aciylamide is formed from aciylonitrile by reaction with water. Similarly, the preferred commercial route to methaciylamide is through methacrylonitrile. Acrylamide polymerizes by a free-radical mechanism. Water is the common solvent for acrylamide and methacrylamide polymerizations, because the polymers precipitate out from organic solvents. 

The majority of the commercial metal stearates (besides special grades) are produced by a reaction of certain metal hydroxides or oxides with hydrogenated tallow fatty acids (HTFA) or mixtures of stearic and palmitic acids. Dependent on the production process applied (direct fusion in molten fatty acid or precipitation in an excess of water) a broad range of qualities (from neutral to high base excess) is available in various commercial forms. Concerning polymer apphcations, a nearly neutral grade of high purity and heat stability, i.e. with low acid content and low amount of water soluble salts (basicity), should be preferred. 

By treatment with anhydrous aluminium chloride (Holmes and Beeman, 1934). Ordinary commercial, water-white benzene contains about 0 05 per cent, of thiophene. It is first dried with anhydrous calcium chloride. One litre of the dry crude benzene is shaken vigorously (preferably in a mechanical shaking machine) with 12 g. of anhydrous aluminium chloride for half an hour the temperature should preferably be 25-35°. The benzene is then decanted from the red liquid formed, washed with 10 per cent, sodium hydroxide solution (to remove soluble sulphur compounds), then with water, and finally dried over anhydrous calcium chloride. It is then distilled and the fraction, b.p. 79-5-80-5°, is collected. The latter is again vigorously shaken with 24 g. of anhydrous aluminium chloride for 30 minutes, decanted from the red liquid, washed with 10 per cent, sodium hydroxide solution, water, dried, and distilled. The resulting benzene is free from thiophene. 

M-type ferrites are mainly used as permanent magnet material. They have largely replaced the alnicos as preferred permanent magnet material, as a result of the lower material and processing costs. These ferrites were first introduced under the trade name Ferroxdure, the isotropic form in 1952 (22) and the anisotropic (crystal oriented) form in 1954 (23), and are widely available commercially under various trade names such as Oxid and Koerox. They cover about 55% of the world market of permanent magnet materials, corresponding to 1100 million U.S. doUars (1991), as weU as 55% of the U.S. market, at 300 million. 

Oxidation. Naphthalene may be oxidized direcdy to 1-naphthalenol (1-naphthol [90-15-3]) and 1,4-naphthoquinone, but yields are not good. Further oxidation beyond 1,4-naphthoquinone [130-15-4] results in the formation of ortho- h. h5 ic acid [88-99-3], which can be dehydrated to form phthaUc anhydride [85-44-9]. The vapor-phase reaction of naphthalene over a catalyst based on vanadium pentoxide is the commercial route used throughout the world. In the United States, the one phthaUc anhydride plant currently operating on naphthalene feedstock utilizes a fixed catalyst bed. The fiuid-bed process plants have all been shut down, and the preferred route used in the world is the fixed-bed process. 

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