Chemical methods of preparing

Solution Deposition of Thin Films. Chemical methods of preparation may also be used for the fabrication of ceramic thin films (qv). MetaHo-organic precursors, notably metal alkoxides (see Alkoxides, metal) and metal carboxylates, are most frequently used for film preparation by sol-gel or metallo-organic decomposition (MOD) solution deposition processes (see Sol-GEL technology). These methods involve dissolution of the precursors in a mutual solvent control of solution characteristics such as viscosity and concentration, film deposition by spin-casting or dip-coating, and heat treatment to remove volatile organic species and induce crystaHhation of the as-deposited amorphous film into the desired stmcture. 

Acharya, H. N Bose, H. N. 1971. A chemical method of preparing photoconducting lead sulphide films. Phys. Stat. Sol. 6(a) K43-K44. 

After some model reactions, Ugi et al. accomplished a new way of preparing Xylocaine by one of the first U-4CRs. In 1944 Xylocaine 12 (Scheme 1.4) was introduced by the A. B. Astra company in Sweden, and since then Xylocaine has been one of the most often used local anasthetics, particularly by dentists. In its early period, A. B. Astra patented 26 chemical methods of preparing 12. 

This handbook is an encyclopedic treatment of chemical elements and their most important compounds intended for professionals and students in many areas of chemistry throughout the manufacturing, academic, and consulting communities. Chemicals are presented in alphabetical order in a descriptive format highlighting pertinent information on physical, chemical, and thermodynamic properties of chemicals, methods of preparation, industrial applications, chemical analyses, and toxic and hazardous properties. Synonyms, CAS Registry Numbers, brief history of discovery and natural occurrence are provided for many entries. The objective is to provide readers a single source for instant information about important aspects each substance. In this sense it should serve as a combination handbook and encyclopedia. 

Chemical methods of preparing nanoparticles offer many possibilities - the case of metal particles being illustrative. Microemulsions and micelles can be employed as the media to produce small particles of sulfides and oxides of 1.5-10 nm diameter with narrow size distribution (e.g. CdS). The sol-gel technique also gives small particulates of many oxidic materials. Recently, homogeneous nanoparticles of ZnO and of the... 

Suykovskaya N.V., Chemical Methods of Preparation of Thin Transparent Films. Khimiya, Leningrad, 1971. 

According to Ref. 32, there is no formation of free phthalocyanine in the system "z-BuOII CII3ONa ( -Bu)4NBr o-phthalonitrile without the application of electrolysis at about 100°C (Example 11), unlike some other solvents where both chemical and electrochemical formation of phthalocyanine could take place. So, this solvent was chosen by the authors of Ref. 33 in order to synchronize metal anode dissolution with the formation of free phthalocyanine on the cathode surface and to avoid obtaining a mixture of metal-free phthalocyanine-lanthanide phthalocyanine. Unlike conventional chemical methods of preparing rare-earth metal phthalocyanines [63,85,86], where the syntheses are carried out at 170-290°C, it is possible to decrease the reaction temperature to about 100°C. 

Most relevant for the oxygen transport should be the defective crystal structure of both catalyst components. The defective structure and the intimate contact of crystallites of the various phases are direct consequences of the fusion of the catalyst precursor and are features which are inaccessible by conventional wet chemical methods of preparation. Possible alternative strategies for the controlled synthesis of such designed interfaces may be provided by modem chemical vapor deposition (CVD) methods with, however, considerably more chemical control than is required for the fusion of an amorphous alloy. 

For synthetic purposes, NeuSAc has been isolated from a number of natural sources, including edible bird s nest (2-11% sialic acid by weight) [S-7] and submaxillary gland mucins which contain as much as 1S-2S% sialic acid on a dry weight basis [8, 9]. However the need for a more convenient source of NeuSAc has led to the investigation of both enzymic and chemical methods of preparation. 

The first cyclic intermediate on the shikimate pathway is 3-dehydro-quinic acid (38) and it was first obtained by Weiss, Davis and Mingioli from cultures of Escherichia coli mutant 170-27 by charcoal chromatography and precipitation of the brucine salt. Probably the first chemical preparation of this biochemical intermediate was reported by Hesse in 1859 who oxidised (—)-quinic acid (42) with bromine water Several procedures have since been reported for the preparation of this metabolite Yields of almost 80 per cent of 3-hydroquinic acid (38) were reported by Whiting and Coggins after a seven-day incubation of (—)-quinic acid (42) with Acetomonas oxydans CR-49 and similar selective oxidation of the axial 3-hydroxyl group in (—)-quinic acid with nitric acid or platinum and oxygen " forms the basis of chemical methods of preparation. 

The chemical method of preparation of the intermediate places severe restrictions on the possible structures for the active compound. Since... 

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