Chemicals and solvents

Benzene [71-43-2] toluene [108-88-3] xylene [1330-20-7] and solvent naphtha are separated from the light oil. Benzene (qv), toluene (qv), and xylene are useful as solvents and chemical intermediates (see Xylenes and ethylbenzene). The cmde light oil is approximately 60—70% ben2ene, 12—16% toluene, 4—8% xylenes, 9—16% other hydrocarbons, and about 1% sulfur compounds (5) (see BTX processing). 

Ketones are an important class of industrial chemicals that have found widespread use as solvents and chemical intermediates. Acetone (qv) is the simplest and most important ketone and finds ubiquitous use as a solvent. Higher members of the aUphatic methyl ketone series (eg, methyl ethyl ketone, methyl isobutyl ketone, and methyl amyl ketone) are also industrially significant solvents. Cyclohexanone is the most important cycHc ketone and is primarily used in the manufacture of y-caprolactam for nylon-6 (see Cyclohexanoland cyclohexanone). Other ketones find appHcation in fields as diverse as fragrance formulation and metals extraction. Although the industrially important ketones are reviewed herein, the laboratory preparation of ketones is covered elsewhere (1). 

World methanol consumption for 1992 is shown in Figure 10 (27). The principal use of methanol has traditionally been in the production of formaldehyde [50-00-0] where typically around 40% of the world methanol market is consumed. In the United States, an increasing role for methanol has been found in the oxygenated fuels market from the use of MTBE. Another significant use of methanol is in the production of acetic acid other uses include the production of solvents and chemical intermediates. 

Nitrocellulose based lacquers often contain short or medium oil alkyds to improve flexibiUty and adhesion. The most commonly used are short oil non drying alkyds. Amino resins or urethane resins with residual isocyanate functional groups may be added to cross-link the coating film for improved solvent and chemical resistance. The principal appHcations are furniture coatings, top lacquer for printed paper, and automotive refinishing primers. 

Solubility and Solution Properties. Poly(vinyhdene chloride), like many high melting polymers, does not dissolve in most common solvents at ambient temperatures. Copolymers, particularly those of low crystallinity, are much more soluble. However, one of the outstanding characteristics of vinyUdene chloride polymers is resistance to a wide range of solvents and chemical reagents. The insolubiUty of PVDC results less from its... 

Other types of regenerators designed for specific adsorption systems may use solvents and chemicals to remove susceptible adsorbates (51), steam or heated inert gas to recover volatile organic solvents (52), and biological systems in which organics adsorbed on the activated carbon during water treatment are continuously degraded (53). 

PZN-PT, and YBa2Cug02 g. For the preparation of PZT thin films, the most frequently used precursors have been lead acetate and 2irconium and titanium alkoxides, especially the propoxides. Short-chain alcohols, such as methanol and propanol, have been used most often as solvents, although there have been several successful investigations of the preparation of PZT films from the methoxyethanol solvent system. The use of acetic acid as a solvent and chemical modifier has also been reported. Whereas PZT thin films with exceUent ferroelectric properties have been prepared by sol-gel deposition, there has been relatively Httle effort directed toward understanding solution chemistry effects on thin-film properties. 

Particular pieces of apparatus and chemicals and solvents of exactly defined quality were employed in the examples that follow and it is necessary to define them precisely. Manufacturers names have been given when necessary as defining a quality criterion. The purity of solvents and chemicals is a particularly important point. 

Ethanol s many uses can be conveniently divided into solvent and chemical uses. As a solvent, ethanol dissolves many organic-based materials such as fats, oils, and hydrocarbons. As a chemical intermediate, ethanol is a precursor for acetaldehyde, acetic acid, and diethyl ether, and it is used in the manufacture of glycol ethyl ethers, ethylamines, and many ethyl esters. 

ASTM D 268-96, Guide for Sampling and Testing Volatile Solvents and Chemical Intermediates for Use in Paint and Related Coatings and Materials, Annual Book of ASTM Standards, ASTM, West Conshohocken, PA (1998), Vol. 06.04. 

Nanoparticle surface modification is of tremendous importance to prevent nanoparticle aggregation prior to injection, decrease the toxicity, and increase the solubility and the biocompatibility in a living system [20]. Imaging studies in mice clearly show that QD surface coatings alter the disposition and pharmacokinetic properties of the nanoparticles. The key factors in surface modifications include the use of proper solvents and chemicals or biomolecules used for the attachment of the drug, targeting ligands, proteins, peptides, nucleic acids etc. for their site-specific biomedical applications. The functionalized or capped nanoparticles should be preferably dispersible in aqueous media. 

Monomethylhydrazine is a clear, colorless liquid used extensively in military applications as a missile and rocket propellant, in chemical power sources, and as a solvent and chemical intermediate. Upon contact with strong oxidizers (e.g., hydrogen peroxide, nitrogen tetroxide, chlorine, fluorine) spontaneous ignition may occur. 

Used industrially as a solvent and chemical intermediate for insecticides, acaricides, herbicides, and defoliants. It is used in agriculture as a deer repellant. 

Besides using pure and non-electro-active solvents and chemicals (see Mobile Phase in Chapter 4) for the mobile phase to reduce background current the relationship between working electrode potential and background current must be determined before you can select the optimum working electrode potential for analysis of the substance. 

The small range of azo condensation pigments has become established only because they combine outstanding fastness to light, heat, solvents and chemicals, finding acceptance for use in paints, printing inks and the coloration of plastics and some synthetic fibres. 

Wet spinning. This technique is characterized by spinning a filtered viscous polymer mass, dissolved in a suitable solvent, into contact with a precipitation or coagulation bath. Polyacrylonitrile, polyvinyl acetate, cellulose acetate, and other materials are processed by this method. Thermal requirements for pigments are less stringent than for melt spinning but pigments are expected to be fast to the solvents and chemicals used. 

Its fastness to organic solvents and chemicals corresponds to that of other representatives of group II Naphthol AS pigments (Sec. 2.6.2). Consequently, P.R.253 is almost completely fast to overpainting. 

Naphthol AS pigment series. Excellent fastness to solvents and chemicals is accompanied by good migration fastness. Benzimidazolone pigments do not bloom, and most of them show good and some even excellent bleed fastness and fastness to overcoating. All benzimidazolone pigments, with one exception (P.Y.151), are inert to alkali and acid. Most of them disperse easily in the common application media. 

P.R.168 is found to a lesser extent in printing inks and plastics. The printing ink industry utilizes P.R.168 to produce special-purpose printing inks, which may be applied to substrates such as posters or metal deco prints. The pigment demonstrates equally excellent fastness in these materials. 1/1 SD systems equal step 8 on the Blue Scale for lightfastness, while 1/3 to 1/25 SD formulations match step 7. The prints are resistant to common organic solvents and chemicals. The pigment is thermally stable up to 220°C for 10 minutes, and its prints may safely be sterilized. 

Chemicals and Nanoparticles. All chemicals were used without further treatment. Anhydrous solvents and chemicals were stored in a drybox and used under dry nitrogen gas. 

Decisive characteristics of porous separators ( diaphragms ) are porosity, pore diameter, and thickness. For practical use, other aspects such as mechanical strength (brittle or flexible), constant dimensions (swelling in the solvent), and chemical stability are important. 

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