Technical grades

Pyridine and quinoline are usually sold each in two grades, "technical" and "pure." The "technical" grade may contain various impurities which can hinder the identification of the base. 

Shipment, Stora.ge, ndPrice. Butenediol is available in unlined steel tank cars, tank trailers, and various sized dmms. Because of its relatively high freezing point, tank cars are fitted with heating coils. The 1991 U.S. bulk price of technical grade butenediol was about 5.36 /kg. 

Specifications and Analytical Methods. Purity is determined by gas chromatography. Technical grade butenediol, specified at 95%... 

Principal impurities are butynediol (specified as 2.0% maximum, typically less than 1%), butanediol, and the 4-hydroxybutyraldehyde acetal of butenediol. Moisture is specified at 0.75% maximum (Kad-Fischer titration). Typical technical grade butenediol free2es at about 8°C. 

The bottoms from the solvent recovery (or a2eotropic dehydration column) are fed to the foremns column where acetic acid, some acryflc acid, and final traces of water are removed overhead. The overhead mixture is sent to an acetic acid purification column where a technical grade of acetic acid suitable for ester manufacture is recovered as a by-product. The bottoms from the acetic acid recovery column are recycled to the reflux to the foremns column. The bottoms from the foremns column are fed to the product column where the glacial acryflc acid of commerce is taken overhead. Bottoms from the product column are stripped to recover acryflc acid values and the high boilers are burned. The principal losses of acryflc acid in this process are to the aqueous raffinate and to the aqueous layer from the dehydration column and to dimeri2ation of acryflc acid to 3-acryloxypropionic acid. If necessary, the product column bottoms stripper may include provision for a short-contact-time cracker to crack this dimer back to acryflc acid (60). 

UOP has developed a UOP Sorbex process for the recovery and purification of citric acid from fermentation broths. The process provides technical-grade citric acid, C HgOy, which can be further recrystaUized to obtain food-grade citric acid (qv). 

Standards for sulfuric acid, ranging from technical-grade through dmg-, food-, and reagent-grade, to electronic-grade are shown in Table 1. The advances in purity represented by these various grades of chemicals are based on the special uses of the chemicals. 

High purity hexafluorozirconic acid and its salts are produced by Advance Research Chemicals of the United States, and Akita and Moritta of Japan. The technical-grade green-colored material is suppHed by Cabot Corp. of the United States. In 1993, the U.S. market for fluorozirconic acid was about 250,000 kg/yr the world market was less than 500,000 kg/yr. A principal part of this production is consumed by the wool, garment, and upholstery industries. The 1993 price varied between 2.4 to 6.6/kg depending on the quaUty and quantity required. Potassium fluorozirconate [16923-95-8], K ZrF, is commercially important the world market is about 750,000 kg/yr. The most important appHcation is as a fire-retardant material in the wool (qv) industry, for the manufacture of garments, upholstery for aeroplane industry, and children s clothes (see Flame retardants). The 1993 unit price was between 5.0 and 6.6/kg. 

Table 8. 1993 Technical-Grade Hydrogen Peroxide Price Schedule ...

Hydroquinone is available in photographic, inhibitor, and technical grade. Manufacturer s specifications are given in Table 3. Table 3. Manufacturer s Specifications for Hydroquinone ... 

Shipping and Storage. MaHc acid is shipped in 50-lb, 100-lb, and 25-kg, multiwall paper bags or 100-lb (45.5 kg) fiber dmms. A technical-grade, 50% solution may be shipped in tank cars or tank tmcks. MaHc acid can be stored in dry form without difficulty, although conditions of high humidity and elevated temperatures should be avoided to prevent caking. 

Acetophenone can react with formaldehyde to yield light-resistant resins which are used as additives in nitrocellulose paints. It is also used as a photoinitiator, and in the pharmaceuticals, perfumery, and pesticide industries (344). It can be hydrogenated to 1-phenylethanol which is used for the production of aromatic ester fragrances (345). Technical-grade acetophenone is available at 2.29/kg perfume-grade acetophenone was 6.50/kg in October 1994. 

Property Technical grade Controlled particle size (CPS) " CPS-ultrafine (UF) usp"... 

The second method of preparation involves precipitation from a cold acidic solution of mercurous nitrate. Mercurous chloride is isolated after washing in a manner similar to the chamber method described. This product, which generally contains small amounts of occluded sodium nitrate, is satisfactory as a technical-grade material. Difficulty may be encountered in having it pass NF or reagent-grade specifications (see Fine chemicals). 

Chemical products are produced from technical-grade oxide in two very different ways. Molybdenum trioxide can be purified by a sublimation process because molybdenum trioxide has an appreciable vapor pressure above 650°C, a temperature at which most impurities have very low volatiUty. The alternative process uses wet chemical methods in which the molybdenum oxide is dissolved in ammonium hydroxide, leaving the gangue impurities behind. An ammonium molybdate is crystallized from the resulting solution. The ammonium molybdate can be used either directly or thermally decomposed to produce the pure oxide, MoO. ... 

AH the peroxides are colorless and diamagnetic when pure. Traces of the superoxide in technical-grade sodium peroxide impart a yellow color. Storage containers must be sealed to prevent reaction with atmospheric carbon dioxide and water vapor. 

Calcium peroxide is made by EMC, L Air Liquide, Nippon Peroxide (Japan), Shimakyo Chemical (Japan), Solvay Deutschland, Solvay Interox (United Kingdom), and Tomita Seiyaku (Japan). Trade names used for calcium peroxide are Calper, IXPER 60 C, IXPER 75 C, PermeOx, and Trap2ene. The world market for calcium peroxide ia 1992 was about 2000 t. The U.S. prices ia 1994 were, for the food-grade (75% Ca02), 3.97/kg and for the technical grade (60%), 2.97—3.30/kg. 

FIFRA Sections 3 and 4 pertain to registration and reregistration of pesticides, with clearly defined data requirements as outlined in Tide 40 of the US. Code of federal Regulations (51). About 120 different studies are Hsted, most of which are to be done on technical-grade active ingredients (TGAIs). 

Table 6. API Specifications for Technical-Grade High Viscosity CMC ...

Merchant-grade Technical-grade Technical-grade... 

Merchant-grade acid is purified to yield technical-grade. Socmtii Chimique Prayon-Rupel. 

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