Production standards, grades

The autoclave is then charged once with ethylene to 10 atm and vented (to flush air out of the connections to the gas bottle) and then charged with ethylene (Air Products, standard grade) to 48 atm, and set rocking at 20 times per minute. The temperature is gradually raised to 200°, so that the difference between the temperatures inside and outside the autoclave does not exceed 20°. The temperature is then maintained at 200 ° for 19 hours. 

Ammonium bicarbonate is produced as both food and standard grade and the available products are normally very pure. Although purification is possible by sublimation at low temperatures, it is more economical to prepare the desired product directiy by using ammonia and carbon dioxide of high purity. 

Reduction of standard-grade products (niche products to independent compounders)... 

Two PET grades now dominate the global market, i.e. fibre-grade PET and bottle-grade PET. These standard grades differ mainly in molecular weight or intrinsic viscosity (IV), respectively, optical appearance and the production recipes. The latter differ in the amount and type of co-monomers, stabilizers and metal catalysts, as well as colorants. 

Other PET grades are manufactured for packaging films, as well as for the production of video and audio tapes. These PET types are often standard grades with an IV of 0.64 dL/g. To reduce the sticking tendency of the final product, solid additives such as Si02 or china clay with specific particle sizes and particle-size distributions are incorporated by master-batch processes. The final product, the so-called BOPET, is a biaxial oriented PET film with high mechanical strength and a thickness between 1 and 180 im. 

Raw rubber can be either natural or synthetic. The standard grades of natural rubber are smoked sheets and pale crepe. For high grade products, first grade smoked sheets, namely RMAIX or Pale Crepe, is used. Pale Crepe is practically colourless and is preferred in products where delicate colour, extreme whiteness or transparency... 

United States Standards for Grades of Frozen Concentrated Orange Juice Effective Feb. 17, 1976, Section 52.1582(a) Without Sweetener. United States Department of Agriculture, Agricultural Marketing Service, Fruit Safety and Quality Service, Processed Products Standardization and Inspection Branch, Washington, D.C. 

The preparation of Ce(IV) compounds free of foreign metals is facilitated by the fact that, when ammonium nitrate is added to a concentrated nitric add solution of Ce(IV), the compound (NH4)2Ce(N03)g is precipitated in relatively pure form. Because the Ce(rV) exists as the complex ion Ce(N03)g", the ammonium salt is properly caUed ammonium hexanitratocerate(TV). In water and in dilute nitric acid, extensive dissodation occurs. Ammonium hexanitratocerate(IV) was suggested as a primary standard, and drying it to constant weight at 100°C was recommended. Later it was recognized that slow decomposition occurs at this temperature, and Smith and Fly recommended a procedure that involved drying a product of primary-standard grade at 85°C for 1 to 6 h. The accurate results of Smith and Fly have been confirmed. ... 

Accurate coulometric titrations have indicated a purity of 99.96 to 99.98% for hexanitratocerate products of low thorium content. Two older preparations containing 0.22 and 0.79% thorium as (NHjjThlKOa) gave assays of 99.4 and 98.7%. Apparently the NH3 content has never been accurately checked to determine whether compensation of errors could occur. Appreciable amounts (0.1 to 0.5%) of Ce(III) in primary-standard grade hexanitratocerate have been found by direct titration of Ce(III) to Ce(IV) with ferricyanide in carbonate medium. 

Standard-grade, commercial lecithin from the soybean is a complex mixture. It comprises phospholipids, triglycerides, and minor amounts of other constituents (i.e., phytoglycolipids, phytosterols, tocopherols, and fatty acids). The composition and molecular arrangement of this heterogeneous mixture of compounds defines a product that is low in apparent polarity and has a strong tendency to promote water-in-oil (w/o)-type emulsions (31). 

Solubilization. Most lecithins can aid in the production of microemulsions, an example being oil-soluble flavors in aqueous systems. Although standard-grade lecithins do not disperse in water, many modified or fractionated lecithins are water-dispersible, and they can be used to produce microemulsions. Standard-grade lecithin can be blended with other surfactants (e.g., ethoxylated monoglycerides) to produce synergistic emulsifier blends that are also effective in producing microemulsions. 

In the various applications, each type or group of products usually requires a selected asbestos fiber grade (or range of grades). Table 6 lists various types of chrysotile applications in relation to fiber grades (Quebec Standard grade system). 

In this way very pure products are obtainable the standard grade of white phosphorus is over 99 9 per cent pure and contains only the merest traces of sulphur and arsenic. It is extremely reactive chemically and it is said that an excise officer once found this out very much to his cost. When prowling round Albright s factory he wrapped a piece of the curious barley sugar or lemon rock in paper, and put it in his pocket and — lived to regret it. 

The sludge may be used in the production of nongranular monoammonium phosphate (MAP) which, in turn, is used as an intermediate in the production of compound fertilizers. Tliere is no standard grade for MAP... 

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