Chemical general

In addition to the use of a melting point determination as a criterion of purity, an equally valuable application is for the identification of oiganic compounds. If the melting point is known within one degree, the major proportion of possible substances is immediately eliminated from consideration. The study of the general chemical properties of the compound and a mixed melting point determination (Section 1,17) will largely establish the identity of the compound. 

Other furan compounds, best derived from furfural, are of interest although commercial volumes are considerably less than those of furfural, furfuryl alcohol, furan, or tetrahydrofurfuryl alcohol. Some of these compounds are stiU in developmental stages. Apphcations include solvents, resin intermediates, synthetic mbber modifiers, therapeutic uses, as well as general chemical intermediates. 

There are no estabHshed specifications for the standard reference samples used in general chemical analysis. Many such substances, however, are analyzed and certified by the National Institute of Standards and Technology (NIST), formerly the National Bureau of Standards (NBS). Specific reference standards are required for many of the analyses included in the USP and NE standards for dmgs. 

Ammonium fluoroborate is both a condensed and vapor-phase flame retardant. It is available from M T Hatshaw, General Chemical Cotp., and Spectmm Chemical Cotp. 

Economic Aspects. In the United States fluoroboric acid is manufactured by Atotech USA, Inc., General Chemical, C.P. Chemical Co., Fidehty Chemical Products, and Chemtech Harstan. Research quantities of reagent grade are made by Advance Research Chemical Co., Johnson-Mathey, and Ozark-Mahoning Co. The price for 48% fluoroboric acid in tmcHoad quantities in 1993 was 2.13—2.25/kg (20). 

Chemicals, Atotech USA, Inc., and General Chemical. The lithium compound is available from Advance Research Chemicals, Cypms Foote Mineral, and FMC Lithium Corp. of America. Small amounts of other fluoroborates are sold by Alfa Inorganics, Inc. and O ark-Mahoning Co. Prices in 1993 for tmddoad quantities were NaBF, 4.95—6.25/kg KBF, 3.55/kg andNH BF 5.03—6.35/kg. 

Oyygen Dfluoride, Product Data Sheet, General Chemical Division, AUied Chemical Corp., Morristown, N.J. 

Pyrotechnics is based on the estabflshed principles of thermochemistry and the more general science of thermodynamics. There has been Httle work done on the kinetics of pyrotechnic reactions, largely due to the numerous chemical and nonchemical factors that affect the bum rate of a pyrotechnic mixture. Information on the fundamentals of pyrotechnics have been pubflshed in Russian (1) and English (2—6). Thermochemical data that ate useful in determining the energy outputs anticipated from pyrotechnic mixtures are contained in general chemical handbooks and more specialized pubHcations (7-9). 

The crystalline mineral silicates have been well characterized and their diversity of stmcture thoroughly presented (2). The stmctures of siHcate glasses and solutions can be investigated through potentiometric and dye adsorption studies, chemical derivatization and gas chromatography, and laser Raman, infrared (ftir), and Si Fourier transform nuclear magnetic resonance ( Si ft-nmr) spectroscopy. References 3—6 contain reviews of the general chemical and physical properties of siHcate materials. 

RTV Silicone Chemistry. There are two basic cure chemistries used by RTV sihcones the acetoxy-based and the alkoxy-based cure systems. Acetoxy-based RTV sihcones were first commercialized in the early 1960s (422,423). The general chemical reactions of these first-generation products are shown in Figure 8. 

Sodium nitrite. Product brochure, QsCllCl, General Chemical Corp., Parsippany, N.J., 1989. 

Economic Aspects. U.S. production of sodium metabisulfite is estimated to be well ia excess of 45,000 t, but statistics are confused by some commingling with sodium sulfite. The principal U.S. producers are Rhc ne-Poulenc and General Chemical. The price ia mid-1995 was 0.63/kg for anhydrous sodium bisulfite. 

Gmelins Handbuch derAnorganischen Chemie, 8th ed.. System No. 9, Part B2, Vedag Chemie, Weinheim/Bergstrasse, Germany, 1960, pp. 373—613. Sodium Sulfite, product brochure. General Chemical Co., Claymont, Del., 1993. 

Sodium Bisulfite, CHRIS Hazardous Chemical Data, Coast Guard, U.S. Dept, of Transportation, Washington, D.C., data sheet revised 1978. Treatment of Chromium Waste Eiquors, General Chemical Corp., Claymont, Del., 1989. 

Talc [14807-96-6], a naturally occurring mineral of the general chemical composition Mg2Si40 Q(0H)2, is a crystalline hydrous magnesium siUc ate belonging to the general mineral family of the layered siUcates. Other layered siUcates are kaolin, mica, and pyrophyUite (1). 

For special high strength appHcations, ie, up to 69 MPa (10,000 psi), special formulations of Pordand cement concretes have been developed. These ate based on the use of chemical and mineral admixtures. The typical mineral admixtures ate fumed siUca and other po22olanics. The chemical admixtures ate generally chemicals termed supetplastici2ets that allow very low water to cement ratios, ie, between 0.4 and 0.25, and reduce the amount of water needed to provide plasticity or dow to the concrete. PubHc works appHcations take just under 32% of the total Pordand cement market streets and highways represent 68% of this usage, and water and waste account for 23%. 

Refractories. Its low coefficient of expansion, high thermal conductivity, and general chemical and physical stabihty make sihcon carbide a valuable material for refractory use. Suitable apphcations for sihcon carbide refractory shapes include boiler furnace walls, checker bricks, mufflers, kiln furniture, furnace skid rails, trays for zinc purification plants, etc (see Refractories). 

Polyamide Imides. Polyamide imides (PAIs) are formed from the condensation of trimellitic anhydride and aromatic diamines (33). The polymer is called amide—imide because the polymer chain comprises amide linkages alternating with imide linkages, with the general chemical stmcture ... 

Nylon is similar ia its general chemical stmcture to the natural fiber wool, and therefore all the previously described processes for wool are appHcable to dyeiag nylon with acid, metallised, and other dyes. There are, however, significant differences. Nylon is synthetic, it has defined chemical stmcture depending on the manufactufing process, and it is hydrophobic (see Fibers, POLYAMIDES). 

---