Hydrogen grades available

Table 1. Hydrogen Grades Available. (Units in ppm (mole/mole) unless otherwise stated)... 

Properties White or yellowish powder odorless almost tasteless. Decomposes at approximately 200C. Almost insoluble in water soluble in acids with formation of hydrogen peroxide. Available oxygen 22.2% (min 13.3% in technical grade). 

Three such polymer modifications designed to improve the service characteristics of NBR are now commercially available. These are the saturated (or hydrogenated) grades, the antioxidant bound types and the carboxylated grades. 

Rosins - These are abietie aeid resins obtained from wood sourees. There are several different types wood rosins obtained from the naptha extraetion of pine stumps, gum rosins obtained from the destruetive distillation of turpentine, and tall oil rosins obtained by the destruetive steam distillation of tall oil from the manufacture of paper. Rosins are widely used in the adhesive and sealant industry. In hot melts they oxidize and diseolor easily at high temperatures due to the imsaturation in the resin. Hydrogenated grades are available which have much better thermal stability. 

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. 

The tetrahydrofurfuryl alcohol available from the Quaker Oats Company, or the Practical grade from the Eastman Kodak Company, has been used. If the material a ailable does not hydrogenate satisfactorily, it may be purified by hydrogenation over Raney nickel at 150 /100-200 atmospheres pressure. A sample of good quality boils at 177-178°/740 mm. and does not become dark-colored when a few milliliters are shaken with 1 drop of concentrated sulfuric acid at room temperature. 

Commercially available hydrogen fluoride usually is not suitable for catalytic hydrogenation because of its sulfur dioxide content An oxidative treatment with manganese dioxide and distillation are needed for the preparation of hydrogena tion-grade hydrogen fluoride [d, 4]... 

Solutions of hydrogen sulfide, because of hydrogen-induced cracking. Grades of steel are available for certain ranges of pH and hydrogen sulfide partial pressure. 

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