Browning source

Figure 9-26 Reduction of Ortho-Quinone by Ascorbic Acid During Enzymic Browning. Source From M.L. Liao and RA. Seib, Selected Reactions of L-Ascorbic Acid Related to Foods, Food Technol., Vol. 41, no. 11, pp. 104-107, 1987.

Kekul s succinic and pyrotartaric acid, according to Crum Brown. Source Crum Brown,... 

A complex graphic formula by Frankland and Duppa, after Crum Brown. Source Frankland and Duppa, Journal of the Chemical Society 20 (1867) 111. 

Catalysis by charcoal yields a yellow-brown source for trianunines ... 

FIGURE 28 2 Molecular modeling—1953 style James Watson (left) and Francis Crick (right) with their DNA model A Barrington Brown/Science Source Photo Researchers Inc... 

K. H. Brown, Proc. Soc. Photo-Opt. Instr. Eng. 2438, 33 (1995). A good source of information on the new exposure technologies can be found in the Proceedings of the International Conference on Electron, Ion and Photon Beam Technology and Nanofabrication, pubhshed annuaUy in Issue 6 of the Journal of Vacuum Science and Technology B. 

The brown crystalline manganese(III) acetate dihydrate is of considerable commercial importance because it is often used as the source material for other trivalent manganese compounds. It can be made by oxidation of manganese(II) acetate using chlorine or potassium permanganate, or by reaction of manganese(II) nitrate and acetic anhydride. 

Bay Oil. Steam distillation of the leaves of the tree Pimenta racemosa (Mill) which is indigenous to certain islands of the West Indies, particularly Dominica and Puerto Rico, is called bay or bay leaf oil. The same source was used in the past to produce Bay Rum in which mm was distilled over the leaves. Bay oil [8006-78-8] is a yellowish to dark brown mobile Hquid with a fresh-spicy, sometimes medicinal odor with a lasting sweet-balsamic undertone. The oil finds extensive use in hair tonics, after-shave lotions as well as other men s-type fragrances. There is Htde or no use by the flavor industry. The range of components for a number of bay leaf oils is shown in Table 25 (66). 

Naturally occurring cadmium compounds are limited to the rare minerals, greenockite [1317-58 ] CdS, and otavite (1), an oxycarbonate, but neither is an economically important source of cadmium metal or its compounds. Instead, cadmium compounds are more usually derived from metallic cadmium [7440-43-9] which is produced as a by-product of lead—2inc smelting or electrolysis (see Cadmiumand cadmium alloys). Typically, this cadmium metal is burnt as a vapor, to produce the brown-black cadmium oxide [1306-19-0], CdO, which then acts as a convenient starting material for most of the economically important compounds. 

Paprika oleoresin (EEC No. E 160c) is the combination of davor and color principles obtained by extracting paprika with any one or a combination of approved solvents acetone, ethyl alcohol, ethylene dichloride, hexane, isopropyl alcohol, methyl alcohol, methylene chloride, and trichloroethylene. Depending on their source, paprika oleoresins are brown—red, slightly viscous, homogeneous Hquids, pourable at room temperature, and containing 2—5% sediment. 

FIG. 5-12 Variation of absorptivity with temperature of radiation source. (1) Slate composition roofing. (2) Linoleum, red brown. (3) Asbestos slate. (4) Soft rubber, gray. (5) Concrete. (6) Porcelain. (7) Vitreous enamel, white. (8) Red brick. (9) Cork. (10) White dutch tile. (11) White chamotte. (12) MgO, evaporated. (13) Anodized aluminum. (14) Aluminum paint. (15) Polished aluminum. (16) Graphite. The two dashed lines bound the limits of data on gray paving brick, asbestos paper, wood, various cloths, plaster of parts, lithopone, and paper. To convert degrees Ranldne to kelvins, multiply by (5.556)(10 ). 

Exothermic Decompositions These decompositions are nearly always irreversible. Sohds with such behavior include oxygen-containing salts and such nitrogen compounds as azides and metal styphnates. When several gaseous products are formed, reversal would require an unlikely complex of reactions. Commercial interest in such materials is more in their storage properties than as a source of desirable products, although ammonium nitrate is an important explosive. A few typical exampes will be cited to indicate the ranges of reaction conditions. They are taken from the review by Brown et al. ( Reactions in the Solid State, in Bamford and Tipper, Comprehensive Chemical Kinetics, vol. 22, Elsevier, 1980). 

Alkaloids of Pot Curare. This variety of curare is a dark brown, comparatively dry extract. According to Boehm, it contains protocurine, colourless hair-like needles, m.p. 306° (dec.), a base of low toxicity and yielding crystalline salts. A second alkaloid of similar type is protocuridine prisms, m.p. 274-6°, sparingly soluble in all ordinary solvents. The poisonous constituent is protocurarine, a red powder, easily soluble in water, and giving characteristic colour reactions with nitric acid and with oxidising agents in sulphuric acid, this latter reaction indicating a Strychnos spp. as a possible botanical source. 

---