Cold hght

To obtain crystalline perbenzoic acid, dry the moist chloroform solution with a little anhydrous sodium or magnesium sulphate for an hour, filter, and wash the desiccant with a little dry chloroform. Remove the chloroform under reduced pressure at the ordinary temperature whilst carbon dioxide is introduced through a capillary tube. Dry the white or pale yellow residue for several hours at 30-35° under 10 mm. pressure. The yield of crystalline perbenzoic acid, m.p. about 42°, which is contaminated with a little benzoic acid, is 22 g. It is moderately stable when kept in the dark in a cold place it is very soluble in chloroform, ethyl acetate and ether, but only shghtly soluble in cold water and in cold hght petroleum. 

Azlactone of a-acetylaminocinnamic acid. Warm a mixture of 29 g. of acetylglycine, 39-5 g. (37 -5 ml.) of redistilled benzaldehyde (Section IV,115), 15 g. of anhydrous sodium acetate and 67 g. (62 ml.) of acetic anhydride (95 per cent.) in a 500 ml. conical flask (equipped with a reflux condenser) on a water bath with occasional stirring until solution is complete (10-20 minutes). Boil the resulting solution for 1 hour, cool and leave in a refrigerator overnight. Stir the sohd mass of yellow crystals with 60 ml. of cold water, transfer to a Buchner funnel and wash well with cold water. (If the odour of benzaldehyde is stih apparent, wash with a little ether.) Recrystallise from carbon tetrachloride or from ethyl acetate-hght petroleum. The yield of azlactone, m.p. 150°, is 35 g. 

P-Ketoester Chelates. p-Ketoesters react in a fashion similar to the p-diketones. TYZOR DC [27858-32-8] is the hght-yeUow Hquid from TYZOR TPT and two moles of ethyl acetoacetate (eaa) after removal of the isopropyl alcohol. TYZOR BEAT, the bis-ethylacetoacetate [20753-28-0] derived from the tetra- -butyl titanate, and TYZOR IBAY [83877-91-2] the isobutoxy analogue, perform similarly to TYZOR DC. Both, however, have better cold-storage stabiHty. 

Re(0)Cl3(PPh3)2 (10 g, 0.011 mol) is placed in a 500-mL round-bottomed flask in benzene (250 mL) with a magnetic stirring bar. Concentrated hydrochloric acid (Fisher 44 mL, 12 M) is added slowly to the suspension followed by dimethylsulfoxide (Fisher 10 g, 0.13 mol). The suspension is stirred for 5 days closed to the atmosphere. The resulting hght green solid is collected by suction filtration, and then washed with (2 x 30 mL) acetone and then with cold dichloromethane (2 x 30 mL). After drying in air, the yield is 7.5 g (95%). 

Fohc acid (1) is found as yellow, thin platelets which chat above 250°C. The uv spectmm of L-folic acid at pH 13 shows absorptions at A = 256 nm (e = 30,000), 282 nm (e = 26,000), and 365 nm (e = 9800). Folic acid has a specific rotation of [a](( = +19.9° (c = 1, 0.1 Af NaOH). Solutions of fohc acid ate stable at room temperature and in the absence of hght. It is shghdy soluble in aqueous alkah hydroxides and carbonates but is insoluble in cold water, acetone, and chloioform. Table 3 hsts some physical piopeities of selected fohc acid derivatives. 

Dibenzotellurophene. Tellurium powder (6 g, 47 mmol) and dibenzothiophene S.S -diox-ide (8 g, 37 mmol) are mixed thoroughly, the mixture is carefully heated under an atmosphere of carbon dioxide until evolution of sulphur dioxide commences, and the temperature is then regulated to achieve a steady evolution of sulphur dioxide. From time to time the sublimed dibenzothiophene dioxide is melted and allowed to flow back into the reaction mixture. After 36 h, the mixture is cooled to 20°C and extracted with boiling acetone. The extract is evaporated to dryness, the solid residue is washed several times with cold ethanol, and the washings are collected and evaporated. The residue is steam distilled and the product is recrystaUized from hght petroleum ether. Yield 1.0 g (10%) m.p. 93°C. 

Cold rolled steel This material is intended for hght duty finer applications only. However, carefully prepared and treated to resist corrosion, by a coating of epoxy, this is the most common... 

Variamine Blue RT [4-(phenylamino)benzenediazonium sulfate (1 1)] [4477-28-5] M 293.3, m 120°(dec), Cl 37240, Amax 377 nm. Dissolve lOg of the dye in 100ml of hot water. Sodium dithionite (0.4g) is then added, followed by active carbon (1.5g) and is filtered hot. To the colomless or shghtly yellow filtrate a solution of saturated NaCl is added, and the mixture is cooled. The needles are filtered off, washed with cold water, dried at room temperature, and stored in a dark bottle (hght sensitive). [Anderson Steedly J Am Chem Soc 76 5144 1954, Eidey Chem Analyst AH 106 1959, Beilstein 16 H 602,161371,16 II307,16 HI 575.]... 

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