Cooling protection

Geraniol [106-24-1] M 154.3, b 230 , d 0.879, n 1.4766. Purified by ascending chromatography or by thin layer chromatography on plates of kieselguhr G with acetone/water/liquid paraffin (130 70 1) as solvent system. Hexane/ethyl acetate (1 4) is also suitable. Also purified by GLC on a silicone-treated column of Carbowax 20M (10%) on Chromosorb W (60-80 mesh). [Porter Pure Appl Chem 20 499 7969.] Stored in full, tightly sealed containers in the cool, protected from light. 

Storage in closed containers, cool, protected from light. 

Alternate work-up The filtered tetrahydroturan solution is concentrated under reduced pressure (20°C, 50 mm) to a volume of 80 mL. Dry hexane (KF < 50 pg/mL, 600 mL) is slowly added with stirring. The product should begin to crystallize during the addition seed if necessary. The mixture is stirred at 20-25°C for 1 hr, then filtered. The cake is washed with dry hexane (2 x 25 mL). Filtration is performed in an enclosed, medium-frit Schlenk funnel, under an atmosphere of nitrogen (with careful exclusion of moisture). The cake is dried under reduced pressure (30°C, < 100 mm) for 2 hr to yield 70.5 g (95%) as a free-flowing white crystalline solid, mp 51.5-52°C. The product should be stored cool, protected from moisture. By microanalysis, the product contains 1-4 wt% of triethylammonium hydrochloride. It is also possible to concentrate the THF to precipitate the product as a white solid. 

Polyester resin and initiator components should both be stored in cool, protected areas. 

It has been shown previously that a decrease in temperature from 20° to 0°C induces the transition D —> 2 R in aqueous solutions, with a transition pK of 7.7. The dissociation is fully reversible by warming. On the other hand, in the presence of 50% by volume of ethylene glycol there was no modification of the above picture and the transition pK was 7.7 at the same concentration in lactoglobulin (Hui Bon Hoa et al., 1973). A decrease in temperature from 20° to — 40°C shifts this pK value progressively (Table XXVI). The pK change between 20 and — 40°C amounts to 1.85 unit. Thus cooling protects the dimer in the pH range where it is dissociated at room temperature. Between... 

Definition Volatile oil obtained from leaves and tops of Melissa officinalis Properties Yel. to yish.-grn. liq. sol. in alcohol pract. Insol. In water dens. 0.89-0.925 (15/15 C) Storage Keep well closed, cool protect from light Uses Natural flavoring agent in foods and pharmaceuticals... 

HMiS Health 2, Flammability 2, Reactivity 0 Storage Keep well closed, cool, protected from light... 

Toxicoiogy TDLo (oral, mouse, 40 wks intermittent) 67 g/kg skin irritant inh. or frequent contact may cause headache, dizziness, shortness of breath, allergic reaction in hypersensitive persons questionable carcinogen experimental neoplastigen TSCA listed Hazardous Decomp. Prods. Heated to decomp., emits acrid smoke and irritating fumes HMiS Health 0, Flammability 2, Reactivity 0 Storage Keep well closed, cool, protected from light... 

Core cooling (protects the integrity of the fuel cladding or structure) ... 

To approximately 0-2 g acetomenaphthone add 15 ml of glacial acetic acid and 15 ml of dilute hydrochloric acid and boil under reflux condenser for at least fifteen minutes. Cool, protecting against aerial oxidation, and titrate with 0 05N ceric ammonium sulphate using 01 ml of o-phenanthroline-ferrous complex as indicator. Carry out a blank determination using exactly the same amount of indicator. 1 ml 0-05N = 0-006457 g. 

The basin A is then gently heated by a small Bunsen flame, which should be carefully protected from side draughts by screens, so that the material in A receives a steady uniform supply of heat. The material vaporises, and the vapour passes up through the holes into the cold funnel C. Here it cools and condenses as fine crystals on the upper surface of the paper B and on the walls of C. When almost the whole of the material in A has vaporised, the heating is stopped and the pure sublimed material collected. In using such an apparatus, it is clearly necessary to adjust the supply of heat so that the crude material in A is being steadily vaporised, while the funnel C does not become more than luke warm. 

Method B. In a 500 ml. round-bottomed flask, provided with a reflux condenser protected by a cotton wool (or calcium chloride) drying tube, place 59 g. of succinic acid and 102 g. (94-5 ml.) of redistilled acetic anhydride. Reflux the mixture gently on a water bath with occasional shaking until a clear solution is obtamed ca. 1 hour), and then for a further hour to ensure the completeness of the reaction. Remove the complete assembly from the water bath, allow it to cool (observe the formation of crystals), and finally cool in ice. Collect the succinic anhydride as in Method A. The yield is 45 g., m.p. 119-120°. 

The special reducing agent (a solution containing cupro-ammonia ions) is first prepared. Dissolve 63 g. of crystallised copper sulphate in 250 ml. of water in a 1-Utre heaker, add 100 ml. of concentrated ammonium hydroxide solution (sp. gr. 0-88), and cool the solution to 10°. Dissolve 17 8 g. of hydroxylammonium chloride or 21 g. of hydroxylammonium sulphate in 60 ml. of water, cool to 10°, and add 42 -5 ml. of QN sodium hydroxide solution if the resulting solution of tydroxylamine is not clear, filter it at the pump. Without delay add the hydroxylamine solution, with stirring, to the ammoniacal cupric sulphate solution. Reduction occurs at once, a gas is evolved, and the solution assumes a pale blue colour. Protect the reducing agent from the air if it is not used immediately. 

Dihydroxyacetophenone. Finely powder a mixture of 40 g. of dry hydroquinone diacetate (1) and 87 g. of anhydrous aluminium chloride in a glass mortar and introduce it into a 500 ml. round-bottomed flask, fitted with an air condenser protected by a calcium chloride tube and connected to a gas absorption trap (Fig. II, 8, 1). Immerse the flask in an oil bath and heat slowly so that the temperature reaches 110-120° at the end of about 30 minutes the evolution of hydrogen chloride then hegins. Raise the temperature slowly to 160-165° and maintain this temperature for 3 hours. Remove the flask from the oil bath and allow to cool. Add 280 g. of crushed ice followed by 20 ml. of concentrated hydrochloric acid in order to decompose the excess of aluminium chloride. Filter the resulting solid with suction and wash it with two 80 ml. portions of cold water. Recrystallise the crude product from 200 ml. of 95 per cent, ethanol. The 3 ield of pure 2 5-dihydroxyacetophenone, m.p. 202-203°, is 23 g. 

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