Safety shields

Safety glass Safety helmets Safety match Safety regulations Safety shields Safety windshields Safflorite Safflower... 

Initially, DADC polymers were used in military aircraft for windows of fuel and deicer-fluid gauges and in glass-fiber laminates for wing reinforcements of B-17 bombers. Usage in impact-resistant, lightweight eyewear lenses has grown rapidly and is now the principal appHcation. Other uses include safety shields, filters for photographic and electronic equipment, transparent enclosures, equipment for office, laboratory, and hospital use, and for detection of nuclear radiation. 

Because of the dangerous nature of hydrazine, a safety shield should always be in place during this reaction. 

Vanadyl trichloride (VOCI3) [7727-18-6] M 173.3, m-79.5°, b 124.5-125.5°/744mm, 127.16°/760mm, d 1.854, d 1.811. Should be lemon yellow in colour. If red it may contain VCI4 and CI2. Fractionally distil and then redistil over metallic Na but be careful to leave some residue because the residue can become EXPLOSIVE in the presence of the metal USE A SAFETY SHIELD and avoid contact with moisture. It readily hydrolyses to vanadic acid and HCl. Store in a tightly closed container or in sealed ampoules under N2. [Inorg Synth 1 106 1939, 4 80 1953.]... 

Caution Addition of 0 5 cm pieces of sodium metal to methanol or ethanol must be done in a chemical hood and behind a safety shield. Addition should be slow to minimize evaporation loss of methanol or ethanol. No flames or burner should be permitted in the area. Disposal of sodium metal must be earned out in someone s presence. 

Caution All reactions with organic peroxides should be conducted behind a safety shield, since peroxides occasionally explode. 

The following operations are carried out in a hood behind a safety shield ... 

Benzene (80 ml) is placed in a suitable pressure vessel (soft drink bottle or hydrogenation bottle) and chilled to 5°. The bottle is weighed, and a gas dispersion tube connected to a cylinder of butadiene is immersed in the benzene. Butadiene is introduced into the flask with continued cooling until a total of 32 g has been transferred. Pulverized maleic anhydride (50 g) is added to the bottle, which is then capped or stoppered with a stopper wired in place. The bottle is allowed to stand at room temperature for 12 hours, then is heated (behind a safety shield) to 100° for 5 hours. The bottle is cooled, then opened, and the contents are transferred to an Erlenmeyer flask. The mixture is heated to boiling, and petroleum ether is added until there is a slight turbidity. After cooling, the product is collected, mp 101-103° (yield 90%). 

Polycarbonates are used in a variety of articles such as laboratory safety shields, street light globes, and safety helmets. The maximum usage temperature for polycarbonate objects is 125°C. 

Caution This reaction should he carried out in an explosion-proof room behind a safety shield because it involves a glass vessel under pressure. 

All experimental manipulations with the reaction vessel while it is sealed and under pressure should be carried out behind a safety shield. 

The polymer can be conveniently removed by filling the flask two-thirds full with concentrated nitric acid and warming gently on a steam bath in a hood behind a safety shield. 

Pure hydrazoic acid in a condensed state has been reported in several instances to explode violently without apparent inducement, but explosions during Schmidt reactions do not seem to have been observed. Nevertheless, it is recommended that this reaction be carried out behind a safety shield. 

Perchjorate, FNH3+C104 , mp 104-05° with decompn prepd by addn of N-iso-Pi-N-fluoro-ure thane to a so In of perchloric acid in chlf (work must be done behind a good safety shield as compds are expl) (Ref 5)... 

Caution The nitrating mixture consisting of fuming nitric acid and acetic anhydride is an extremely active one, and combinations of it and organic materials are potentially explosive. The nitration should be carried out behind adequate safety shields. Acetone cyanohydrin nitrate is moderately explosive (Note 6) and all operations with it, but particularly its distillation, should be carried out behind safely shields. 

Acetone cyanohydrin nitrate should be regarded as a moderately explosive material and should be handled carefully and distilled behind a safety shield. For purposes of comparison, the drop-weight sensitivities on the Olin-Mathieson drop-weight tester of three materials are propyl nitrate, 10 kg.-cm. acetone cyanohydrin nitrate, 40 kg.-cm. nitromethane, 60 kg.-cm. 

CautionI All reactions in which 50% or more concentrated hydrogen peroxide is employed must he conducted behind a safety shield. Beakers are recommended as reaction vessels to permit rapid escape of gas and avoidance of pressure build-up in the event of a rapid decomposition. 

Caution Diazomalonic esters are toxic and potentially explosive. They must be handled with care. This preparation should be carried out in a well-ventilated hood, and the distillation of di-tcit-butyl diazomalonate should be conducted behind a safety shield. 

Caution Potassium is highly reactive. Although it may be handled safely in air if it is covered with a hydrocarbon solvent such as heptane or mineral oil, it will spark and ignite flammable organic vapors on contact with water. The magnesium formed in this reaction is highly reactive and pyrophoric (Note 1). Accordingly, Parts C and D of this procedure should be carried out behind a safety shield. 

Caution This distillation should be carried out behind a safety shield. Thenyl bromide is a powerful lachrymator, and some individuals may develop extensive irritation of the skin upon exposure to its vapors. The checkers observed boiling points of 78-82°/2 mm. and 80-85°/3 mm. 

Methyl diazoacetate was obtained according to a procedure for ethyl diazoacetate (Searle, N.E. Org. Synth., Coll. Vol. A/1963, 42). Although the experiments were usually performed with distilled methyl diazoacetate (bp 43°C at 25 mm, bath temperature below 60°C) without any problems, the cyclopropanation reaction described works equally well with undistilled diazo compound. If distilled diazo compound is desired, the submitters have stated that "a spatula of K2CO3 Is added to the crude diazo ester to trap traces of add and then distill behind a safety shield . The checkers did not evaluate this aspect of the procedure. 

Crude methyl diazoacetate contains up to 20% of the solvent dichloromethane. which has to be taken into account when calculating the stoichiometry. The checkers had no problems in preparing, handling, antf using undistilled methyl diazoacetate however, it must be emphasized that this compound is a potential explosive and all operations should be performed behind an effident safety shield. 

Ethers should be stored in metal containers. Only small quantities should be purchased. Ethers should not be kept over 6 months. Containers should be labeled and dated upon receipt, and opened containers should be discarded after 3 months. All work with ethers should be done behind safety shields. Inhibitors should be used whenever possible. 

This distillation has been conducted with the usual precautions (safety glasses, safety shield) with no explosions up to the present time. 

Many useful articles such as safety goggles, safety shields, telephone parts and machinery housings can be made from... 

The pot temperature should not be allowed to rise above 70° (the submitters used a hot-water bath at 75°), as a fume-off which may proceed with explosive violence is likely to occur. A nitrogen bubbler may be used to eliminate bumping. The distillation should be carried out behind a safety shield. 

No air should be allowed to come in contact with the hot pot liquid during the distillation, for an exothermic reaction may occur at best this may fill the apparatus with tarry material and the room with noxious fumes at "worst, pressure built up may destroy all or part of the apparatus. As a precaution, this distillation should be carried out behind a safety shield. 

C. Crotyl diazoacetate. A solution of 10.0 g. (0.038 mole) of the />-toluenesulfonylhydrazone of glyoxylic acid chloride in 100 ml. of methylene chloride is cooled in an ice bath. Crotyl alcohol (2.80 g. or 0.038 mole) (Note 7) is added to this cold solution, and then a solution of 7.80 g. (0.077 mole) of redistilled triethyl-amine (b.p. 88.5-90.5°) in 25 ml. of methylene chloride is added to the cold reaction mixture dropwise and with stirring over a 20-minute period. During the addition a yellow color develops in the reaction mixture and some solid separates near the end of the addition period. The resulting mixture is stirred at 0° for 1 hour and then the solvent is removed at 25° under reduced pressure with a rotary evaporator. A solution of the residual dark orange liquid in approximately 200 ml. of benzene is thoroughly mixed with 100 g. of Florisil (Note 8) and then filtered. The residual Florisil, which has adsorbed the bulk of the dark colored by-products, is washed with two or three additional portions of benzene of such size that the total volume of the combined benzene filtrates is 400-500 ml. This yellow benzene solution of the diazoester is concentrated under reduced pressure at 25° with a rotary evaporator, and the residual yellow liquid is distilled under reduced pressure. (Caution This distillation should be conducted in a hood behind a safety shield) (Note 9). The diazo ester is collected as 2.20-2.94 g. (42-55%) of yellow liquid, b.p. 30-33° (0.15 mm.), n T) 1.4853 - 1.4856 (Note 10). 

Although this distillation has been performed repeatedly without incident, the product is potentially explosive and the operator should take suitable precautions including surrounding the distillation apparatus with a hood and a safety shield and wearing an effective face shield. 

The distillation is not carried to completion because of the resulting danger of explosion. It is carried out with the usual safety precautions (safety shield), although no explosion has yet occurred. 

Safety precautions Before the experiment is carried out, Sect. 2.2.5 must be read as well as the material safety sheets (MSDS) for all chemicals and products used. Due to the high temperature of the oil bath needed in this experiment, special care has to be taken and one has to work in a closed hood. In addition, a safety shield is required when working under high vacuum. 

The crude diazo ketone is first obtained as a viscous yellow oil, which slowly solidifies under high vacuum. The checkers always handled the solid material behind a safety shield. 

Caution. The residues left behind in the reaction flask should be cautiously destroyed under nitrogen in the hood, behind a safety shield, by the slow addition of 20% 1-pentanol-hexane solution until no further reaction is visible. 

Note Particular care should be exercised in handling test items after the jolt jumble tests a safety shield should be used. The articles may become armed or the expl chge may have sifted out. In these cases, a slight jar may initiate a defective fuze. The jolt test is always run first. Total time for both tests is ca 5 /i hrs... 

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