Safety perchlorates

Existing knowledge on perchloric acid and its salts was reviewed extensively in 1960 in a monograph including the chapters Perchloric Acid Alkali Metal, Ammonium and Alkaline Earth Perchlorates Miscellaneous Perchlorates Manufacture of Perchloric Acid and Perchlorates Analytical Chemistry of Perchlorates Perchlorates in Explosives and Propellants Miscellaneous Uses of Perchlorates Safety Considerations in Handling Perchlorates [1], There is a shorter earlier review, with a detailed treatment of the potentially catastrophic acetic anhydride-acetic acid-perchloric acid system. The violently explosive properties of methyl, ethyl and lower alkyl perchlorate esters, and the likelihood of their formation in alcohol-perchloric acid systems, are stressed. The instability of diazonium perchlorates, some when damp, is discussed [2],... 

Perchlorate Safety Explosives, Ltd., patented an ammonium perchlorate explosive containing finely divided zinc and combustible materials. 

The precipitated acetyHde must be decomposed with hydrochloric acid after the titration as a safety measure. Concentrated solutions of silver nitrate or silver perchlorate form soluble complexes of silver acetyHde (89). Ammonia and hydrogen sulfide interfere with the silver nitrate method which is less... 

Warning of danger The perchloric acid-containing reagent should not be employed as a spray solution for reasons of safety. 

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)... 

Round Robin No 30 of the ICRPG Working Group on Analytical Chemistry Particle Size Analysis of Nominal 20- to 30-Micron Ammonium Perchlorate with the Mine Safety Appliances Analyzer", RK-TR-69-13 (1969) 40) R.A. Dobbins L.D. Strand, AIAA Joum 8, 1544 (1970) 41) R.W. Hutchinson, Use of... 

Levens, Safety Considerations in Handling Perchlorates in ibid, 187 14) F.A. Warren et al,... 

Thomas, R. N., Univ. Safety Assoc. Safety News, 1981, 15, 16-17 Failure of the product (0.5 g) to crystallise out from the aqueous DMF reaction liquor led to vacuum evaporation of the solution at 60-70°C. Dining evaporation the mixture exploded violently, shattering the fume cupboard sash of toughened glass. The product may well be thermally unstable, but reaction of DMF with excess warm perchloric acid, possibly in near-absence of water, may also have been involved. 

Attention is drawn to the hazards involved in the use of perchloric acid in a published method [1] for transesterification of triglycerides with methanol. Alternative acid catalysts and safety precautions are suggested [2],... 

Materials for a batch of ammonium perchlorate castable propellant were charged into a mechanical mixer. A metal spatula was left in accidentally, and the contents ignited when the mixer was started, owing to local friction caused by the spatula. A tool-listing safety procedure was instituted [1]. The literature on the kinetics of thermal decomposition has been reviewed critically [2],... 

Numbers 7 and 8 in Table 3.6 represent high hazard substances such as azides, peroxides, perchlorates, and nitro compounds. The handling of such materials requires extreme care and safety precautions. 

See also Borates Boric acid Sodium borates boron oxides, 4 246-249 boron oxides table,4 242t environmental concerns, 4 284—285 health and safety factors, 4 285-288 occurrence, 4 245—246 Boron perchlorates, 18 278 Boron phosphate, 4 242t, 283 Boron removal, from water, 14 418 Boron-stabilized carbanions, 13 660-661 Boron subhalides, 4 141 Boron suboxide, 4 242t Boron tribromide, 4 138 manufacture, 4 145—146 physical properties of, 4 139-140t, 325 reactions, 4 141 specifications, 4 147t uses of, 4 149 Boron trichloride, 4 138 manufacture, 4 145—146 physical properties of, 4 139-140t reactions, 4 141... 

Safety While we list safety last, safety must always be at the top of the list of considerations. For example, you should not even consider a method requiring perchloric acid digestion for sample preparation unless your facility has the appropriate quality fume hood. In Table 21.10, we have listed some of the many safety issues you need to evaluate. 

Open vessel digestion (HF HC104) for ceramics, glass, rocks, and soil These acids should completely dissolve most materials. HF removes the silica (as volatile SiF4), which reduces the total dissolved solid content and therefore reduces interferences, and C104 produces perchlorates, which are soluble (but explosive if dried out). The use of hydrofluoric and perchloric acids therefore has considerable safety risks and requires specialized fume hoods, handling equipment, and safety equipment. The hydrofluoric and perchloric acids are removed by a later evaporation stage unless the analytical instmment and safety considerations have been specially adapted. 

A Some of the most interesting and informative experiments in this field were done by Pepper s group and then at Keele and elsewhere with anhydrous perchloric acid as the initiator. It is therefore historically important that in the present super-cautious, safety conscious era, few, if any, workers are ever likely to follow Pepper s pioneering work with this hazardous material, to test the reproducibility of these classical findings. The same applies of course to our studies on the polymerisation of various 1,3-dioxacycloalkanes, most of which were also done with anhydrous HC104, see Chapter 7. There is no substitute for it, as every acid behaves differently and in particular the lazy worker s substitute aq. HC104 + acetic anydride, is a very different initiator system. 

Stepwise oxidation of organic snbstrates is often carried out with thainthreniumyl perchlorate. This oxidant will be encountered in many cases dnring the citing of materials in the following chapters. However, first, a safety warning shonld be pnt. It is a shock-sensitive solid that mnst be handled only on a small scale and with due care. 

When a thunderflash effect is required, a square of touch-paper is placed on the rear propellant surface inside the case at the opposite end to the choke, and a hairpin of safety fuse is placed inside the case in contact with the square of touch-paper. Some flash composition, based on potassium perchlorate, barium nitrate and aluminium, is then poured around the safety fuse and the head of the case is closed off with a pressing of clay or by simply being taped over. The all-important stick is... 

Bangers have ceased to be available to the general public in the UK since 1997, on safety grounds. More recently, the CEN (European Standardisation of Fireworks) has set maximum sound level requirements of 120dB at distances of 1, 8 and 15m for Category 1, 2 and 3 (nitrate or perchlorate based) flash bangers respectively. 

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