Sulfur-chlorate mixtures

Chemical testing is carried out in an approved laboratory because the firework must first be dismantled. Wet methods of analysis are applied that involve analytical grade reagents to detect, in particular, the presence of chlorates in admixture with elemental sulfur. Sulfur-chlorate mixtures are banned in the UK, and one use of sulfurless gunpowder is in fireworks where chlorates are also present. 

MATERIALS Small container such as a paper cup or tin can, rubber contraceptive or toy balloon, sugar-chlorate mixture (see section on incendiaries), concentrated sulfuric or nitric acid, nonelectric blasting cap. 

The effect of initiators (diluted sulfuric acid, chlorine dioxide, sulfur dioxide or disulfur dichloride) on ignition of mixtures of barium, lead or potassium chlorates with sulfur was examined [1] Presence of copper ion or metal (e.g. from a sieve) may also lead to explosion of such mixtures [2], A review of hazards of sulphur/chlorate mixtures in the firework industry has been published [3],... 

Many chlorate mixtures, particularly those which contain sulfur, sulfides, and picric acid, are extremely sensitive to blows and to friction. In the Street explosives, later called Cheddites because they were manufactured at Chedde in France, the chlorate is phlegmatized by means of castor oil, a substance which appears to have remarkable powers in this respect. The French Commission des Substances Explosives in 1897 commenced its first investigation of these explosives by a study of those which are listed below, and concluded 35 that their sensitivity to shock is... 

Derivatives of phenol or aniline can be oxidized to quinones, the yield and ease of oxidation depending on the substituents. If an amino or hydroxyl group is in the para position, the reaction proceeds readily, as illustrated by the synthesis of quinone from hydroquinone by oxidation with a sodium chlorate-vanadium pentoxide mixture (5>6%) or with chromic-sulfuric acid mixture (92%). A para halogen atom usually has a favorable effect. Any group in the para position is eliminated or oxidized. o-Quinones are usually prepared from the corresponding catechols. A survey of procedures for the synthesis of benzoquinones by oxidation has been made. ... 

Nitric acid-potassium dichromate - 738 Nitric acid-sodium chlorate - 738 Nitric acid-sodium nitrate - 738 Nitric acid-sulfuric acid mixtures (see Mixed acid) -693, 781... 

Other early match-like devices were based on the property of various combustible substances mixed with potassium chlorate to ignite when moistened with strong acid. More important was the property of chlorates to form mixtures with combustibles of low ignition point which were ignited by friction (John Walker, 1827). However, such matches containing essentially potassium chlorate, antimony sulfide, and later sulfur (lucifers), mbbed within a fold of glass powder-coated paper, were hard to initiate and unreHable. 

Various sulfides of the halogens are formed by direct combination of sulfur with fluorine, bromine, and chlorine. No evident reaction occurs with iodine instead, the elements remain as components of a mixture. Mixtures of sulfur and potassium chlorate, or sulfur and powdered zinc, are highly explosive. 

Potassium chlorate (or other metal halogenate) intimately mixed with arsenic, carbon, phosphorus, sulfur or other readily oxidised materials gives friction-, impact- and heat-sensitive mixtures which may explode violently [1], When potassium chlorate is moistened with a solution of phosphorus in carbon disulfide, it eventually explodes as the solvent evaporates and oxidation proceeds [2], Boron bums in molten chlorate with dazzling brilliance [3]. Mixtures of the chlorate and finely powdered sulfur containing over 20% of the latter will explode under a hammer-blow [4],... 

Addition of a drop of sulfuric acid to a mound of the chlorate-sugar mixture leads to ignition. 

The chemistry involved in this explosively unstable system is reviewed [1]. The mechanism of the trigger reactions that initiate the exothermic decomposition of chlorate-sulfur mixtures has been studied. Mixtures containing 1-30% of sulfur can decompose well below the m.p. of sulfur, and addition of sulfur dioxide, the suspected chemical trigger, causes immediate onset of the reaction [2], Autoignition of stoichiometric mixtures can be as low as 115°C, with frictional sensitivity at 5N, the lowest load the test apparatus permitted. Both were dependent upon the history of the sulphur used [3],... 

The sensitivity of chlorate-sulfur mixtures to initiation is increased by cobalt and its oxide, greatly so by copper nitride, copper sulfate, and extremely so by copper chlorate. Implications for manufacturing operations are discussed. 

The potential for explosive combustion of mixture of sodium chlorate-based herbicides with other combustible agricultural materials was determined. Initiation temperatures and maximum combustion temperatures were measured for mixtures of sodium (or potassium) chlorate with peat, powdered sulfur, sawdust, urotropine (hexamethylenetetramine), thiuram and other formulated materials. With many combinations, maximum temperature increases of 500-1000°C at rates of 400-12007s were recorded for 2 g samples. 

MRH Aluminium 10.71/33, iron 4.35/50, magnesium 10.88/40, manganese 5.06/50, sodium 5.56/55, phosphorus 7.32/25, sulfur 4.27/20 Mixtures of the chlorate with ammonium salts, powdered metals, phosphorus, silicon, sulfur or sulfides are readily ignited and potentially explosive [1], Residues of ammonium thiosulfate in a bulk road tanker contaminated the consignment of dry sodium chlorate subsequently loaded, and exothermic reaction occurred with gas evolution during several hours. Laboratory tests showed that such a mixture could be made to decompose explosively. A reaction mechanism is suggested. 

MRH Barium chlorate 5.06/83, calcium chlorate 5.61/77, potassium chlorate 6.07/76, sodium bromate 4.98/80, sodium chlorate 7.32/75, zinc chlorate 6.11/76 Dry finely divided mixtures of red (or white) phosphorus with chlorates, bromates or iodates of barium, calcium, magnesium, potassium, sodium or zinc will readily explode on initiation by friction, impact or heat. Fires have been caused by accidental contact in the pocket between the red phosphorus in the friction strip on safety-match boxes and potassium chlorate tablets. Addition of a little water to a mixture of white or red phosphorus and potassium iodate causes a violent or explosive reaction. Addition of a little of a solution of phosphorus in carbon disulfide to potassium chlorate causes an explosion when the solvent evaporates. The extreme danger of mixtures of red phosphorus (or sulfur) with chlorates was recognised in the UK some 50 years ago when unlicenced preparation of such mixtures was prohibited by Orders in Council. 

The self-ignition of sulfur with potassium chlorate or iodine(V) oxide at 145-160°C, and with potassium perchlorate at 385°C was studied using DTA [1], and combustion characterisitics of the mixtures were determined [2],... 

Tetraphosphorus trisulfide (P4S3) which is also called phosphorus sesquisulfide, can be obtained by heating a stoichiometric mixture of phosphorus and sulfur at 180 °C in an inert atmosphere. The compound (m.p. 174 °C) is soluble in toluene, carbon disulfide, and benzene, and it is used with potassium chlorate, sulfur, and lead dioxide in matches. 

Potassium chlorate Sulfur Formation of explosive mixture sensitive to shock and friction... 

In addition to being oxidants in contact with strong acids, metal chlorates liberate explosive chlorine dioxide gas. With cone, sulfuric acid, a violent explosion may occur unless effective cooling is used [1], Heating a moist mixture of a metal chlorate and a dibasic organic acid (tartaric or citric acid) liberates chlorine dioxide diluted with carbon dioxide [2],... 

Intimate mixtures of chlorates, bromates or iodates of barium, cadmium, calcium, magnesium, potassium, sodium or zinc, with finely divided aluminium, arsenic, copper carbon, phosphorus, sulfur hydrides of alkali- and alkaline earth-metals sulfides of antimony, arsenic, copper or tin metal cyanides, thiocyanates or impure manganese dioxide may react violently or explosively, either spontaneously (especially in presence of moisture) or on initiation by heat, friction, impact, sparks or addition of sulfuric acid [1], Mixtures of sodium or potassium chlorate with sulfur or phosphorus are rated as being exceptionally dangerous on frictional initiation. 

Amazingly, no such protocol existed in the UK before 1988, when it was difficult to prevent dangerous, imported fireworks from reaching the shop shelves. Thus, unsuspecting consumers could, in theory at least, purchase items containing prohibited mixtures of, say, sulfur and potassium chlorate and drop them onto the back seat of the family saloon where they could ignite without warning. 

As mentioned earlier, chlorates are also a major ingredient in various pyrotechnic formulations. Typically potassium chlorate is utilized in this capacity due to the more hygroscopic nature of the sodium analog. Mixed with powdered aluminum and/or sulfur, potassium chlorate produces a mixture commonly referred... 

Fire or explosion hazard may arise from the foUowing ammonia reactions Reaction with halogens produces nitrogen trihahdes which explode on heating its mixture with fluorine bursts into flame reacts with gold, silver, or mercury to form unstable fulminate-type shock-sensitive compounds similarly, shock-sensitive nitrides are formed when ammonia reacts with sulfur or certain metal chlorides, such as mercuric, or silver chloride liquid ammonia reacts violently with alkah metal chlorates and ferricyanides. 

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