Drum compounds

The application of this reaction leads to the formation of a soluble drum compound, [n-BuSn C CCsHg] g CgHg, 1, Figure 2, containing cyclopentane units, and the formation of an unusual ladder compound, [(n-BuSn(0)02CPh)2 n-BuSn(Cl) (C CPh)2]2> 2> Figure 3 (4). 

Other than the chloro derivative, 2, the drum and ladder compounds are prepared in high yield, > 70%. All are soluble in organic solvents and show characteristic infrared spectra. The drum compounds and A exhibit a symmetrical doublet for the carboxylate stretching frequency, Vqqq, centered near 1550 cm 1 and a single Sn-0 stretch, v Q, near 600 cm-1. In contrast, the open-drum structures, 2 and 3, show an unsymmetrical vcoo doublet in the same region as that for the drums and the presence of two Sn-0 stretches near 600 cm. ... 

The drum compounds are thermally quite stable. For example, the cyclopentane carboxylic acid drum, 3, was heated at 300°C for 3 h in vacuum. The material obtained was soluble in CDCI3, and Sn NMR showed a single line at -A91.A ppm, compared to the starting material -A85.8. The shift is presumably due to loss of solvent molecules present in the crystal in the starting material. 

Although drum compounds are the must ubiquitous forms found in monoorganotin carboxylates, hexanuclear open-chain ladder compounds (Figure 2.4.10(a) and (b)) and trinuclear compounds (Figure 2.4.10(c)) are also found in some instances. The hexanuclear ladders can be converted to drums by a controlled hydrolysis. ... 

Figure 2.4.9 Schematic representation of the carboxylate ligands In the drum compounds containing the porphyrin or buckminister fullerene periphery...

Other routes for hydroxybenzaldehydes are the electrolytic or catalytic reduction of hydroxybenzoic acids (65,66) and the electrolytic or catalytic oxidation of cresols (67,68). (see Salicylic acid and related compounds). Sahcylaldehyde is available in drums and bulk quantities. The normal specification is a freezing point minimum of 1.4°C. 4-Hydroxybenzaldehyde is available in fiber dmms, and has a normal specification requirement of a 114°C initial melting point. More refined analytical methods are used where the appHcation requires more stringent specifications. 

Platform scale, manual cutoff 1 Drum 55 gal 208L 6-ply fiber (300 Ih) Lever-locked steel cover Cleaning compound 45 721 -20 to -1-80 mesh... 

The third process for cross-linking is the Sioplas process developed by Dow. The first stage of this involves the grafting of an easily hydrolysable trialkoxyvinylsilane onto the polyethylene chain, the site activation having been achieved with the aid of a small amount of peroxide. The compound is then extruded onto the wire, which is collected on a drum. The drum is then exposed to hot water, or, more commonly, low-pressure steam. The water hydrolyses the alkoxy groups, which then condense to form a siloxane cross-link. ... 

The design of any building or outside compound for the storage of chemicals in packages (e.g. drums, cylinders, sacks) will depend upon their hazardous characteristics (pages 228, 248 and 272). 

Certain refinery wastewater streams are treated separately, prior to the wastewater treatment plant, to remove contaminants that would not easily be treated after mixing with other wastewater. One such waste stream is the sour water drained from distillation reflux drums. Sour water contains dissolved hydrogen sulfide and other organic sulfur compounds and ammonia which are stripped in a tower with gas or steam before being discharged to the wastewater treatment plant. 

In a typical gas oil design, the lighter products overhead from the quench tower/primary fractionator are compressed to 210 psi, and cooled to about 100°F. Some Q plus material is recovered from the compressor knockout drums. The gases are ethanolamine and caustic washed to remove acid gases sulfur compounds and carbon dioxide, and then desiccant dried to remove last traces of water. This is to prevent ice and hydrate formation in the low temperamre section downstream. 

World production of I2 in 1992 approached 15 000 tonnes, the dominant producers being Japan 41%, Chile 40%, USA 10% and the former Soviet Union 9%. Crude iodine is packed in double polythene-lined fibre drums of 10-50-kg capacity. Resublimed iodine is transported in lined fibre drums (11.3 kg) or in bottles containing 0.11, 0.45 or 2.26 kg. The price of I2 has traditionally fluctuated wildly. Thus, because of acute over-supply in 1990 the price for I2 peaked at 22/kg in 1988, falling to 12/kg in 1990 and 9.50/kg in 1992. Unlike CI2 and Br2, iodine has no predominant commercial outlet. About 50% is incorporated into a wide variety of organic compounds and about 15% each is accounted for as resublimed iodine, KI, and other inorganics. The end uses include catalysts for synthetic rubber manufacture, animal- and fowl-feed supplements. 

Trichloroethylene containing traces of water was stored in a metallic drum. After a while the compound suddenly decomposed (or polymerised). 

The results of this situation can be readily foreseen. A requisition for a specific item is occasionally filled with an item which, at first glance, appears to be the one requested but, actually, was formulated for a different purpose and is either inadequate or dangerous to use for the intended purpose. A specific example of the hazards inherent in this situation may be found in the case of insecticide space spray composed of 1% DDT, 0.1% pyrethrins, or 2.5% thiocyanate in deodorized kerosene and 5% residual-effect DDT, both of which are issued in 5-gallon steel drums. Obviously, if a requisition for residual-effect DDT were to be filled with space spray, the application of the solution as a residual-effect compound w ould be of little or no value. Under some conditions, when stocks have been exposed to such adverse weather conditions that all gross identifying marks have been removed from the containers, the assumption has been made by the untrained native laborers that all unidentifiable cans of the same size contained the same material. Were it possible to have just one insecticide for all military purposes, such a situation could easily be avoided. 

The "unfolded-drum" or "ladder" compound 2 has crystallographic symmetry. This corresponds to the idealized molecular symmetry and, therefore, there are three chemically inequivalent types of Sn atoms in the molecule, although all are hexacoordinated. The oxygen atoms in the open form can be subdivided into two types, as in the case of the drum molecule tricoordinate framework oxygen atoms and the dicoordinate oxygen atoms of the bridging carboxylate ligands. 

Disposal of a benzene solution of phosphoryl chloride into a waste drum containing carbon disulfide (and other solvents) caused an instantaneous reaction, with evolution of (probably) hydrogen chloride. Presence of a hydroxylic compound seems likely. 

Inorganic solid wastes, particularly those containing toxic metals and toxic metal compounds, used Raney nickel, manganese dioxide, etc. should be placed in glass bottles or lined fiber drums, sealed, properly labeled, and arrangements made for disposal in a secure landfill. Used mercury is particularly pernicious and small amounts should first be amalgamated with zinc or combined with excess sulfur to solidify the material. 

Rubber in the form of fine threads produced by vulcanising a thin sheet of rubber compound, winding it on a drum and slitting it to the required size by revolving the drum against a number of sharp, wetted knives which revolve at high speed. Cyclised Rubber... 

Copper sulfate is used to control protozoan fish ectoparasites including Ichthyopthirius, Tri-chodina, and Costia. The effectiveness of the treatment diminishes with increasing total alkalinity and total hardness of the water (Straus and Tucker 1993). Copper compounds now used to control protozoan parasites of cultured red drum (Sciaenops ocellatus) include copper sulfate, copper sulfate plus citric acid, and chelated copper compounds (forms of copper bound by sequestering agents, such as ethanolamine) chelated copper compounds are considered less toxic to fish than copper sulfate and at least as effective in controlling parasites (Peppard etal. 1991). 

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