Heavy metals salts

Dissolves in alkaline solutions to give purple-red solutions which are precipitated as lakes by heavy metal salts. Occurs naturally as a glucoside in madder but produced synthetically by fusing anthraquinone-2-sulphonic acid with NaOH and some KCIO3. Applied to the mordanted fibre. Al(OH)3 gives a bright red lake, Cr(OH)3 a red lake, FefOH) ... 

M.p. —80°C, b.p. 37°C. Prepared from sodium azide and acid or (N2Hj) plus nitrous acid, HNO2. Heavy-metal salts, azides, are used as detonators, alkali metal salts are stable and azides are used synthetically in organic chemistry. 

Complexes of DMAC and many inorganic haHdes have been reported (20). These complexes are of iaterest because they catalyze a number of organic reactions. Complexes of DMAC and such heavy metal salts as NiBr2 exert a greater catalytic activity than the simple salts (21). The crystalline complex of SO and dimethylacetamide has been suggested for moderating the reaction conditions ia sulfation of leuco vat dyestuffs (22). 

Health and Safety Factors. Although butynediol is stable, violent reactions can take place in the presence of certain contaminants, particularly at elevated temperatures. In the presence of certain heavy metal salts, such as mercuric chloride, dry butynediol can decompose violently. Heating with strongly alkaline materials should be avoided. 

Before the fibers can be spun into yams, a certain amount of preparation is necessary for cleaning and removal of undesirable accessory materials such as fat, wax, gum, or pulp. The weighting of sUk is a process to counter the weight loss resulting from degumming the fibers using heavy metal salts of tin or bismuth. This process affects the durabUity and long term preservation. 

Some phosphides, such as titanium phosphide [12037-65-9] TiP, can be prepared bypassing phosphine over the metal or its haUde. Reaction of phosphine with heavy metal salt solutions often yields phosphines that may contain unsubstituted hydrogens. Phosphides may also be prepared by reducing phosphoms-containing salts with hydrogen, carbon, etc, at high temperatures, the main example of which is the by-product formation of ferrophosphoms in the electric furnace process for elemental phosphoms. Phosphoms-rich phosphides such as vanadium diphosphide [12037-77-3] may be converted to lower phosphides, eg, vanadium phosphide [12066-53-4] by thermal treatment. 

Bina Selenides. Most biaary selenides are formed by beating selenium ia the presence of the element, reduction of selenites or selenates with carbon or hydrogen, and double decomposition of heavy-metal salts ia aqueous solution or suspension with a soluble selenide salt, eg, Na2Se or (NH 2S [66455-76-3]. Atmospheric oxygen oxidizes the selenides more rapidly than the corresponding sulfides and more slowly than the teUurides. Selenides of the alkah, alkaline-earth metals, and lanthanum elements are water soluble and readily hydrolyzed. Heavy-metal selenides are iasoluble ia water. Polyselenides form when selenium reacts with alkah metals dissolved ia hquid ammonia. Metal (M) hydrogen selenides of the M HSe type are known. Some heavy-metal selenides show important and useful electric, photoelectric, photo-optical, and semiconductor properties. Ferroselenium and nickel selenide are made by sintering a mixture of selenium and metal powder. 

Other modifications have special but more limited apphcations. A centrifugal bowl may contain, instead of disks, several aimular baffles that take the hquid through a labyrinth path before discharge. The multiple cylinders increase cake capacity to as much as 70 L for easily sedimented sohds. This centrifuge is used for clarification of food symps and antibiotics (qv), and for recovery of heavy metallic salts and catalysts (see Fig. 14c). 

Hydrogen sulfide causes the precipitation of sulfides from many heavy-metal salts. The classical quaUtative analysis scheme depends on precipitation of the sulfides of Hg, Pb, Bi, Cu, Cd, As, Sb, and Sn under acid conditions and the sulfides of Co, Ni, Mn, Zn, and Fe under ammoniacal conditions. 

Carboxylate, sulfonate, sulfate, and phosphate ate the polar, solubilizing groups found in most anionic surfactants. In dilute solutions of soft water, these groups ate combined with a 12—15 carbon chain hydrophobe for best surfactant properties. In neutral or acidic media, or in the presence of heavy-metal salts, eg, Ca, the carboxylate group loses most of its solubilizing power. 

The heavy metal salts, ia contrast to the alkah metal salts, have lower melting points and are more soluble ia organic solvents, eg, methylene chloride, chloroform, tetrahydrofiiran, and benzene. They are slightly soluble ia water, alcohol, ahphatic hydrocarbons, and ethyl ether (18). Their thermal decompositions have been extensively studied by dta and tga (thermal gravimetric analysis) methods. They decompose to the metal sulfides and gaseous products, which are primarily carbonyl sulfide and carbon disulfide ia varying ratios. In some cases, the dialkyl xanthate forms. Solvent extraction studies of a large number of elements as their xanthate salts have been reported (19). 

U-in alkaline-reducing vats, a soluble leuco compound forms I-insoluble J-tends to thicken or gel the solution p-dye precipitated as heavy-metal salt or color acid a-may bleed or stain, very sparingly soluble S-dissolves (solubiUty 1%). 

In the presence of the organic siHcate, the heavy-metal salts trigger the chain extension and cross-linking reactions that lead to siHcone mbber and volatile ethanol as a byproduct. Useful metal soaps iaclude stannous octanoate [1912-83-0], ziac octanoate [557-09-5], dibutyltin dilaurate [77-58-7], and dibutyltin diacetate [1067-33-0]. The reactivity of the different salts varies considerably. Stannous octanoate effects a cure ia 0.5—2 min ziac octanoate may require 24—96 h the dibutyltin dilaurate, 10—20 min. Heat and moisture accelerate the curing rate, but to a lesser degree than ia the case of the polysulfide mbbers. 

Methyl picric acid (heavy metal salts of)... 

Salt formation. The resin acids have a low acid strength. The pa s (ionization constants) values of resin acids are difficult to obtain, and values of 6.4 and 5.7 have been reported [23] for abietic and dehydroabietic acids, respectively. Resin acids form salts with sodium and aluminium. These salts can be used in detergents because of micelle formation at low concentrations. Other metal salts (resinates) of magnesium, barium, calcium, lead, zinc and cobalt are used in inks and adhesive formulations. These resinates are prepared by precipitation (addition of the heavy metal salt to a solution of sodium resinate) or fusion (rosin is fused with the heavy metal compound). 

The process has seen decreasing use due to increasing disposal problems with the spent catalyst, which is classified as a heavy metal salt. 

When Sommer tried to prepare the potassium salt of 3 the crystal-fine product obtained exploded with violence as he spread it upon a porous plate. The potassium salt was, however, isolated and analyzed by Browne and Hoel. It is anhydrous but very soluble in water. Several other salts have been prepared. The slightly soluble heavy-metal salts are very sensitive to shock and may explode violently even under water. 

Dihydro-2f/-pyran-2-one has been prepared by reductive cycliza-tion of 5-hydroxy-2-pentynoic acid [2-Pentynoic acid, 5-hydroxy-], which is obtained in two steps from acetylene [Ethyne] and ethylene oxide [Oxirane] 3 and by the reaction of dihydropyran [277-Pyran, 3,4-dihydro-] with singlet oxygen [Oxygen, singlet].4,5 2ff-Pyran-2-one has been prepared by pyrolysis of heavy metal salts of coumalic acid [2//-Pyran-5-carboxylic acid, 2-oxo-],8 by pyrolysis of a-pyrone-6-carboxylic acid [211 - Pyran-6-carboxyl ic acid, 2-oxo-] over copper,7 and by pyrolysis of coumalic acid over copper (66-70% yield).8... 

Potassium Methylnitraminate. K.CH302N2 fine needles, which expl violently on heating. 1 According to Davis (Ref 2), the heavy metal salts of methylnitramine are primary explosives, but have not been investigated extensively Refs 1) Beil 4, 567, (568) [968]... 

It fonns expl heavy metal salts, which according to Urbanski, are weaker initiators than the corresponding metal salts of methylenedi-isonitramine. The decreasing order of brisance of these salts, when primed with MF, in the Pb plate test were Na, Ca, Ba, H and Pb Refs 1) T. Urbanski T, Wesolowski, Wiad-TechnUzbr 18, 28 (1932) 2) T. Urbanski,... 

The taste of saccharin was further studied, and it was found that (1) the alkaline-earth-metal salts are sweet, whereas the heavy-metal salts are astringent (2) the sweet taste is lost if the sulfimide ring is cleaved, or if... 

An aqueous solution of 33% of propargyl alcohol gives rise to an unexpected detonation in a sulphuric medium (acid at 56%). Indeed, this reaction is thought to be safe. It was thought that this accident was either linked to difficulties in cooling or the presence of a heavy metal salt (see next reaction). 

Slimicide and biocide toxic pollutants containing pentachlorophenol are used at mills in the pulp, paper, and paperboard industry. Initially, pentachlorophenol was used as a replacement for heavy metal salts, particularly mercuric types. Trichlorophenols are also used because of their availability as a byproduct from the manufacture of certain herbicides. Formulations containing organo-bromides and organo-sulfur compounds are also being used. Substitution of alternative slimicide and biocide formulations can lead to the virtual elimination of pentachlorophenol and trichlorophenol from these sources. 

An example of some of the newer regulations is the restriction against the use of the popular mud dispersant, chrome lignosulfonate. It is expected that this regulation is merely the initial step toward ruling out the use of all heavy metal salts commonly employed in the formulation of well fluids because of their toxicity to aquatic life and humans. This means that the use of zinc and lead, in addition to chromium, may not be allowed in the future. At least one major oil company has already taken steps in this direction by ruling out the use of heavy metal salts in any well fluid in their worldwide operations. 

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