For formaldehyde poisoning

The acrylate complex 10 was suggested to be the major solution species during catalysis, since the equilibrium in Scheme 5-11, Eq. (2) lies to the right (fQq > 100)-Phosphine exchange at Pt was observed by NMR, but no evidence for four-coordinate PtL, was obtained. These observations help to explain why the excess of phosphine present (both products and starting materials) does not poison the catalyst. Pringle proposed a mechanism similar to that for formaldehyde and acrylonitrile hydrophosphination, involving P-H oxidative addition, insertion of olefin into the M-H bond, and P-C reductive elimination (as in Schemes 5-3 and 5-5) [11,12]. 

Antidotes can change the chemical nature of a poison by rendering it less toxic or preventing its absorption. Formaldehyde poisoning can be treated with ammonia to promote formation of hexamethylenetetramine sodium formaldehyde sulfoxylate can convert mercuric ion to the less soluble metallic mercury and sodium bicarbonate converts ferrous iron to ferrous carbonate, which is poorly absorbed. Chemical inactivation techniques seldom are used today, however, because valuable time may be lost, whereas emetics, activated charcoal, and gastric lavage are rapid and effective. The treatment of choice for ingestion of either acids or alkalis is dilution with water or milk. Similarly, bums produced by acid or alkali on the skin should be treated with copious amounts of water. 

Schaarschmidt, A., H. Hoffmeier, and P. Nowak Applicability of absorption agents for removing poisons from tobacco smoke Chem. Zeit. 56 (1932) 911-913. Schaller, K.H., G. Triebig, and B. Beyer Determination of formaldehyde in tobacco smoke Investigations under experimental and field conditions Zbl. Hyg. Umweltmed. 189 (1989) 103-110. 

Solutions of formaldehyde, 30 to 50%, such as those used in preservatives, are listed as miscellaneous hazardous materials. These solutions are nonflammable, and the toxicity is below the requirements for a poison liquid. However, the material may still be carcinogenic. Formaldehyde solutions usually contain up to 15% methanol to retard polymerization. The four-digit UN identification number for nonflammable solutions is 2209. 

For formaldehyde oxidation, 20 wt% Mo/WC prepared by CVD with metal hexacarbonyl precursors showed a current density of 4 x 10 A/m at 0.3 V (vs RHE) and 323 K, whereas pure WC electrode showed 1.2 x 10 A/m (159). According to this report, the electrochemical activities could be enhanced because Mo might act as the center for removal of poisonous species and provide other pathways of aldehyde decomposition. 

Hydroxymethyl-6-methyluracil (1043) was prepared many years ago from 6-methyl-uracil and formaldehyde, or in other ways. Since 1956 it has received much attention in the USSR under the (transliterated) name pentoxyl or pentoxil. It is used in several anaemic and disease conditions. For example, a mixture of folic acid and pentoxyl quickly reduces the anaemia resulting from lead poisoning pentoxyl stimulates the supply of serum protein after massive blood loss it stimulates wound healing it stimulates the immune response in typhus infection and it potentiates the action of sulfonamides in pneumococcus infections (70MI21300). 

Methanol is a colourless liquid and boils at 337 K. It is highly poisonous in nature. Ingestion of even small quantities of methanol can cause blindness and large quantities causes even death. Methanol is used as a solvent in paints, varnishes and chiefly for making formaldehyde. 

Beyer and coworkers later extended these reactions to platinum clusters Ptn and have demonstrated that similar reaction sequences for the oxidation of carbon monoxide can occur with larger clusters [70]. In addition, they were able to demonstrate poisoning effects as a function of surface coverage and cluster size. A related sequence for Pt anions was proposed by Shi and Ervin who employed molecular oxygen rather than N2O as the oxidant [71]. Further, the group of Bohme has screened the mononuclear cations of almost the entire transition metal block for this particular kind of oxidation catalysis [72,73]. Another catalytic system has been proposed by Waters et al. in which a dimolybdate anion cluster brings about the oxidation of methanol to formaldehyde with nitromethane, however, a rather unusual terminal oxidant was employed [74]. 

If sampling is not followed immediately by analysis, the sample must be treated with a preservative, but not such as to falsify the analytical results use is made of 10% potassium dichromate solution, formaldehyde, hydrogen peroxide, alcoholic solution of phenol, mercuric chloride (about 5% solution), etc., a few drops being added. The last of these preserves milk very well for several days without altering its composition or disturbing the determinations, but its poisonous character necessitates precautions. 

Ingestion of methanol, particularly during the prohibition era, resulted in significant illness and mortality. Where epidemics of methanol poisoning have been reported, one-third of the exposed population recovered with no ill effects, one-third have severe visual loss or blindness, and one-third have died. Methanol itself is not responsible for the toxic effects but is rapidly metabolized in humans by alcohol dehydrogenase to formaldehyde, which is subsequently metabolized by aldehyde dehydrogenase to form... 

The reactor effluent contains about 25% formaldehyde, which is absorbed with the excess methanol and piped to the make tank. The latter feeds the methanol column for separation of recycle methanol overhead, the bottom stream containing the formaldehyde and a few percent methanol. The water intake adjusts the formaldehyde to 37% strength (marketed as formalin). The catalyst is easily poisoned so stainless-steel equipment must be used to protect the catalyst from metal contamination. 

According to Platonov et al. (309), nickel can be poisoned by H2S, S02, H2SO4, As203, and P206, after which it will direct the decomposition of formic acid preferentially in one of three possible ways above a critical amount of the poison the latter ceased to act selectively and the catalyst was deactivated. In another study (310) Platonov and co-workers demonstrated that over rhenium catalysts, partly poisoned with H2S or AS2O3, methanol was converted to formaldehyde in preference to the complete decomposition which occurred over the unpoisoned catalyst. However, rhenium sulfide itself was later shown to be a good catalyst for the reaction reported and consequently the poisoning phenomenon may not be applicable to this case (308). 

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