Solid reactivity/stability

STABREX is easier and simpler to use compared to any other oxidant available for industrial water treatment. The product is pumped directly from returnable transporters (PortaFeed Systems)17 with standard chemical feed equipment. Previously, the only practical ways to apply bromine were to oxidize bromide solutions on-site with chlorine in dual liquid feed systems, or with one of the solid organically-stabilized bromine products applied from sidestream erosion feeders. The former is cumbersome and complex, and the latter is prone to dusting and difficult to control. Other oxidants require complex handling and feed of toxic volatile gases, unstable liquids, multiple-component products, or reactive solids. Simplicity in use results in reduced risk to workers and to the environment. 

Strickley, R.G., and B.D. Anderson, Solid-state stability of human insulin. II. Effect of water on reactive intermediate partitioning in lyophiles from pH 2-5 solutions stabilization against covalent dimer formation. J Pharm Sci, 1997.86(6) 645-53. 

Dissolution rate, solid-state reactivity, stability... 

Dollimore [5] has discussed some aspects of the influence of the central atom on the thermal stabilities of solid coordination compounds. The most fully characterized compounds are those of Co, Cr and Pt. Central atoms of relatively small radius but high oxidation number coordinate most effectively. The possible influences of melting and dependences upon reaction conditions increase the difficulties of identification of the factors which control reactivity. Stabilities are influenced [5] by the electronic structure of the coordinated ion, whether this is a normal or a penetration compound. In the latter species, covalent bonding involves 3dHs4p orbitals, whereas in a normal coordination compound the 4s4pMd orbitals... 

Investigations on solidity and stability of XL-XLVl compounds at the stage of s-caprolactam polymerization were carried out to determine compatibility and stability of bis -(1 , 8 - benzoilene - 1,2 - benzimidazoles) and bis - (1 , 8 - naphthoilene - 1,2 -benzimidazoles) in reactive PCA mass. Obtained coloured polymer was investigated visually to homogeneity of solid solution, its solubility in H 2 SO 4, in the mixture of 80% formic and trifluoro - acetic acids in ratio 1 1 and in in - cresol. Ability of PCA melt to form into a fibre, and also molecular masses of dyed and undyed polymer with average viscosity were defined too. 

A survey of crystalline hydrates of /3-lactams was recently reported in order to probe the significance of crystallinity on the stability of reactive APIs [54], Compounds which contain the /3-lactam core, including penicillin derivatives, carbapenems and cephalosporins, are known to undergo hydrolysis both in solution and in the solid state [55, 56], Solid-state stability has been shown to be dependent on storage conditions and degree of crystallinity [57-59]. It has also been shown that even hydrates of /3-lactams, where the water is regarded as a potential reactant, can be stable in the solid state for years. 

Because the compounds studied by Quinkert, including 2-indanones 54 and 55, have a-phenyl-substituents at Cl and C3, one cannot conclude whether the benzocyclopentanone JC-system may contribute to the stability of the intermediate biradicals and facilitate the sohd-state reaction. In order to answer this question and to test the effect of methyl, oxygen, and sulfur as a-substituents, the solid reactivities of 2-indanone derivatives 80,81, and 82 (Scheme 22) were recently investigated and compared to those of 54 and 55 (Scheme 15) a reasonable answer was rapidly found. ... 

Chemical Reactivity - Reactivity with Water Reacts violently with water as a dry solid or when dissolved in ether. The hydrogen produced by the reaction with water is a major hazard and necessitates adequate ventilation Reactivity with Common Materials Can burn in heated or moist air Stability During Transport Normally stable imstable at high temperatures Neutralizing Agerus for Acids and Caustics Not pertinent Polymerization Not pertinent Inhibitor of Polymerization Not pertinent. 

Chemical Reactivity - Reactivity with Water Hot water may cause frothing. Reaction with cold water is slow and non-hazardous Reactivity with Common Materials No reaction Stability During Transport Stable Neutralizing AgerUs for Acids and Caustics Solid spills can usually be recovered before any significant reaction with water occurs. Flush area of spill with water Polymerization Very unlikely at ordinary temperatures, even in the molten state Inhibitor of Polymerization None. 

Chemical Reactivity - Reactivity with Water A slow, non-hazardous reaction occurs, forming propanolamine Reactivity with Common Materials No reactions Stability During Transport The product is stable if it is kept in contact with solid caustic soda (sodium hydroxide) Neutralizing Agents for Acids and Caustics Dilute with water and rinse with vinegar solution Polymerization This material will polymerize explosively when in contact with any acid Inhibitor of Potymerization Solid sodium hydroxide (caustic soda). 

Chemical Reactivity - Reactivity with Water Reacts vigorously with water with the release of flammable hydrogen gas Reactivity with Common Materials No reactions Stability During Transport Stable at temperatures below 225 C Neutralizing Agents for Acids and Caustics Neutralize only when accidental reaction with water is complete. Do not neutralize the flammable solid with aqueous solutions. Spent reaction solution may be neutralized with dilute solutions of acetic acid. Polymerization Not pertinent Inhibitor of Polymerization Not pertinent. 

Chemical Reactivity - Reactivity with Water Reacts slowly to form acetaldehyde. The reaction is generally not hazardous unless occurring in hot water or acids are present Reactivity with Common Materials Acids cause polymeri2ation Stability During Transport Stable but must be segregated from acids Neutralizing Agents for Acids and Caustics.- Not pertinent Polymerization Can polymerize in the presence of acids Inhibitor of Polymerization Dioctylamine Triethanolamine Solid Potassium Hydroxide. 

There are two basic ways of generating unstable species for matrix isolation studies. The first one consists in the formation of intermediates directly in a solid matrix. In the second, the reactive molecules are generated in the gas phase (at very low pressure) with subsequent stabilization by eondensation in an inert matrix at 10-20 K. 

BCG Cultures of live BCG cells in liquid or on solid media 1 Bacteria centrifuged from medium 2 Resuspension in stabilizer 3 Freeze-drying Viable count induction of sensitivity to tuberculin in guinea-pigs Exclusion of virulent mycobacteria absence of excessive dermal reactivity... 

Phase-transfer catalysis is a special type of catalysis. It is based on the addition of an ionic (sometimes non-ionic like PEG400) catalyst to a two-phase system consisting of a combination of aqueous and organic phases. The ionic species bind with the reactant in one phase, forcing transfer of this reactant to the second (reactive) phase in which the reactant is only sparingly soluble without the phase-transfer catalyst (PTC). Its concentration increases because of the transfer, which results in an increased reaction rate. Quaternary amines are effective PTCs. Specialists involved in process development should pay special attention to the problem of removal of phase-transfer catalysts from effluents and the recovery of the catalysts. Solid PTCs could diminish environmental problems. The problem of using solid supported PTCs seems not to have been successfully solved so far, due to relatively small activity and/or due to poor stability. 

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