Hydrolysis hazard

Hydrolysis Hazardous waste chemical treatment mediod wherein chemical compounds are decomposed by a reaction with water agents such as alkaline solutions as well as high temperatures and pressures are often used to promote desired reaction. 

Derivation Frommonochloroacetic acid by reaction with potassium cyanide followed by hydrolysis. Hazard Strong irritant. 

Regulatory DOT nonregulated SARA 311/312/313 nonreportable Properties Wh. powd. < 5 p particle size char, odor insol. in water vapor pressure < 0.001 mm Hg m.p. 254 C b.p. > 400 C flash pt. (COC) > 265 C pH 8-10 > 99% act. 15.67% P, 27% N Toxicology May cause mild to mod. eye irritation, skin irritation, esp. on prolonged contact, Gl irritation, nausea, vomiting, diarrhea TSCAlisted Precaution Prod, sinks in water strong alkalis may cause hydrolysis Hazardous Decomp. Prods. PO NO, CO, combustion in presence of other materials may release PO NO, CO,... 

C decomp, moderate, with slow hydrolysis Hazards ICSC 0328 016-026-00-0 Irritant (Xi)... 

Friecairiion Fiamm. incompat. with strong oxidizing agents strong adds and aika-iis pronwle degradation by hydrolysis Hazardous Decomp. Prods. CO, COj, SO ... 

This hydrolysis reaction is accelerated by acids or heat and, in some instances, by catalysts. Because the flammable gas hydrogen is formed, a potential fire hazard may result unless adequate ventilation is provided. Ingestion of hydrides must be avoided because hydrolysis to form hydrogen could result in gas embolism. 

The importance of hydrolysis potential, ie, whether moisture or water is present, is illustrated by the following example. In the normal dermal toxicity test, namely dry product on dry animal skin, sodium borohydride was found to be nontoxic under the classification of the Federal Hazardous Substances Act. Furthermore, it was not a skin sensitizer. But on moist skin, severe irritation and bums resulted. 

The methacrylates ate slightly to essentially nontoxic to fish and other aquatic species. Hydrolysis data suggest rapid breakdown at alkaline conditions, and studies show that MMA is ultimately biodegradable ia sewage sludge samples. Based on this information, the methacrylates ate not considered to be a significant environmental hazard. 

Procedures for shipping boric acid esters depend on the particular compound. Aryl borates produce phenols when in contact with water and are therefore subject to shipping regulations governing such materials and must carry a Corrosive Chemical label. Lower alkyl borates are flammable, flash points of methyl, ethyl, and butyl borates are 0, 32, and 94°C, respectively, and must be stored in approved areas. Other compounds are not hazardous, and may be shipped or stored in any convenient manner. Because borate esters are susceptible to hydrolysis, the more sensitive compounds should be stored and transferred in an inert atmosphere, such as nitrogen. 

Chemical Reactivity - Reactivity with Water Very slow, not hazardous Reactivity with Common Materials Slow hydrolysis to acidic produas Stability During Transport Stable Neutralizing Agents for Acids and Caustics Not pertinent Polymerization Not pertinent Inhibitor of Polymerization Not... 

The chemistry of side reactions and by-products may also offer opportunities for increasing the inherent safety of a process. For example, a process involving a caustic hydrolysis step uses ethylene dichloride (EDC 1,2-dichloroethane) as a solvent. Under the reaction conditions a side reaction between sodium hydroxide and EDC produces small but hazardous quantities of vinyl chloride ... 

Since full analyses are carried out, a lot of data are generated. Every parameter is reviewed for trends that signal product aging or outright decomposition of the active principle this can be as cosmetic in nature as discoloration or as potentially hazardous as buildup of toxic derivatives. If the drug substance is an ester, for example, hydrolysis, particularly if moisture penetrates the primary packaging material, will decompose the compound into its acid and alcohol components. From a pharmaceutical or medical viewpoint, even if there is no toxicity issue involved, this will result in a loss of bioavailability. Even this is to be avoided because subpotency introduces therapeutic uncertainty and can go as far as lethal undertreatment. 

EPA. 1987f Measurement of hydrolysis rate constants for evaluation of hazardous waste land disposal. Volume 1. Data on 32 chemicals. Environmental Research Laboratory. Office of Research and Development. U.S. Environmental Protection Agency, Athens, GA. PB87-104349. 

Storage stability Store DF in lead and wax-lined carboys, high-density polyethylene bottles, or nickel-lined containers in well-ventilated areas. Never store DF with alcohols DF will react with alcohols to form lethal chemicals, such as crude GB. Incompatible with water, glass, concrete, most metals, natural rubber, leather, and organic materials like glycols. The acidic corrosive hydrolysis products may react with metals, such as Al, Pb, and Fe, to give off hydrogen gas, a potential fire and explosive hazard. 

Before the injected fluids migrate out of the injection zone or to a point of discharge or interface with USDW, the fluid will no longer be hazardous because of attenuation, transformation, or immobilization of hazardous constituents within the injection zone by hydrolysis, chemical interactions, or other means. 

Hydrolysis occurs when a compound reacts chemically with water (i.e., new chemical species are formed by the reaction), and can be a significant transformation process for certain hazardous wastes in the deep-well environment (see Table 20.7). Hydrolysis reactions fall into two major categories replacement and addition. The rates at which these reactions occur are also significant in a fate assessment because some take so long to occur that they will not take place during the analytical time frame (10,000 years). 

Listed Hazardous Organic Wastes for Which Hydrolysis May Be a Significant ... 

The major processes affecting the geochemical fate of hazardous inorganics are acid-base adsorption-desorption, precipitation-dissolution, complexation, hydrolysis, oxidation-reduction, and catalytic reactions. The significance of these processes to inorganic wastes is discussed only briefly here additional information on individual elements is given in Table 20.16. 

Most of the common 15 hazardous pesticides are chlorinated hydrocarbons. Adsorption can be an important process for most. All except DDT, endosulfan, and heptachlor resist hydrolysis, and most are also resistant to biodegradation. Kearney and Kaufman118 review conditions under which chlorinated pesticides are biodegraded. 

Hydrolysis is strongly pH-dependent, with L, dominant at low pH and kb dominant at high pH at pH 7, kn can often be most important. However, the detailed relationship of pH and rate depends on the specific values of kn, fca, and kb. If these rate constants are known, then the hydrolysis rate at any pH can be readily calculated. Mabey and Mill158 provide these data for a large number of organic compounds, and Ellington159-161 provides data on about 70 regulated hazardous pollutants. 

Ellington, J.J., Measurement of Hydrolysis Rate Constants for Evaluation of Hazardous Waste Land Disposal, Vol 1 Data on 32 Chemicals, EPA/600/3-86/043, NTIS PB87-140349, U.S. EPA, Washington,... 

Transformation Rates. A literature search was conducted to determine rates of oxidation, hydrolysis, photolysis, and biodegradation. When no values were found, we made estimates based on our experience, known rates for similar compounds, and structure-activity relationships. In cases where there was great uncertainty, a transformation rate of zero was assumed so that the compound would be considered persistent. This would force a more detailed fate assessment to be conducted if considerations of toxicity indicated that the compound might be hazardous. 

The principal reaction hazard attached to use of acetic anhydride is the possibility of rapid and exothermic acid-catalysed hydrolysis unless the conditions prevailing (temperature, agitation, order of mixing, proportion of water) are such as to promote smooth and progressive hydrolysis with adequate heat removal. The examples below illustrate these factors. 

Cochrane, A. R. G. etal., School Sci. Rev., 1977, 58, 706-708 Hazards of using perchloric acid to hydrolyse DNA are stressed. Perchloric acid can cause ignition of any organic material, even a considerable time after contact. Other acids to effect hydrolysis are suggested. 

Although uncontrolled reaction of xenon hexafluoride and moisture produces explosive xenon trioxide, controlled action by progressive addition of limited amounts of water vapour with agitation to a frozen solution of the hexafluoride in anhydrous hydrogen fluoride at —196° C to give xenon oxide tetrafluoride or xenon dioxide difluoride is safe [1], Controlled hydrolysis in solution in hydrogen fluoride is, however, described as hazardous [2],... 

Ellington, J. J., Stancil, Jr., F. E., Payne, W. D. (1987a) Measurements of Hydrolysis Rate Constant for Evaluation of Hazardous Land Disposal Volume I. Data on 32 Chemicals U.S. EPA, EPA/600/3-86/043, Athens, GA. 

Viscous liquid with a strong fishy odor. This material is hazardous through inhalation and ingestion, and produces local skin/eye impacts. Hydrolysis product TR is formed when there is only a limited amount of water present. It is highly reactive and toxic. 

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