Acetone exposure

Intermediate 10 must now be molded into a form suitable for coupling with the anion derived from dithiane 9. To this end, a che-moselective reduction of the benzyl ester grouping in 10 with excess sodium borohydride in methanol takes place smoothly and provides primary alcohol 14. Treatment of 14 with methanesulfonyl chloride and triethylamine affords a primary mesylate which is subsequently converted into iodide 15 with sodium iodide in acetone. Exposure of 15 to tert-butyldimethylsilyl chloride and triethylamine accomplishes protection of the /Mactam nitrogen and leads to the formation of 8. Starting from L-aspartic acid (12), the overall yield of 8 is approximately 50%, and it is noteworthy that this reaction sequence can be performed on a molar scale. 

Animal studies have shown MEK to enhance the development of or increase the severity of neurotoxic effects due to methyl n-butyl ketone, ethyl butyl ketone, -hexane, and 2,5-hexanedione."MEK exposure did not, however, potentiate the neurobehavioral test decrements produced by acetone. Exposure to 200 ppm MEK or 100 ppm MEK plus 12 5 ppm acetone for 4 hours did not produce any significant effects in a variety of behavioral performance tests, whereas exposure to 250 ppm acetone caused some mild decrements. The liver and kidney toxicity of haloalkane solvents may also be potentiated by MEK. ... 

Factors that inhibit or alter the activity of the mixed function oxidase enzymes may increase the risk from exposure to the indicator compounds in the aromatic EC5-EC9 fraction (the BTEXs), the aromatic EC>16-EC35 fraction (the carcinogenic PAHs in this fraction) and a constituent of the aliphatic I < C5IiCH fraction (//-hexane). For example, concurrent alcohol consumption may increase the risk of central nervous system depression from the BTEXs, ototoxicity from toluene, and hematotoxicity from benzene. Acetone exposure may increase the risk of peripheral neuropathy of n-hexane. People who take haloperidol, acetaminophen, or aspirin, or who have a nutritionally inadequate diet, may also be more susceptible to the toxicity of these agents. ATSDR (1995f) noted that a substantial percentage of children consume less than the recommended dietary allowances of certain nutrients. 

CR dissolved in acetone was applied to the skin of C3H and Porton-strain mice at 1 mg (equivalent to 40 mg kg-1) daily for 12 weeks (Marrs et al, 1982). 80 weeks after the end of dosing, animals were sacrificed. A high incidence of fatty infiltration of the liver might have been due to acetone exposure, but otherwise there was no abnormal histopathology. 

Lower a cover slip gently onto the filter at a slight angle to reduce the possibility of forming air bubbles. If more than 30 seconds have elapsed between acetone exposure and triacetin application, glue the edges of the cover slip to the slide with lacquer or nail polish. 

In Fig. 3, typical cyclic voltammograms of the C[4]RA membrane in background electrolyte, without the marker present 3a, with hydroquinone present and under the addition of two different analytes are presented 3b + 3c. The oxidation peak of hydroquinone appeared at 0.2 V vs. Ag/AgCl electrode in all cases. The reduction of hydroquinone was observed at -0.27 V vs. Ag/AgCl electrode for the acetone exposure and -0.33 V vs. Ag/AgCl electrode for the chloroform exposure. Analysis of the peak heights, with respect to the baseline (see Fig. 3) for oxidation and reduction result in a averaged relative increase of the current and therefore the permeability of 265 % for a concentration of 13 mM of acetone and 1500 % for a concentration of 6.25 mM of chloroform. 

Acetone was once considered a relatively harmless chemical. However, as more has become known about acetone in recent years, regulations on its use have been tightened. Special trainir and equipment are now required for personnel v dio use acetone. Both the Occupational Safety and Health Administration (OSHA) and the National Institute for Occupational Safety and Health (NIOSH) have established wodq>lace limits for acetone exposure. 

Physical Properties. Furfuryl alcohol (2-furanmethanol) [98-00-0] is aHquid, colorless, primary alcohol with a mild odor. On exposure to air, it gradually darkens in color. Furfuryl alcohol is completely miscible with water, alcohol, ether, acetone, and ethyl acetate, and most other organic solvents with the exception of paraffinic hydrocarbons. It is an exceUent, highly polar solvent, and dissolves many resins. 

Material Safety Data Sheets (MSDS) issued by suppHers of acetone ate requited to be revised within 90 days to include new permissible exposure limits (PEL). Current OSHA PEL (54) and ACGIH threshold limit values (TLV) (55) ate the same, 750 ppm TWA and 1000 ppm STEL. Eot comparison, the ACGIH TWA values for the common mbbing alcohols are ethyl, 1000, and isopropyl, 400 ppm. A report on human experience (56) concluded that exposure to 1000 ppm for an 8-h day produced no effects other than slight, transient irritation of the eyes, nose, and throat. 

Pure, freshly distilled aniline is a colorless, oily Hquid that darkens on exposure to light and air. It has a characteristic sweet, aminelike aromatic odor. Aniline is miscible with acetone, ethanol, diethyl ether, and benzene, and is soluble in most organic solvents. Its soIubiHty characteristics in water are as follows ... 

Amino-2-hydroxybenZOiC acid. This derivative (18) more commonly known as 4-aminosa1icy1ic acid, forms white crystals from ethanol, melts with effervescence and darkens on exposure to light and air. A reddish-brown crystalline powder is obtained on recrystallization from ethanol —diethyl ether. The compound is soluble ia dilute solutioas of nitric acid and sodium hydroxide, ethanol, and acetone slightly soluble in water and diethyl ether and virtually insoluble in benzene, chloroform or carbon tetrachloride. It is unstable in aqueous solution and decarboxylates to form 3-amiaophenol. Because of the instabihty of the free acid, it is usually prepared as the hydrochloride salt, mp 224 °C (dec), dissociation constant p 3.25. 

Vanadium (metal) [7440-62-2] M 50.9, m 1910°, d 6.0. Cleaned by rapid exposure consecutively to HNO3, HCl, HF, de-ionised water and reagent grade acetone, then dried in a vacuum desiccator. 

Solvents acetone, methyl ethyl ketone (MEK), toluene, xylene, glycol, ethers, alcohol defats and dries skin some may be absorbed may carry other components through skin high volatility, exposure possible irritation central nervous system depression (e.g. dizziness, loss of coordination) low to high toxicity, longterm effects... 

The ketimine is an acetone-blocked diamine. The synthesis and applications of ketimines will be discussed later. The curing concept for the adhesive is shown in Fig. 7. Phenol-blocked prepolymers would normally unblock at approximately 150°C. However, an aliphatic diamine, generated by the hydrolysis of the ketimine to an aliphatic diamine and ketone as a result of exposure to the moisture in the air, is sufficient to cure the windshield adhesive at room temperature. 

The methacrylic backbone structure makes the spherical Toyopearl particles rigid, which in turn allows linear pressure flow curves up to nearly 120 psi (<10 bar), as seen in Fig. 4.45. Toyopearl HW resins are highly resistant to chemical and microbial attack and are stable over a wide pH range (pH 2-12 for operation, and from pH 1 to 13 for routine cleaning and sanitization). Toyopearl HW resins are compatible with solvents such as methanol, ethanol, acetone, isopropanol, -propanol, and chloroform. Toyopearl HW media have been used with harsh denaturants such as guanidine chloride, sodium dodecyl sulfate, and urea with no loss of efficiency or resolution (40). Studies in which Toyopearl HW media were exposed to 50% trifluoroacetic acid at 40°C for 4 weeks revealed no change in the retention of various proteins. Similarly, the repeated exposure of Toyopearl HW-55S to 0.1 N NaOH did not change retention times or efficiencies for marker compounds (41). 

A number of diarylmethyl alkylpiperazines, such as, for example lidoflazine, have found use as coronary vasodilators for the treatment of angina. The most recent of these interestingly incorporates a 2,6-dichloroaniline moiety reminiscent of antiarrhythmic agents. Treatment of the piperazine carboxamide 124 with acetone leads to formation of the nitrogen analogue of an acetal, the aminal 125. Alkylation of the remaining secondary nitrogen with chloroamide 126 leads to the intermediate 127. Exposure to aqueous acid leads to hydrolysis of the aminal function... 

Many engineering thermoplastics (e.g., polysulfone, polycarbonate, etc.) have limited utility in applications that require exposure to chemical environments. Environmental stress cracking [13] occurs when a stressed polymer is exposed to solvents. Poly(aryl ether phenylquin-oxalines) [27] and poly(aryl ether benzoxazoles) [60] show poor resistance to environmental stress cracking in the presence of acetone, chloroform, etc. This is expected because these structures are amorphous, and there is no crystallinity or liquid crystalline type structure to give solvent resistance. Thus, these materials may have limited utility in processes or applications that require multiple solvent coatings or exposures, whereas acetylene terminated polyaryl ethers [13] exhibit excellent processability, high adhesive properties, and good resistance to hydraulic fluid. 

Schultz and Ganguly, in 1925, noted that the surface of pulverized TNT became colored on exposure to sunlight. They concluded that tautomeric quinoximes were formed thru an unstable intermediate. In acetone, a stable intermediate formed (Ref 1). Gray, Bonomo and Denner (Ref 8) could not repeat their results Leighton and Lucy studied o-nitrobenzalde-... 

---