Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants Volume 4 (2000) / Chapter Skim
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B12 4-Methyl-2-Pentanone
B12 4-Methyl-2-Pentanone
Pages 240-263
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Formula: CAS no.: Synonym: Molecular weight: Boiling point: Melting point: Vapor pressure: Conversion factors at 25 °C, 1 atm: CH3COCH2CH2(CH3~2 108-10-1 Methyl isobutyl ketone; hexone 100.2 115.~°C -84.7°C 15 torr at 25°C lppm=4.09mg/m3 1 mg/m3 = 0.24 ppm OCCURRENCE AND USE As a solvent, MIBK is used in paints, varnishes, lacquers, aircraft dopes, rubber cements, and adhesives (ACGIH ~ 991~. It is not used per se in spacecraft, but 240
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(1992) conducted a neurobehavioral study in which MIBK concentrations in the blood and the breath were measured in human volunteers exposed to MIBK at 88 ppm for 4 h.
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(1990~. In rats exposed to MIBK at 512 ppm for 2 h, MIBK reached a concentration of 25.3 ,ug/mL in blood with 51.2% distributed to red blood cells (RBCs)
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Acute and Short-Term Exposures In vivo studies demonstrated that MIBK exposures can lead to mucosal irritation, central-nervous-system (CNS) depression, renal damage, changes in hepatic weight, and death.
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After the exposure, there were no changes in hematology (the red- and white-blood-cell counts, hematocrit, hemoglobin concentration) and clinical chemistry (the plasma concentrations of sodium, potassium, calcium, total phosphorus, chloride, cholesterol, total bilirubin, albumin, total protein, uric acid, creatinine, glucose, and alkaline phosphatase, as well as blood urea nitrogen)
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They observed lacrimation in rats and mice exposed to 2000 ppm. MIBK's acute exposures at lower concentrations are not known to produce overt irritation in laboratory animals.
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(1992) , who reported that during a 4-h exposure of ~ 0 men and 7 women to MTBK at 88 ppm, there were no significant changes in the choice reaction time, simple reaction time, ability to simultaneously perform an auditory tone discrimination task together with a compensatory visual tracking task, memory scanning, postural steadiness, and mood states after 45 min or 2.75 h of exposure.
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(1983, 1984) found that industrial solvent vapors reduced the duration of immobility in the first 3 min.
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(1987) detected an increased incidence of hyaline droplets and epithelial regeneration in proximal tubular cells in only the male rats exposed to MIBK at 2000 ppm.
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and clinical chemistry (the plasma concentrations of sodium, potassium, calcium, total phosphorus, chloride, cholesterol, total bilirubin, albumin, total protein, uric acid, creatinine, glucose, and alkaline phosphatase; the serum acid phosphatase and serum glucuronidase activities; as well as blood urea nitrogen) in dogs end monkeys.
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The total protein urinary excretion was increased only in male rats exposed to MIBK at 1000 ppm. However, there were no exposure-related changes in the serum concentrations of creatinine and urea nitrogen.
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dehydrogenase, and alkaline phosphatase. The liver-weight-tobody-weight ratio was increased in male rats and male mice exposed to MIBK at ~ 000 ppm.
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At the highest exposure concentration used, 3000 ppm, maternal toxicity was detected in both rats and mice based on cTinical signs. Pregnant rats exposed to MIBK at 3000 ppm had decreased food consumption, decreased body-weight gain, and increased liver-weight-to-body-weight ratio.
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(1991) showed that "MIBK selectively induced cytochrome P-450 isozymes leading to the metabolic activation" of n-hexane.
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(1987) in rats exposed to MTBK at 250 or 1000 ppm,6 h/d,5 d/w for 14 w, is not included in AC derivation because the 23-35% increases in serum cholesterol are not considered TABLE 12-4 Exposure Limits Set by Other Organizations Organization Exposure Limit, ppm Reference ACGIH's TLV 50 (TWA)
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and Phillips et al. showed that continuous or repetitive MIBK exposures could increase the incidence of hyalin droplet degeneration in proximal tubules in the kidney of male rats (MacEwen et al.1971; Phillips et al.1987~.
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found that MIBK exposures at >1000 ppm could result in the Toss of reflexes or lethargy in rats or mice.
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1992. Neurobehavioral effects from acute exposures to methyl isobutyl ketone and methyl ethyl ketone.
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1979a. Effects of acetone, methyl ethyl ketone, and methyl isobutyl ketone on a match-to-sample task in the baboon.
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1988. Mutagenicity studies on ketone solvents: Methyl ethyl ketone, methyl isobutyl ketone, and isophorone.
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1938. Acute response of guinea pigs to inhalation of methyl isobutyl ketone.
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