Tertiary Butyl Acetate Research Articles

Determination of certain VOCs in paints and architectural coatings by dynamic headspace gas chromatography-mass spectrometry.

A quantitative method for the determination of the following VOCs: acetone, dichloromethane, dimethyl carbonate, methyl acetate, tertiary butyl acetate, chlorobenzotrifluoride (4-CBTF) and propylene carbonate in paints was developed in support of Environment and Climate Change Canada's Automotive Refinishing Product and Architectural Coatings VOC Concentration Limits regulations. These compounds are excluded from the VOC definition by Canadian Environmental Protection Act (CEPA) regulations, and their content do not contribute to the overall VOC content in products for regulatory purposes. The method is based on Dynamic Headspace GC-MS. It was determined that activated carbon is the best trapping medium for these compounds. The technique has been compared to a currently used direct injection technique, with comparable results. Contrary to the direct injection method which requires complex sample handling prior to injection in the gas chromatograph, the dynamic headspace method practically eliminates the need for sample handling allowing for much shorter sample turnover and reducing the possibility of sampling handling errors.

Molecular Characterization of a Novel Family VIII Esterase with β-Lactamase Activity (PsEstA) from Paenibacillus sp.

Molecular information about family VIII esterases, which have similarities with class C β-lactamases and penicillin-binding proteins, remains largely unknown. In this study, a novel family VIII esterase with β-lactamase activity (PsEstA) from Paenibacillus sp. was characterized using several biochemical and biophysical methods. PsEstA was effective on a broad range of substrates including tertiary butyl acetate, glyceryl tributyrate, glucose pentaacetate, olive oil, and p-nitrophenyl esters. Additionally, PsEstA hydrolyzed nitrocefin, cefotaxime, and 7-aminocephalosporanic acid. Interestingly, two forms of immobilized PsEstA (CLEAs-PsEstA and mCLEAs-PsEstA) showed high recycling property and enhanced stability, but hybrid nanoflowers (hNFs) of PsEstA require improvement. This study provides a molecular understanding of substrate specificities, catalytic regulation, and immobilization of PsEstA, which can be efficiently used in biotechnological applications.

Subchronic, reproductive, and maternal toxicity studies with tertiary butyl acetate (TBAC)

Tertiary-butyl acetate (TBAC) was tested for subchronic toxicity in rats and mice and reproductive toxicity in rats at inhalation concentrations of 0, 100, 400 or 1600ppm. An oral maternal toxicity study was conducted in rats at dose levels of 0, 400, 800, 1000 and 1600mgkg−1d−1. In the inhalation studies, hematology, clinical chemistry, urinalysis, gross pathology and the majority of body weight and feed consumption values were unaffected. Exposure to TBAC at concentrations of 400ppm and higher caused transient hyperactivity in mice and some evidence of increased motor activity counts in male rats at the 1600ppm exposure level. TBAC caused α2u-globulin accumulation in male rat kidneys from all exposure groups and increased liver weights in 1600ppm rats and mice. Levels of thyroxin were decreased in male mice exposed to 1600ppm TBAC for 4weeks but otherwise thyroid endpoints were unaffected in rats and mice at either the 4 or 13weeks time points. There was no evidence or immunotoxicity or reproductive toxicity in rats. Pregnant rats receiving 1000mgkg−1d−1 TBAC exhibited severe signs of acute neurotoxicity and decreased feed consumption and body weight gain. Fetal viability and growth were unaffected.

Comprehensive environmental impact assessment of exempt volatile organic compounds in California

Abstract Regulatory agencies control emissions of volatile organic compounds (VOCs) because they react with nitrogen oxides in the presence of sunlight to yield tropospheric or ground-level ozone. However, reaction rates vary widely depending upon the type of VOC. Most VOC regulations developed in the United States consist of mass-based limits, except that VOCs found to be minimally reactive are exempted from regulations. However, the granting of VOC exemptions may lead to greater emissions of the VOCs so exempted. In this paper, we establish and describe a comprehensive approach that assesses several impacts of these greater emissions for VOCs proposed for exemption due to their negligible contribution to tropospheric ozone formation. These impacts include changes to tropospheric ozone, secondary organic aerosol, stratospheric ozone depletion, climate, other media (water and soil), indoor exposure, health, and the economy. This approach was applied to several VOCs: tertiary-butyl acetate (t-BAc), methyl formate, and nine fluorinated organic compounds, and the results are presented here. It is concluded that this comprehensive approach should be considered by regulatory agencies when exempting a VOC.

Comparative study on separation and characterization of high melting point macro- and micro-crystalline waxes

In order to separate and characterize the high melting point macro- and micro-crystalline waxes from two different waste crudes (El-Ameria heavy slack wax and Alexandria crude petrolatum, respectively), one stage fractional crystallization has been done to separate these waxes by using different solvents at different fractionating solvent ratios ranging from 4:1 to 10:1 by weight and at constant washing solvent ratio of 2:1. The solvents used are butyl acetate, tertiary butyl acetate and cyclohexane at ambient temperature of 20 °C. Also, the fractionating temperature was studied in the range of 20–40 °C. The resulting products were subjected to bauxite adsorption treatment technique to bleach and purify the waxes. Also, different tools of analysis such as GC, XRD, DSC & TGA, H NMR, and SEM were used to characterize and compare the produced waxes. Data revealed that, butyl acetate solvent at solvent ratios of 6:1 and 8:1 by weight at fractionating temperature of 40 °C were selected as the most suitable conditions for obtaining the highest melting point macro- and micro-crystalline waxes having different n-paraffin contents, crystallinities, thermal characteristics, and degrees of branching and owning different crystal sizes. These waxes are considered as ceresins and can be used in different industrial applications.

Tertiary-butyl acetate metabolism, toxicity, and human health considerations

Tertiary-butyl acetate (TBAC) (CAS No. 540-88-5) is an organic solvent with a potential for occupational and environmental exposure as a result of its use in industrial coatings, adhesives, inks, and degreasers. The objective of these studies was to extend the toxicological database upon which health hazard and risk assessments of TBAC can be made. The metabolism of TBAC was studied in rats exposed by inhalation for 6 h to concentrations of 100 or 1000 ppm. There was an evidence of partial saturation of TBAC absorption and metabolism at some concentration below 1000 ppm. Approximately 5% of the low dose and 26% of the high dose was expired without change within 12 h, while the retained material was rapidly metabolised and excreted, mostly in the urine, within 24 h. Very little radioactivity remained in the tissues after day 7. The metabolism of TBAC appears to follow two major routes: hydroxylation of the tertiary-butyl moiety to form 2-hydroxymethylisopropyl acetate and ester hydrolysis to form tertiary-butyl alcohol (TBA). A minor route involves oxidation of the acetate moiety. Based on the proportion of metabolites that can clearly be assigned to one or the other major pathway, hydroxylation of the tertiary-butyl moiety prevails at 100 ppm, while hydrolysis of the ester bond predominates at 1000 ppm. Based on nose-only inhalation exposure of rats to TBAC for 6 h, the LC50 for males and females combined is approximately 4200 ppm. Clinical signs included exaggerated breathing, staggering, tremors, and lethargy approximately 1 h after the exposure, but all surviving rats appeared normal from 24 h until the end of the 14 day observation period. An LC50 was not identified for mice. After exposure of whole body for 6 h to 3000 ppm, the highest concentration tested, all mice were prostrate for most of the exposure time, but there were no deaths. Groups of five male and five female Sprague-Dawley rats were exposed nose-only to 0, 100, 400, or 1600 ppm TBAC 6 h day−1 5 days wk−1 for 2 weeks. There were no effects on body weight, feed or water consumption, or necropsy findings. Male rats exposed to 1600 ppm had increased liver weights and hypertrophy of centrilobular hepatocytes. An increased proportion of cortical tubule cells with hyaline droplet accumulation was observed in all treated groups of males. Groups of five male and five female CD-1 mice were exposed whole body to 0, 190, 375, 750, or 1500 ppm TBAC 6 h day−1 for 14 consecutive days. There were no effects on body weight, feed consumption, or necropsy findings. Liver weights were increased in female mice at 750 and 1500 ppm. Minimal hypertrophy of centrilobular hepatocytes was found in female mice at 375, 750, and 1500 ppm and in male mice at 1500 ppm TBAC. TBAC did not induce gene mutations in bacterial tests with strains of S. typhimurium and E. coli. Further, there was no evidence of clastogenic activity from tests either for the induction of chromosomal aberrations in human lymphocytes in vitro in the presence or absence of S9 mix or for the induction of micronuclei in bone marrow cells of rats exposed by inhalation for 6 h to 1600 ppm TBAC. These results are relevant to human health risk assessment and are discussed in the context of previous studies. The weight of the scientific evidence supports the conclusion that TBAC has lower acute toxicity than previously suggested, that it is rapidly excreted when inhaled, and that neither TBAC nor its TBA metabolite are genotoxic or potential human carcinogens.

Photochemical reactivities of common solvents: comparison between urban and regional domains

Solvents are one of the most abundant sources of anthropogenic VOCs in the atmosphere, and can comprise a large number of organic compounds having different impacts on the rate and amount of ozone formation. A three-dimensional photochemical air quality model has been used to study the relative impacts of eight solvents, acetone, ethane, ethanol, isobutane, m-xylene, tertiary butyl acetate (TBA), para-chlorobenzotrifluoride (PCBTF) and benzotrifluoride (BTF) in three very different domains: Los Angeles, an urban area with high ozone and NO x levels; the Swiss Plateau, a more regional domain with much lower ozone and NO x levels: and Mexico City, a very high VOC urban area with high ozone levels. The results show that there can be a wide range of VOC reactivities under variable environmental conditions. Variability also exists between metrics, which are used to quantify reactivity. In most cases, halogenated aromatics were the least reactive and isobutane and m-xylene the most. The results here, finding that normalized reactivities are less variable than the absolute reactivity, support the applicability of relative VOC reactivity scales for use in air quality management.

Active Components in Clay Condensates and Extracts as Potential Geocatalysts

AbstractConversion of tertiary butylacetate to isobutylene and acetic acid and cracking of n-octane were used as model reactions to monitor the catalytic activity of a condensate and aqueous extract derived from a sample of montmorillonite. The condensate was obtained by condensing the vapor phase evolved on heating the clay and the extract was derived from the clay by prolonged water extraction. Both condensate and extract were colloidal systems, which were separated into solid and liquid fractions by distillation. Reactions carried out in a dynamic system established that the solid components acted as true acid catalysts, whereas the liquid fractions were inactive under the experimental conditions adopted. The catalytic activity per weight of the condensate exceeded that of either the parent clay or the extract.The present results confirm that colloidal size catalysts of high activity can be generated from clays. Such materials, mobilized and transported alone or with formation fluids, may act as catalysts in places removed in space and time from their source. This finding refutes objections previously raised to the operation of bulk clays as catalysts for reactions with particulate organics and supports the concept that acid catalysts derived from clays may participate in organic geochemical reactions in an aqueous medium.

Kinetics of the reaction of OH radicals with a series of esters under simulated conditions at 295 K

The rate constants of the isopropyl acetate, n-propyl acetate, isopropenyl acetate, n-propenyl acetate, n-butyl acetate, and ethyl butyrate reactions with OH radicals were determined in purified air under atmospheric conditions, at 750 torr and (295 ± 2) K. A relative rate experimental method was used; n-heptane, n-octane, and n-nonane were the reference compounds, with, respectively, rate constants for the reaction with OH of 7.12 × 10−12, 8.42 × 10−12, and 9.70 × 10−12 molecule−1 cm3s−1. The following rate constants were obtained in units of 10−12 molecule−1 cm3s−1; isopropyl acetate, (3.12 ± 0.29); n-propyl acetate, (1.97 ± 0.24); isopropenyl acetate, (62.53 ± 1.24); n-propenyl acetate, (24.57 ± 0.24); n-butyl acetate, (3.29 ± 0.35); and ethyl butyrate, (4.37 ± 0.42). Tertiary butyl acetate has a low reactivity with OH radicals (<1 × 10−12 molecule−1 cm3s−1). © 1996 John Wiley & Sons, Inc.

Complete life cycle of the canid tapeworm, Echinococcus multilocularis , in laboratory rodents

Mongolian gerbils, Meriones unguiculatus, when treated at intervals of 2-6 days with prednisolone tertiary butyl acetate, sustained infection with adult Echinococcus multilocularis in the small intestine, with the tapeworm exhibiting normal strobilation and egg production as in the natural canid host. Host age is critical for the survival of the tapeworm in normal gerbils; parasites survive for only 2 days in 20-wk-old animals, 4 days in 4-wk-old animals, but at least 7 days in 3-wk-old animals. The host age dependence in parasite recovery between days 28-37 postinfection was not affected by treatment from around the day of infection. Starting the treatment before infection (on day -17 relative to infection) remarkably improved the tapeworm's survival within the intestine of older animals. Eggs produced in this rodent model system 28 days postinfection were infective to rodents such as Mongolian gerbils and gray red-backed voles, Clethrionomys rufocanus bedfordiae, by oral or intraperitoneal inoculation. The E. multilocularis/Mongolian gerbil system can replace the natural canid hosts as a new way to obtain infective eggs and to analyze host-parasite interactions. The development of an alternative definitive host for zoonotic tapeworms may accelerate experimentation in this field.

The local anti-inflammatory activity of rimexolone (Org 6216) in fibrin-induced monoarticular arthritis and adjuvant-induced arthritis.

The effects of a number of steroids administered intra-articularly in a chronic model of fibrin-induced monoarticular arthritis in the rabbit have been investigated. Org 6216 hydrocortisone acetate, prednisolone tertiary butyl acetate and triamcinolone hexacetonide each suppressed the joint swelling produced 14 days after antigen challenge. These anti-inflammatory effects lasted for at least 7 days. Hydrocortisone semisuccinate was inactive in this model. In addition, the effects of the same compounds and several other anti-inflammatory steroids and indomethacin administered locally with adjuvant was assessed on the resultant paw oedema produced in the rat. The local anti-inflammatory activity, the duration of action and the systemic effects of these drugs varied considerably and only Org 6216, hydrocortisone acetate, prednisolone tertiary butyl acetate and indomethacin produced anti-inflammatory effects throughout the 4 days of the experiments and were devoid of significant adrenolytic and thymolytic activity.

Renal polycystosis in the rat induced by prednisolone tertiary butyl acetate.

A single i.m. injection of 66 mg/kg prednisolone tertiary butyl acetate given on the 1st day of life produced glomerular degeneration and collecting duct and proximal tubule cysts in rat kidneys. There was evidence of delayed nephrogenesis leading to persistance of the neogenic zone.

Non-faradaic electrocatalysis: Part I. Acceleration of ester hydrolysis in the electrochemical double layer

Pulsation of potential of a gold electrode in the double-layer region, between the p.z.c. and a several hundred millivolts more positive value, was found to increase the rate of hydrolysis of tertiary butyl acetate. The homogeneous rate constant of hydrolysis at 35°C was found to be 1.4×10 −6 s −1 in the absence of the electric field imposed by pulsation, while in the presence of the field at the ratio of the electrode surface area to the volume of reacting solution of 0.08 cm −1, it was found to be up to 7.2×10 −5 s −1 indicating a heterogeneous rate constant of 9×10 −4 s −1 cm −2. Effects of changing the potential limits, the frequency of pulsation and the ratio of time intervals during which the electrode has been maintained at one or the other potential limit have been recorded. The same effects are found when gold was replaced by silver. Tertiary butyl acetate is known to undergo hydrolysis by bond breaking between oxygen and tertiary carbon atom and the formation of a carb-cation radical intermediate. It is assumed that the catalytic effect is due to the polarisation of the adsorbed and suitably oriented molecules along the bond in the high electric field acting upon it in the Helmholtz layer during the potential pulse. The process is a non-faradaic one since no charge is transferred across the double layer.

The effect of single and of multiple doses of prednisolone tertiary butyl acetate on cell population kinetics in the small bowel mucosa of the rat.

The effect of single and of multiple doses of prednisolone upon cell population kinetics in the rat jejunal crypt was investigated, using autoradiography and stathmokinetic techniques with vincristine. Single injections of prednisolone (2.5 mg/kg body weight) induced a depression both flash thymidine labelling and mitotic indices; this change was shown to be due to a decreased cell production rate. Recovery of these proliferative indices occurred over seven days after injection; measurement of crypt size parameters showed a transient decrease in crypt population. Multiple daily injections of prednisolone (1 mg/kg body weight) produced a more sustained decrease in labelling and mitotic indices, which lasted as long as injections were continued (7 days); stathmokinetic techniques showed decreases in cell production rates, and the crypt population was also depressed throughout this period. It is concluded that prednisolone depresses cell proliferative rates in rat jejunal mucosa.

Plasma Protein Shedding by the Canine Oxyntic Glandular Mucosa Induced by Topical Application of Snake Venoms and Ethanol

A single irrigation of the mucosa of a pouch of the oxyntic glandular mucosa of a dog’s stomach with a dilute (0.5 mg per ml) solution of lyophilized venom of the hooded cobra (Naja rtaja) breaks the gastric mucosal barrier, but shedding of plasma does not occur. Twenty to 40 days later a similar irrigation with cobra venom solution causes a very large (sometimes more than 30 ml in 30 min) shedding of plasma through the mucosa. This plasma shedding builds up after the initial irrigation with or without frequently repeated irrigation of the mucosa with cobra venom solution, and it declines from its peak in about 30 days, leaving various degrees of residual plasma shedding. When the response has declined essentially to zero, irrigation with cobra venom solution still breaks the gastric mucosal barrier. Treatment of the dog with prednisolone tertiary butylacetate (1 mg per kg intramuscularly a day for 7 to 14 days) attenuates but does not abolish plasma shedding during irrigation with cobra venom solution. Irrigation of the mucosa with ethanol (30% v/v) also causes plasma shedding whether the mucosa has previously shed plasma in response to irrigation with cobra venom solution. Irrigation of a pouch with a dilute solution (0.5 mg per ml) of lyophilized venom of a viper (Vipera russellt) does not in itself induce plasma shedding, but if the mucosa is irrigated with a solution of viper venom immediately after it has been irrigated with ethanol, a plasma shedding response may be induced. Induction of plasma shedding by irrigation of the mucosa with numerous other foreign proteins combined with various barrier breakers has not been achieved.

Comparative Toxicity of Dexamethasone and its Tertiary Butyl Acetate Ester After Topical Ocular Instillation in Rabbits

Comparative Toxicity of Dexamethasone and its Tertiary Butyl Acetate Ester After Topical Ocular Instillation in Rabbits

Halide alkoxides of beryllium

The reactions of beryllium alkoxides, Be(OR) 2, (where R = Et or Pr i ) with acetyl halide yields products with formulae, Be(OR)X· xROAc and BeX 2·2ROAc ( X = Cl or Br and x = 0.5−0.7). The reactions of beryllium chloride with esters, e.g., HCOOEt and ROAc, (R = Me, Et, Pr n , Pr i , Bu n and Bu sec. ) give diadducts. With tertiary butyl acetate however, beryllium acetate is the end product of the reaction.

Reactions of Uranium Tetrachloride with organic esters

AbstractUranium tetraacetate is always the end product when uranium tetrachloride is treated with excess of tertiary butyl acetate, even in cold. However, when uranium tetrachloride is made to react with other esters, the replacement of chloride groups by acetate groups was found to be in the order normal &lt; secondary &lt; tertiary, resulting in the formation of acetate derivatives.

Reactions of (i) Aluminium Tertiary Butoxide with Acetyl Bromide and (ii) Aluminium Tribromide with Tertiary Butyl Acetate

Reactions of (i) Aluminium Tertiary Butoxide with Acetyl Bromide and (ii) Aluminium Tribromide with Tertiary Butyl Acetate

Observations on the action of intraarticularly administered prednisolon tertiary butyl acetate (Codelcortone TBA) and methylprednisolon acetate (Depomedrone) in the normal rabbit knee joint. A vital microscopic and histologic study.

Observations on the action of intraarticularly administered prednisolon tertiary butyl acetate (Codelcortone TBA) and methylprednisolon acetate (Depomedrone) in the normal rabbit knee joint. A vital microscopic and histologic study.