Addition Of Tert-butyl Alcohol Research Articles

Purification of pectinases by three-phase partitioning

Three-phase partitioning was used to purify pectinases from Aspergillus niger and tomato by addition of tert-butanol in the presence of ammonium sulphate. The yields of 76% (Aspergillus niger) and 183% (tomato) and purifications of 10-fold (Aspergillus niger) and 9-fold (tomato) were obtained. The final purified enzyme enzyme from tomato showed a single band on SDS-PAGE with a molecular weight of 46 kDa.

1-Ethyl 4-(1,1-dimethylethyl) 2-(1,2,3,4-Tetrahydro-1,3-dimethyl-2,4-dioxopyrimidin-5-yl)butanedioate

The diester 2 was prepared by the addition of tert-butanol to 1 according to the reported procedure [1].[...]

Mechanistic Investigations Concerning the Aqueous Ozonolysis of Bromacil

Bromacil ozonolysis was examined to determine the mechanism of product formation in an effort to optimize a chemical-microbial remediation strategy for contaminated waters. Two debrominated products, 3-sec-butyl-5-acetyl-5-hydroxyhydantoin (II) (24%) and 3-sec-butylparabanic acid (III) (56%), and a dibromohydrin, 3-sec-butyl-5,5-dibromo-6-methyl-6-hydroxyuracil (IV) (20%), were formed. The latter compound, arising from HOBr addition to bromacil, reverted back to starting material, causing the treated solution to remain somewhat phytotoxic. Mass balance studies provided evidence for parallel reaction pathways as opposed to a series pathway where II gives rise to III. Addition of hydrogen peroxide slightly decreased the rate of bromacil degradation while the addition of tert-butyl alcohol (t-BuOH), a hydroxy radical scavenger, increased the degradation rate, strongly suggesting that the mechanism does not involve hydroxy radicals but direct ozone attack at the double bond. A much lower yield of IV, 6%, relative to the control was observed with H 2 O 2 , whereas a slightly higher yield, 23%, was found with t-BuOH.

Phase behaviour of lecithinwateralcoholtriacylglycerol mixtures

Although phospholipids, e.g. lecithin, are widely used to stabilize water-edible oil mixtures, so far the thermodynamic phase behaviour properties of such lecithin-containing blends have not been investigated systematically. The phase behaviour of a model system containing pure lecithin, i.e. phosphatidylcholine (PC), medium-chain triacylglycerol (MCT), water, and different types of C 3C 5 alcohols is studied in this paper. In the absence of alcohol, PC is dispersed in water-MCT mixtures as liquid crystals. Addition of alcohol decreases the rigidity of the PC bilayer structures and leads to the formation of isotropic phases. Moreover, depending on the type of alcohol, the spontaneous curvature of the surfactant monolayer is changed from zero, in the absence of alcohol, towards either negative values when forming microemulsion water droplets dispersed in an oil continuum, or to positive values by forming microemulsion oil droplets dispersed in an aqueous continuous phase. The results suggest that it is difficult to induce the formation of flexible monolayers having a zero net spontaneous curvature, a prerequisite for the formation of a bicontinuous microemulsion phase. In all likelihood, this is because addition of alcohol changes not only the rigidity but generally also the spontaneous curvature of the PC monolayers. An exception is observed on the addition of tert-butanol which induces the formation of a bicontinuous-type microemulsion middle phase. In this case, the bilayer rigidity seems to be decreased while maintaining a low spontaneous curvature. This is one of the few cases reported up to now which show microemulsion formation as encountered when using mineral oils, containing comparable amounts of oil and water.

Time resolved ESR spectroscopy. II. The behavior of H atom signals

The time dependence of the ESR signals of H atoms formed in acid water by pulse radiolysis has been examined at times >2 μsec after the pulse. As in steady-state experiments, the two lines are of very similar amplitudes but with the low-field line appearing in emission. A growth of signal is observed for the first 4–10 μsec depending upon the microwave power and dose per pulse. At the higher microwave powers (>1 mW) an oscillatory decay is observed which must be caused by the transient response of the spin system. An attempt has been made to explain the over-all behavior of the ESR signals by introducing the assumption that the signal enhancement arises upon nuclear spin dependent recombination. This effect is included in the Bloch equations by a production term for Mz which is proportional to radical concentration (taken to decay by a second-order kinetic curve). The results of this calculation were very successful in fitting all details of the observed curves including the initial growth and the oscillatory behavior. An alternative assumption, that the singal enhancement occurred upon radical formation, did not lead to agreement with the observations. Because the initial growth is a direct consequence of the Bloch equations it is not necessary to invoke any chemical complications, such as a precursor of lifetime ∼ 5 μsec, to explain this phenomenon. The ESR signals of H atoms in acid were found to double upon addition of tert-butyl alcohol as an OH scavenger, and a much larger fractional increase was found in neutral, N2O saturated water. These results are taken to show that the reaction H+OH is not selective as to the spin state of the H atom and so as a result produces no signal enhancement, while the reactions H+H and H+R do lead to signal enhancement.

Emulsion polymerization of ethylene. II. Effect of recipe on particle size and distribution

Particle diameters were measured in electron photomicrographs of polyethylene latexes prepared with a potassium soap, a polyethyoxylated p-alkyl phenol, or a sodium alkyl sulfate. The volume-surface average diameters calculated from these values compare well with those obtained independently by soap adsorption. Plots of the diameters on log probability paper indicate that the diameters follow a log-normal distribution. The width of the distributions is given, and its effect on the difference between the number-average and volume-surface average diameters is discussed. A study of the effect of the recipe shows that the diameter of the average particle produced in the emulsion polymerization of ethylene decreases as the amount of emulsifier is increased, but the addition of tert-butyl alcohol increases particle diameter. Particle diameter is not affected by the initiator within the concentration range normally used. During the course of polymerization, the number of particles slowly increases in the presence of tert-butyl alcohol, but in its absence the number of particles decreases. In the absence of tert-butyl alcohol, the number of particles increases as the 1.1 power of the emulsifier concentration.