4-Methylpentane-2,3-diol

Thermally stable AI2O3 was synthesized as in ref. 5, by hydrolysis of A1 isopropoxide (99.99+% Aldrich Chemicals) dissolved in 2-methylpentane-2,4-diol. The resulting solid was filtered, washed in 2-propanol, and dried in air at 373 K. Then, it was calcined in flowing dry air, while the temperature was raised at 1 K/min to 733 K, when 2.4% HjO was introduced to the flowing air. Afterwards, the temperature ramp was continued to 973 K. The sample was kept at 973 K for 2 h in 7% water. The isoelectric point of the resulting y-Al Oj was pH 8. The BET surface areas were 205 to 235 mVg, and the average pore size radius was around 8.3 nm... 

Aznarez et al. [2] have described a Spectrophotometric method using curcumin as chromopore for the determination of boron in soil. Boron is extracted from the soil into methyl isobutyl ketone with 2-methylpentane-2,4-diol. In this method 0.2-lg of finely ground soil is digested with 5ml concentrated nitric-perchloric acid (3 + 1) in a polytetrafluoroethylene lined pressure pump for 2h at 150°C. The filtrate is neutralized with 6M sodium hydroxide and diluted to 100ml with hydrochloric acid 1+l.This solution is triple extracted with 10ml of methyl isobutyl ketone to remove iron interference. This solution is then extracted with 10ml 2-methyl pentane-2,4 diol and this extract dried over anhydrous sodium sulphate. 

H, Cl, Br, NO2, Me, MeO) by bromamine-B, catalysed in the presence of HCl in 30% aqueous methanol by RuCls have been smdied and a biphasic Hammett a-relationship derived. A kinetic study of the ruthenium(in)-catalysed oxidation of aliphatic primary amines by sodium A-bromo-j -toluenesulfonamide (bromamine-T, BAT) in hydrochloric acid medium has been undertaken and the mechanism of the reaction discussed. A concerted hydrogen-atom transfer one-electron transfer mechanism is proposed for the ruthenium(in)-catalysed oxidation of 2-methylpentane-2,4-diol by alkaline hexacyanoferrate(III). The kinetics of the oxidation of propane-... 

Table 15.2 Crystallization conditions for DNA-protein complexes using 2-methylpentan-2,4-diol (MPD) as a precipitant... 

Tyrrell and Watkiss [58] showed that the numerical coefficient for 2-methylpentan-2,4-diol solvent is not 6 or 4 but nearer 1—3 depending on the solute molecular size and shape and temperature, being smaller for smaller and planar molecules. In a study of normal alkanes, Amu [59] found that this numerical factor decreased as the molecular chain length increased. Indeed, if the solute molecules are significantly different from a spherical shape, the diffusion coefficient should be regarded as (a tensor) having different values in different directions. Usage of the microfriction factor mentioned in Sect. 5.2 is an improvement, but still rather unsatisfactory (Alwatter et al. [43]). 

The reactions of butane-2,3-diol by HCF in alkaline medium using Ru(III) and Ru(VI) compounds as catalysts leads to similar experimental rate equations for both the reactions. The mechanism involves the formation of a catalyst-substrate complex that yields a carbocation for Ru( VI) or a radical for Ru(III) oxidation. The role of HCF is in catalyst regeneration. The rate constants of complex decomposition and catalyst regeneration have been determined.89 A probable mechanism invoving formation of an intermediate complex has been proposed for the iridium(III)-catalysed oxidation of propane- 1,2-diol and of pentane-1,5-diol, butane-2,3-diol, and 2-methylpentane-2,4-diol with HCF.90-92 The Ru(VIII)-catalyzed oxidation some a-hydroxy acids with HCF proceeds with the formation of an intermediate complex between the hydroxy acid and Ru(VIII), which then decomposes in the rate-determining step. HCF regenerates the spent catalyst.93... 

Aznarez et al. [2] also applied molecular fluorescence spectroscopy to the determination of borate in soils. The boron is extracted from the soil with 2-methylpentane-2,4 diol into methyl isobutyl ketone and 0.1% m/v diben-zoylmethane in methyl isobutyl ketone and concentrated phosphoric acid is... 

Where the glycol contains one or two secondary or tertiary hydroxyls, the products are more soluble and some are even monomeric cyclic chelates (65,66). Three compounds are obtained from 2-methylpentane-2,4-diol, depending on the mole ratio (67—70). Structure (3) represents an isolable but labile aLcoholate of (2)... 

METHYLPENTANE-2,4-DIOL (107-41-5) Forms explosive mixture with air (flash point 204°F/96°C). Incompatible with sulfuric acid, nitric acid, caustics, aliphatic amines,... 

Selection of the solvent was another problem. Since it was expected that a high viscosity would be required to invalidate TST in these reactions, three viscous liquids with different functional groups were chosen, namely, 2,4-dicyclohexyl-2-methylpentane (DCMP) as a non-polar solvent, glycerol triacetate (GTA) as a polar aprotic solvent, and 2-methylpentane-2,4-diol (MPD) as a protic solvent. All these solvents have a branched molecular structure and, therefore, the shear viscosity y increases much more rapidly with increasing pressure than in common solvents. The pressure effects on rj of MPD are shown in Fig. 3.3. As can be seen from this figure, the pressure dependence of rj could be approximately expressed by... 

The cyclic arsenosilicate compound, 4,4,6-trimethyl-2-(triphenylsilyloxy)-l,3,2-dioxarsinane 60, has been synthesized using a one-pot reaction between triphenylsilanol 61, AS2O3, and 2-methylpentane-2,4-diol 62 in a 2 1 2 molar ratio (Scheme 20) <2003ARK255>. 

Recently, strikingly new results were obtained with a biopolymer, in which a natural wool carrier combined with PdCb in EtOH to form catalytic complexes (Yin et al. These catalysts hydrogenated diacetone alcohol (4-hydroxy-4-methylpentan-2-one) into (R)-2-methylpentan-2,4-diol and 3-methylbutan-2-one into (R)-3-methylbutan-2-ol (Scheme 3.9.) with ee s of 73% and 100%, respectively. These catalysts could be used repeatedly without decreasing enantioselectivity. 

Methyl-2,4-pentanediol 2-Methylpentane-2,4-diol 4-Methyl-2,4-pentanediol. See Hexylene glycol 2-Methylpentanol. See 2-Methyl-1 -pentanol... 

A decrease in the number of microtubnli has been observed in bovine pituitary sUces incubated with two non-physiological stimulants, extracellular barium and 3-isobutyl-1-methylxanthine of growth hormone secretion (Sheterline et al. 1977). Both growth hormone secretion and depolymerization were prevented by 2-methylpentan-2,4-diol, a microtubule stabiUser. 

Reeves and Mazzeno as early as 1954 studied cryoscopically the reactions of Ti(OBu )4 with various glycols in tertiary butyl alcohol and observed that the products were not simple monomers but were associated species having the titanium to glycol ratio 2 3, 4 6, 2 2, and 3 6 (Ti2(OBu )2(glycolate)6). Yamamoto and Kambara carried out the reactions of titanium tetra-aUcoxides with excess of 2-methylpentane-2,4-diol and isolated a product of the type Ti(0CHMeCH2CMe20)2.(H0CHMeCH2CMe20H). 

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