Isobutyric acid and water

Figure 6. The effective susceptibility exponent as a function of AT for xenon (Xe), for isobutyric acid and water (IBAW), for 3-methylpentane and nitroethane (3MPNE) [20], for two 3MP+H20-j-NaBr samples with 8 mass % and 16 mass % NaBr [28], for a nonaqueous ionic solution of tetra-u-butyl ammonium picrate in 1,4-butane-dion/l-dodecanol (0.75/0.25) (TPDB) [20], and for two samples of polystyrene in deute-rocyclohexane with molecular weight 28 (PSl) and 200 (PS4) [24]. From Ref. [53].

Figure 9. Scattered light intensity / (arbitrary units) as a function of wave vector k and time t for a critical mixture of isobutyric acid and water quenched into the unstable region, k = 47tn/k) sin (6/2), where n is the refractive index, A is the wavelength of the incident beam, and 6 is the scattering angle [122, 5].

Knobler, C.M., and N.-C. Wong (1981) Light scattering studies of phase separation in isobutyric acid and water mixtures. 2. Test of scaling, J.Phys. Chem. 85, 1972. 

This paper deals with the synthesis of propionic acid by the reaction of carbon monoxide, ethylene, and water and the synthesis of isobutyric acid and 2-methylbutyric acid by the reaction of carbon monoxide with n-propyl alcohol and n-butyl alcohol, respectively, in presence of nickel catalysts at high pressures. 

The nickel iodide-silica gel catalyst which was highly active at a given temperature and pressure became progressively deactivated when exposed to the same temperature at atmospheric pressure. Thus, in three successive experiments carried out at 230° and 6000-p.s.i.g. pressure, with the same sample of the catalyst the yields decreased in the order 41.0,24.6, and 16.4 % in the case of isobutyric acid, and in the order 38.4, 20.1, and 12.6% in the case of 2-methylbutyric acid, when the catalyst was exposed to the reaction temperature at atmospheric pressure for a few hours at the conclusion of each run. However, the addition of a few drops of cold water on the surface of the partly deactivated catalyst was found to restore its original activity completely. It was found possible to maintain the activity of the catalyst indefinitely in the presence of a small quantity of water, provided the... 

Transfer 10.73 g (0.005 mol) 2-(p-cbloropbenoxy) isobutyric acid and 5.6 g (0.025 mol) 7-bydroxy etbyltbeopbylline were suspended together in 25 ml xylene in a 100 ml round bottom flask. The resulting mixture was heated together for almost 15 hours at a stretch in a water-separator following the addition of 0.15 g p-toluenesulphonic acid. 

The basic product of the reaction is 2-methyl-butane-3-one (methylisopropyl ketone) in the absence of water, whereas pivalic acid represents the basic product in the presence of water at 70°C and 8 atm partial CO pressure. Conversion of alkane (36%) was reached at 1 h of the reaction time vmder conditions of batch reactor (81). Under similar conditions n-pentane converts into a mixture of Ce-aldehydes [2-ethyl-butyraldehyde (5%), 2-methyl-pentanaldehyde (3%)] and ketones [2-methyl-pentane-3-one (11%) and 3-methyl-pentane-2-one (5%)] at 24% total conversion of n-pentane (82). In the presence of water n-pentane gives a mixture of three acids 2-ethyl-butjrric acid, 2-methyl-pentanoic acid, and 2,2-dimethyl-butyric acid at 150-200°C, 10 atm CO pressure, and 20% total n-pentane conversion. Carbonylation of propane gives rise to a mixture of isobutyric acid and isobutyraldehyde at 150°C, 10 atm CO pressure, and 22% propane conversion, isobutyric acid being the main product. 

Isobutyric acid, dimethylacetic acid, 2-methylpropanoic acid, (CHjjjCH COOH, colourless syrupy liquid with an unpleasant odour b.p. 154°C. Prepared by oxidation of 2-methylpropanol with K2Cr207 and H2SO4. Salts soluble in water. Used in alkaline solution for sweetening gasoline. 

The monoisobutyrate ester of TMPD, Texanol, or Filmer IBT, formally an isobutyraldehyde trimer, is prepared in a single step from isobutyraldehyde or, alternatively, by the esterification of TMPD with isobutyric acid. This monoester is most commonly employed as a coalescing agent for latex-based paints and water-based ink formulations. 

A mixture of 22 grams of Oi-(p-chlorophenoxy)isobutyric acid, 3.8 grams of 1,3-propane-dioi, 0.5 gram of p-toiuenesulfonic acid and 150 ml of xylene was refluxed. When the theoretically calculated amount of water had been removed, the xylene solution was washed with dilute aqueous sodium bicarbonate and then the xylene was distilled off. The residue was distilled under reduced pressure to give 11 grams (47% yield) of 1,3-propanediol bis[a-(p-chlorophenoxy)isobutyrate] boiling at 197° to 200°C/0.03 mm Hg. 

Kemp and Waters found a primary kinetic isotope effect of 8.7 for oxidation of C-deuterated mandelic acid and noted a large difference in rate between the oxidations of mandelic acid k at 24.4 °C = 1.7 l.mole . sec ) and a-hydroxy-isobutyric acid ( 2 at 24.4 °C = 5.6 x 10 l.mole . sec ) — a difference not reproduced for the oxidation of these compounds by the one-equivalent reagent, manganic sulphate. The various data are fully in accord with a Westheimer-type mechanism, viz. 

A modified nucleotide found in RNA sequencing could either be a new nucleotide of unknown chemical structure or it could correspond to an already known modified nucleotide (up to now about 90 different modified nucleotides have been identified in RNA). Keith [124] proposed preparative purifications of major and modified ribonucleotides on cellulose plates, allowing for their further analysis by UV or mass spectrometry. Separation was realized by two-dimensional elution using the following mobile phases (1) isobutyric acid-25% ammonia-water (50 1.1 28.9,... 

The specific rates of hydrolysis of five organic halides in three water-based liquid mixtures near their respective equilibrium consolute points have been observed to be suppressed. The systems studied included t-amyl chloride in isobutyric acid water (upper consolute temperature), and 3-chloro-3-methylpentane in 2-butoxyethanol water (lower consolute temperature). The slowing effect occurred within a few tenths of a degree on either side of the consolute temperature. 

Carboxylic acids can also be formed by a reaction of small alkanes, carbon monoxide, and water on solid acid catalysts (93,94). By in situ C MAS NMR spectroscopy (93), the activation of propane and isobutane on acidic zeolite HZSM-5 was investigated in the presence of carbon monoxide and water. Propane was converted to isobutyric acid at 373 73 K, while isobutane was transformed into pivalic acid with a simultaneous production of hydrogen. On SZA, methyl isopropyl ketone was observed as evidence for the carbonylation of isobutane with carbon monoxide after the sample was held at 343 K for 1 h (94). When the reaction of isobutane and carbon monoxide was carried out in the presence of water, pivalic acid was identified as the main reaction product (94). These observations are rationalized by the existence of a small number of sites capable of generating carbenium ions, which can be further trapped by carbon monoxide (93). 

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