Methyl isobutylketone

A number of techniques have been developed for the trace analysis of siUcones in environmental samples. In these analyses, care must be taken to avoid contamination of the samples because of the ubiquitous presence of siUcones, particularly in a laboratory environment. Depending on the method of detection, interference from inorganic siUcate can also be problematic, hence nonsiUca-based vessels are often used in these deterrninations. SiUcones have been extracted from environmental samples with solvents such as hexane, diethyl ether, methyl isobutylketone, ethyl acetate, and tetrahydrofuran (THF)... 

The ketimine of isophorone diamine is formed by reacting it with methyl isobutylketone, splitting off water in the process. When said ketimine is added to an isocyanate-terminated prepolymer based on IPDI, a semi-stable system is established with a pot life of several hours. The ketimine is a Schiff base and thus can react even in the absence of water. The complexities and advantages of this system are reviewed by Bock and Halpaap [75] ... 

The principle Zr ore, zircon (Zr silicate) is processed by caustic fusion or by direct chlorination of milled coke and zircon mixts. Washing of the Na fusion cake leave an acid soluble hydrated Zr oxide, whereas chlorination yields mixed Si and Zr tetrachlorides which are separated by distillation. Removal of the Hf from the Zr takes place through counter current liq-liq extraction (Ref 33), For this purpose the oxide or the tetrachloride is dissolved in dil hydrochloric acid to which ammonium thiocyanate is added as a complexing agent. The organic extracting phase is methyl isobutylketone... 

To a solution of 4-amino-5-chloro-2-methoxybenzoic acid (20.2 g) in methyl isobutylketone (250 ml) and triethyl amine (15.3 ml) was slowly dropped ethyl chloroformate (9.6 ml). The reaction mixture was stirred for 30 min at room temperature. To the formed mixed anhydride was then added l-[3-(4-fluorophenoxy)-propyl]-3-methoxy-4-piperidinamine (28.2 g) and the reaction mixture was stirred for 2 hours at room temperature. Subsequently, the reaction mixture was washed with water (80 ml) and a NaOH solution (6.5% w/v, 50 ml). The organic layer was warmed to 65°C and methanol (50 ml) and water (8.5 ml) were added. The solution was cooled slowly and stirred for 2 days during which crystallisation occurred, yielding benzamide, 4-amino-5-chloro-N-(l-(3-(4-fluorophenoxy)propyl)-3-methoxy-4-piperidinyl)-2-methoxy-, monohydrate, cis- (Cisapride) having a cis/trans ratio higher than 99/1. 

Internal Standard Solution Dissolve about 100 mg of methyl isobutylketone, accurately weighed, in 10 mL of methanol contained in a 100-mL volumetric flask, dilute to volume with methanol, and mix. 

These often correspond to aromatic hydrocarbons (xylene, toluene, ethylbenzenes, etc.) and ketones (methyl-ethylketone, methyl-isobutylketone, methyl-propyl-ketone, etc.). 

Moderately polar solvents are preferred, e.g., methyl isobutylketone or dimethoxy-ethane. N,N-Dimethylformamide inhibits carbonylation by forming a stable Pt adduct incapable of olefin complexation. 

Solvent is chosen such that the compound of interest is neither excessively soluble nor insoluble. The common solvents include water, the short-chain alcohols (methanol to hexanol), halogenated solvents (chloroform and carbon tetrachloride), ketones such as acetone and methyl-isobutylketone, pyridine, 1,4-dioxane, ethyl acetate, diethyl ether, petroleum ether, hexane, and toluene. Solubility vanes tremendously with solvent. The solubility of naphthalene, for example, is approximately doubled going from methanol to ethanol, while the addition of water to either drastically reduces solubility (9). Thus, solvent selection is important, and solvent mixtures provide a convenient way of tailoring solubility to a required level. Any miscible pair of solvents is worth investigating, especially if compound solubility differs significantly between the two. 

Pipet 1 mL of methyl isobutylketone into the tube and homogenize again for 2 min. 

Methyl isobutylketone Normal paraffin hydrocarbon Polyethylenimine Penicillin G... 

Silicones have been extracted from environmental samples with solvents such as hexane, diethyl ether, methyl isobutylketone, ethyl acetate, and THF, using either sequential or Soxhlet techniques (690-695). Silicones of a wide range of molecular weights and polarities are soluble in THF. This feature, coupled with its volatility and miscibility with water, makes THF an excellent solvent for the extraction of silicones from wet samples, ie, soils and sediments. Trace levels of silicones extracted from environmental samples have been measured by a number of techniques, including atomic absorption spectroscopy (AA), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), pyrolysis GC-MS, as well as H and Si NMR spectroscopy (674,684,692,696-700). The use of separation techniques, such as gel permeation and high pressure liquid chromatography interfaced with sensitive, silicon-specific AA or ICP detectors, has been particularly advantageous for the analysis of silicones in environmental extracts (685,701-704). 

---