Monoethylation

Cellosolve A trade name for ethylene glycol monoethyl ether. Also known as Oxitol. 

Homologous mono-alkyl ethers of ethylene glycol, such as monoethyl glycol (or 2-ethoxyethanol), HOC2H4OC2H5, form excellent solvents as they combine to a large extent the solvent properties of alcohols and ethers. The monoethyl and the monomethyl members have the technical names of ethyl cellosolve and methyl cellosolve respectively. Dioxan... 

It is now applied more widely to include malonic acid derivatives, such as diethyl monoethyl-malonate, ethyl cyanacetate, etc. Various amines may be used as catalysts, and usually the most effective is piperidine (hexahydro-pyridine) a mixture of piperidine and pyridine, or pyridine alone, is also often used. 

Note on the laboratory preparation of monoethylaniline. Although the laboratory preparation of monomethyl- or monoethyl-aniline is hardly worth whUe, the following experimental details may be useful to those who wish to prepare pure monoethylaniline directly from amline. In a flask, fitted with a double surface reflux condenser, place 50 g. (49 ml.) of aniline and 65 g. of ethyl bromide, and boU gently for 2 hours or until the mixture has almost entirely sohdified. Dissolve it in water and boil off the small quantity of unreacted ethyl bromide. Render the mixture alkaUne with concentrated sodium hydroxide solution, extract the precipitated bases with three 50 ml. portions of ether, and distil off the ether. The residual oil contains anihne, mono- and di-ethylaniline. Dissolve it in excess of dilute hydrochloric acid (say, 100 ml. of concentrated acid and 400 ml. of water), cool in ice, and add with stirring a solution of 37 g. of sodium nitrite in 100 ml. of water do not allow the temperature to rise above 10°. Tnis leads to the formation of a solution of phenyl diazonium chloride, of N-nitrosoethylaniline and of p-nitrosodiethylaniline. The nitrosoethylaniline separates as a dark coloured oil. Extract the oil with ether, distil off the ether, and reduce the nitrosoamine with tin and hydrochloric acid (see above). The yield of ethylaniline is 20 g. 

Experiments with monoethyl and monocarbomethoxy di- -xyljlene (4) gave similar results. These experiments do not, however, shed any light on whether the mpture of the methylene—methylene bonds in the dimer upon pyrolysis is simultaneous or sequential. 

Lurgi oHdi-none (NMP) water (12—20) or monoethyl-ene glycol (40—50 wt %) must be added to the NMP to increase the selectivity and to decrease the boiling point of the solvent the NMP—water proc-esses use pentane countersolvent NMP—water, 35 mix-ter—setder, 24—30 stages, up to 8 m in diameter component required depends on the aromatics content of the feed... 

Activators. Activators are often added to removers to make them more efficient. Acids such as phenol [108-95-2] phosphoric acid [7664-38-2] acetic acid [64-19-7] formic acid [64-18-6]., and citric acid [5949-29-1] are used to increase the cutting abiHty on epoxide-type paints and other modem finishes. Strongly alkaline activators are effective on enamel andlatex paints. Other activators include ammonia [7664-41-7] monoethyl amine [75-04-7], and /V-phenyIdiethan ol amines. Acid and base activators shorten the shelf life of some removers. 

The rate of stripping or the stripabiUty on cataly2ed urethane and epoxy resin finishes can be increased by adding formic acid, acetic acid, and phenol. Sodium hydroxide, potassium hydroxide, and trisodium phosphate [10101-89-0] may be added to the formula to increase the stripabiUty on enamel and latex paints. Other activators include oleic acid [112-80-17, trichloroacetic acid [76-85-9], ammonia, triethanolamine [102-71-6], and monoethyl amine. Methylene chloride-type removers are unique in their abiUty to accept cosolvents and activators that allow the solution to be neutral, alkaline, or acidic. This abihty gready expands the number of coatings that can be removed with methylene chloride removers. 

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