DE298944C - - Google Patents

Description

ISSUED DECEMBER 12, 1919

Of the processes given in the literature for the production of monobromoacetone Only the methods of N. Sokolowsky come primarily for technical utilization (see report of the German Chemical Society 1876, 9, p. 1687) and by Nef (Liebigs Annalen der Chemie 335, 1904, p. 259) into consideration.

N. Sokolowsky gradually adds bromine to an aqueous solution of acetone, which ■ contains 10 parts of water to ι part of acetone. This method has the drawbacks that when displaying with an extremely large j Liquid volume must work so that the j bromine therefore extremely slowly under large Loss of time must be entered in the acetone-water mixture, since the solubility of the Broms is very small, and that finally, if the reaction was insufficient, an accumulation would be suspended or bromine located at the bottom of the vessel occurs, which leads to smearing of the finished product leads ■■ to explosive reactions can give. In addition, the yield of bromoacetone is very unfavorable and polysubstitution products can be formed in place of the monobromine compound, as a result of the direct use of bromine. You get after this procedure an average of 110 Percent (theory 171 percent) crude bromoacetone (based on substituting bromine), which is a dark, partially smeared product represents considerable amounts (about 10 to 15 j Percent) multiple brominated acetone contains I and only cleaned by laborious methods must become.

According to the procedure of Nef, 100 g Acetone, 100 g glacial acetic acid and 400 g water mixed and the mixture 276 g bromine as well then added 200 g of water. Then the acidic solution with soda becomes almost perfect neutralized.

The yield of bromoacetone with respect to substituting bromine is 125 percent Raw product with 13 percent higher boiling parts. A major shortcoming of this procedure lies in the use of glacial acetic acid, which on the one hand makes the preparation very expensive, on the other hand easily causes smearing, while by rapidly adding the required Polysubstitution products are easily formed.

It has now been found that monobromoacetone can be obtained in the most favorable yield and without Aftertreatment is obtained in unprecedented purity if you take it at an elevated temperature a solution of bromine to a solution of acetone in brpmacetone-containing bromide liquors can flow in aqueous bromide solutions. The bromide liquors that were previously obtained as waste products by neutralization are used here Alkalis from earlier bromacetone preparations used. As from the same If the concentration is too high, the bromide crystallizes out by itself when it cools, so can these alkalis are used continuously; moreover, their exploitation grants to that extent still significant advantages when they are saturated with bromoacetone and still significant

Claims (1)

Contain amounts of excess acetone applied. .. to be used to solve the bromine also used the 'bromide lies, after -: ./ that she. if necessary by i-.to boil .and Treatment with steam freed most of the bromoacetone and acetone have been. By using bromobromide solutions on the one hand and bromoacetone-containing ίο Acetone bromide liquors on the other hand, as well as-by the increased temperature becomes so rapid that it spreads over the entire volume of liquid: partial bromination of acetone ensures that manufacture, even in the absence of one Agitator 'goes on smoothly and one- at much higher concentrations can work without smearing or other deterioration of the end product fear too. have to. It is therefore an essential part of the present proceedings. lent progress. The method by Fritsch (report of the German Chemical Society 29, 1895, p. 1555) is out of the question here. After this, bromine vapor mixed with air is passed into acetone, which contains pieces of marble, while a certain amount of water flows in at the same time. Although a certain amount of calcium bromide is present in the solution towards the end of the illustration, the purpose of using the marble is merely to neutralize the hydrogen bromide that is formed during the course of the reaction. Author has favorably 'influencing' the reaction between bromine and. Acetone by the application of bromide lies. neither recognized nor brought to the exploitation, otherwise he would have had to use one hand bromide solutions already at the beginning, on the other hand not bromine vapor with air diluted apply ■ -the sludge. : '■;_;; i :; Example: 320 g of acetone with 1 · 1 saturated with bromoacetone sodium or calcium bromidlauge of about 30 to 40 ° Be mixed, the mixture was heated run 60 to 70 ⁰ and then in a thin stream a solution of 800 g of bromine in ι Γ ( acetone-: and bromoacetone-free bromide liquor? allowed to flow. The monobromoacetone separates out as an oily liquid on the bottom of the vessel. The supernatant liquid is then neutralized with calcium carbonate or soda to precipitate the bromoacetone as completely as possible, and the finished product is drained, washed out and dried. . . ■■. The bromoacetone obtained is a clear, reddish liquid; D ₁₀ 1.988; Br content 57.62 percent (calculated 58.40), yield 662 g (= 165 percent based on subst. Bromine). The bromoacetone should either be used as such or as an important starting material] serve for technical purposes. \ Patent Claim :; ^: . ■ '■■' ■■ : ·? .Ν, Process for the production of.rmono-. ■ bromoacetone / characterized; that at elevated temperature .. _: solutions. from bromine in bromide leaches to bromoacetone-containing solutions of acetone in., bromide leaches and as bromide leaches, .. the neutralized aqueous lyes of earlier,. Bromacetone representations used. .. ,,., ..;. ■.