DE1015803B - Process for the production of cumene hydroperoxide by oxidation of pre-purified cumene - Google Patents

Description

GERMAN

The invention relates to the per se known oxidation of cumene.

Molecular oxygen, e.g. B. pure oxygen gas or a gas mixture containing oxygen, e.g. B. air, is used, the cumene to be oxidized in liquid state.

The cumene hydroperoxide can, for. B. as a polymerization accelerator, as a catalyst for the conversion of macromolecular compounds, such as rubber, with sulfur dioxide (cf. German patent specification 813 893) and as an intermediate product in the manufacture of various products, e.g. B. the corresponding Alcohols (see US Pat. No. 2,491,926), but especially of phenolic compounds to serve.

Cumene can easily be made by alkylating benzene.

In general, it is believed that the aforementioned reaction is a chain reaction involving is free radical. In the light-up time, the reaction speed is slow, but increases gradually, until a sufficient number of reaction chains has arisen to reduce the concentration of free Maintain radicals through constant regeneration. Impurities in the cumene often exert a Inhibition on the oxidation. In some cases the inhibitory effect is so strong that it is almost it is impossible to start the oxidation, but sometimes the inhibitor becomes gradual decomposes, or after some time an increasing number of the free radicals formed acts more or less opposed to the inhibitor. The reaction speed then remains for quite a long time very low and only increases more strongly very late.

Various substances have already been added to cumene, which promote the formation of hydroperoxide, z. B. Catalysts or start-up means that shorten the start-up time and / or the influence counteract the inhibiting substances, or in some cases stabilize the hydroperoxide before decomposition protection.

It was to be expected that the inhibition of peroxide formation by thorough cleaning of the cumene can at least largely be insulated. In many cases, however, there is even one careful cleaning inadequate, either because some inhibitors are very difficult to remove or because there are other influences that have not yet been taken into account.

The inhibition is particularly to be observed if technically crude cumene is used or such, obtained from solutions of the corresponding hydroperoxides in aromatic hydrocarbons

Method of manufacture

of cumene hydroperoxide by oxidation

of prepurified cumene

Applicant:

NV De Bataafsche Petroleum
Maatschappij, The Hague

Representative: Dr.-Ing. F. Wuesthoff, Dipl.-Ing. G. Pulse

and Dipl.-Chem. Dr. rer. nat. > E. Mr. from Pechmann,

Patent Attorneys, Munich 9, Schweigerstr. 2

Claimed priority:
Netherlands of 23 August 1951 and 29 February 1952

Johan Michael Goppel and Gottfried Ernst Rumscheidt,

Amsterdam, Netherlands),
have been named as inventors

although in the latter case the amount of contamination depends very much on the purpose, which these solutions have served and the procedures that have been followed in using them. The method described in German Patent 813 893 leads, for. B. to a very annoying one Contamination of the recovered aromatic hydrocarbons.

Some procedures have been described in the literature to deal with aromatic hydrocarbons to make more easily oxidizable, e.g. B. refluxing for 8 hours in the presence of metallic Sodium with subsequent fractionation (H ο c k and Lang, reports of the Deutsche Chemischen Gesellschaft, Vol. 77, 1944, footnote on p. 261), washing with aqueous sodium bisulfite solution or Potassium permanganate solution (UK Patent 610 293, p. 4, lines 29-32).

According to the method of British patent specification 649 286, interfering styrene compounds can be found Cumene can be removed by distillation with subsequent hydrogenation while following the procedure British Patents 626 095 and 630 286 aromatic hydrocarbons with sulfuric acid and / or alkali permanganate solution are washed in order to increase their oxidizability.

It has now been found that the treatment of cumene according to the invention its oxidizability, un-

709 637/430

depending on its manufacturing process, significantly improved.

The cumene is z. B. 1 to 30 minutes with the hydrogen fluoride in an amount between 0.1 and 10 percent by weight, preferably about 5 percent by weight, based on cumene, stirred.

The treatment with hydrogen fluoride with stirring according to the invention gave good results with cumene, making it easily oxidizable. In some cases, as was found, there is a follow-up treatment with an aqueous mercuric salt solution, preferably mercuric acetate solution (cf. German patent 956 945). It is usually less beneficial to have treatment with Mercuric salt solution to begin.

The invention is illustrated in the following example. All percentages are percentages by weight.

example

500 g of technical cumene were mixed with 25 g of hydrogen fluoride for 10 minutes at room temperature Treated stirring in an iron kettle. After the delamination, the remaining cumene became washed with 11 10% strength sodium hydroxide solution cooled to 0 °. It was then almost neutral against litmus. It was finally distilled four times with 0.5 liters Water washed.

200 ecm of this cumene were below at 120 ° Passing through moist air in the presence of 3% cumene hydroperoxide, based on the amount used Cumene as a starting agent, oxidized at a rate of 9 liters of air per hour. The amount of hydroperoxide was determined iodometrically. The result is shown in the following table.

Oxidation duration Cumene hydroperoxide concentration in% treated in hours untreated Cumene Cumene 3.0 0 3.0 7.0 1 6.5 13.4 2 Q O
Ο, Δ 20.7 3 8.5 23.8 4th 8.7 24.7 5 - 34.8 6th -

Crude technical cumene obtained by alkylation of benzene was used with a reflux ratio rectified by 20: 1 (30 theoretical plates). The substance distribution was as follows:

In the case of the untreated cumene, the oxidation was terminated after 4 hours because of the uptake of oxygen had become insignificant, while the reaction mixture due to decomposition and or or side reactions had assumed a very dark color.

The oxidation of the cumene prepurified according to the invention proceeded quickly and smoothly with little Formation of unwanted by-products.

To demonstrate a better effect of the pre-cleaning with hydrogen fluoride, the following should be added An example of pre-cleaning with 96% sulfuric acid is given.

Brought in

ίο prelims

Cumene fraction

Follow-ups and backlog
loss

Gram

3788
312

2525

919

32

Weight percent

100

8.2
66.7
24.3

0.8

The cumene fraction had a refractive index of »» = 1.4910 and a boiling point of 153.2 ° 769 mm Hg. This fraction could only be oxidized to hydroperoxide with difficulty.

1 1 cumene fraction was 10 minutes at room temperature with 10 ecm 96% sulfuric acid in brought into contact with a separating funnel. A stream of air was blown through the liquids, to disperse the acid in the cumene. Then the mixture was allowed to settle, and the Sulfuric acid was withdrawn. The treatment was repeated five times, each time with a fresh one Amount of 10 ecm 96% sulfuric acid.

The cumene treated with acid was then successively mixed with 500 ecm of water and 500 ecm of 2N sodium hydroxide solution and washed again with water until the water remained neutral to litmus. After this Drying with calcium chloride, the acid-treated cumene was distilled.

The acid-treated and distilled cumene had a boiling point of 153.0 ° at 767 mm Hg and a refractive index of m | "= 1.4910. Das pretreated cumene was oxidized with an air stream of 50 liters per hour and kg of cumene at 110 °. It a rate of hydroperoxide formation of only 18 g per kilogram of cumene and Hour received.

If you compare the effectiveness of hydrogen fluoride with sulfuric acid, the same amount works Reagent getting the hydrogen fluoride faster.

Claims (1)

PATENT CLAIM: Process for the production of cumene hydroperoxide by oxidation of prepurified Cumene with oxygen or oxygen-containing gases in the liquid state, characterized in that one cumene with before the oxidation 0.1 to 10%, preferably about 5% by weight of hydrogen fluoride, based on the amount used Amount of cumene, treated. Considered publications:
German Patent No. 489 573;
British Patent No. 630,286;
Berkman, Morrel, Egloff, "Catalysis, Inorganic and Organic", 1940, pp. 934-939. 6Ϊ7 / 430 J. 57