DE1248020B - Process for the production of organic peroxide catalysts - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

BOIj

German KL: 12 g-U / 00

Number: 1248 020

File number: Sch 35154IV a / 12 g Filing date: May 13, 1964 Opened on: August 24, 1967

The invention relates to a process for the preparation of organic peroxide catalysts for the polymerization of unsaturated hydrocarbons by oxidation of hydrocarbons of the formula

¹ ar

in which R is an aliphatic hydrocarbon radical and Ar is an optionally alkyl-substituted aromatic or hydroaromatic hydrocarbon radical means with oxygen or oxygen-containing Gases and subsequent concentration of the oxidate solution.

It is known to include alkyl aromatic and alkyl cycloaliphatic hydrocarbons such as Isopropylbenzene, to be oxidized with oxygen-containing gases to the corresponding hydroperoxides. Included it is possible to add hydroperoxide concentrations of up to 75% if the oxidation time is sufficient reach. It has been recommended to use alkaline substances, e.g. B. aqueous alkali hydroxide, to add. On the other hand, however, it has also been stated that oxidation «5 expediently takes place without the addition of alkali, but the pH does not fall below 3 should be.

In the oxidation of terpene hydrocarbons, for example p-menthane, it is known that the reaction initially only to lead to a hydroperoxide concentration of about 5 to 10% and the obtained Hydroperoxide solution is then washed with an alkali solution and with water, after which if necessary renewed oxidation takes place. The aim of this process is to ensure that the oxidation of Terpene hydrocarbons, particularly high by-product formation is suppressed. For oxidation of the alkyl aromatic hydrocarbons mentioned at the beginning, this process seemed unsuitable, because already in a relatively short reaction time with or without the addition of alkali yields of relatively pure product are achievable.

It is also known to concentrate dilute hydroperoxide solutions of the aforementioned type by that they are treated in a thin film evaporator with a column attached.

As has been found, organic hydroperoxides obtained according to the aforementioned prior art, despite the good purity of the products, showed a considerable deficiency when they (especially in the form of more highly concentrated products) processes for the production of organic peroxide catalysts

Applicant:

Scholven-Chemie Aktiengesellschaft,

Gelsenkirchen-Buer, Dorstener Str. 227

Named as inventor:

Dr. Wilhelm Ester,

Dr. Wilhelm Heitmann, Herne

as catalysts, for example in polymerization reactions, were used. The diminished Activity could only be partially attributed to the fact that the hydroperoxides in small amounts carbinols contained as by-products of oxidation, which can interfere with the course of the polymerization. Apparently under the previously known reaction conditions arise special, not yet identified in detail Substances that show special activity-reducing properties when the hydroperoxides are used as catalysts can be used.

The invention is based on the surprising finding that organic peroxide catalysts for the polymerisation of unsaturated hydrocarbons which do not contain the substances that interfere with polymerisation can be produced by initially only carrying out the above-mentioned oxidation up to a hydroperoxide concentration between about 1 and less than 5%. , preferably about 3 to 4 ° / _0, performs, after which the Hydroperoxydkonzentration is increased in a known manner.

After the oxidation stage, an alkali wash, optionally a water wash, can be switched on. The oxidate can also go into an oxidation stage immediately after the oxidation, in which it, for example, in accordance with German patent specification 1,082,254 in a thin-film evaporator conventional design with attached distillation column is brought to a higher concentration.

The method, one goes in detail before so that the oxidized AusgangskohlenwasserstofT at temperatures between about 80 and 15O ⁰ C with oxygen or an oxygen-containing gas such as air. You can work under normal pressure or slightly elevated pressures up to about 10 atm. The so

709 638/522

3 4

recovered, for example 4% hydroperoxide solution. .

can then with diluted, aqueous or aiko example ·!

holischen, about 1 B2W to 50 ° / ₀ by weight solutions. As in German patent specification 1082 255

Suspensions of alkaline substances, in particular described, are p-menthane in such an amount

the carbonates or hydroxides of the alkali or 5 are pumped continuously into the oxidation reactor

Alkaline earth metals, briefly mixed intimately. and the corresponding amount of oxidized solution

It is advisable to remove a centrifugal pump so that the hydroperoxide concentration in the

use the hydroperoxide solution in the turbo-reactor at the given operating conditions

lenter flow is mixed with the alkali. It stays at a constant level. This is how the p-menthane became

in this case it is sufficient to require a reaction period, io at a temperature in the reactor of 12O ⁰ C, a

which are less than 5 seconds, preferably between a pressure of 2.8 atmospheres, an O ₂ content in the end gas

0.2 and 0.8 seconds. A ratio of 1.8% and a p-menthane / hydroperoxide content is also possible

Mixture by means of another suitable stirring device - oxidized in the reactor by 3.0, 4.5, 7.0 or 10.0%,

services such as blade stirrers; however, the oxidation product withdrawn from the reactor is longer

Residence times of several minutes, e.g. B. 15 minutes 15 was with dilute soda solution and with water

ten, complied with. The mixture is then washed and then distilled in a thin

Separator fed, in which it is in an aqueous film evaporator to a content of at least

and separates an organic phase. The top layer, 50% p-menthane hydroperoxide concentrated on. Included

the hydroperoxide dissolved in hydrocarbon showed that with the same dimensions of the

contains, but still occurs as an emulsion on 20 thin-film drying vessels and one corresponding to the

and cannot be processed easily. Treating lower concentration greater exposure in the

if you delt this product with a suitable washing ratio 37: 22: 15: 10 the content of p-menthane

medium, such as water or mono- or polyvalent hydroperoxide in the sump vent 79.5% or 80.8%

Alcohols such as methanol or glycol, in one or 73.1% or 64.6%,

second pump with separator, one obtains a 25 These p-menthane hydroperoxide concentrates

very quick and clear separation of the layers by adding the appropriate amount

with a very pure Hydroper- p menthane as the upper layer with a peroxide content of 54%

oxide solution accumulates. The bottom layer that is still thin.

considerable amounts of hydroperoxide and carbon- The activity of these peroxide samples in emul-

Contains hydrogen, then the first alkaline 30 sion polymerization of butadiene-styrene at +5 ⁰ C.

Washing process- re-fed so that losses are in a by H. Leverne Williams in

be avoided completely. Here the C.E. S c hildknecht, Polymer Processes, p.156ff.,

Appropriate feed investigated in the centrifugal pump before described system. As polymer

the first separator, as this results in a dilution approach that is described in the rubber manual,

of the supplied alkali in apparatus ₃₅ Vol. I, p. 357, for the recipe given for SBR1500

is made and the detergent is used at the same time. The ones with the p-menthane hydroperoxide,

is used again in the dilution process. which was oxidized to 7.5% peroxide in the reactor,

The amount of oxidate obtained after 14 hours of polymerization can also be obtained without intermediate treatment

be passed directly to the concentration stage. the activity of rubber is set equal to 100.

The process is expediently carried out continuously. All other activities are based on this value

borrowed. The procedure here is as follows: and have been compiled in Table 1.

Oxidation vessel continuously with the same amount “....

fed to output hydrocarbon such as ^ae to per-

oxide solution is withdrawn. This then goes to Pero * ydspiegel

a centrifugal pump in which they operate with alkali or alkali 45 j _m reactor

carbonate solution is mixed. Then comes the «/ _o
Mixture to the first separator, its upper layer

continuously deducted and in the following 3 q

The pump is washed with the detergent, select 4 * 5

rend the lower layer of the first separator partly- 50 Jq

wisely remains in circulation. A partial flow is constantly '

activity

103.3
100.0

79 7

peeled off and replaced with fresh alkali solution. "" '"'

The withdrawn aqueous or alkaline solutions The comparison clearly shows the superiority

By means of filtration and ion exchangers, concentrates that are reduced to less than 5% in the

nigt and fed back into the washing process. 55 oxidation stage were oxidized.

The lower layer of the second separator goes. .

then back to the first separator. Example 2 thus obtained

Hydroperoxide solution undergoes another oxidation. A mixture of p- and m-diisopropylbenzene

fed in and subjected to a washing process, or is as in Example 1 at 120 ⁰ C continuously

it can be worked up in the usual way, 6o oxidized. The peroxide level in the reactor is

for example by vacuum distillation, given 2.8, 3.9, 7.6, 21.1 and 30.1%, respectively. The cleaning and

if using film evaporators. Concentration takes place as in Example 1. The

The method is particularly suitable for investigating the products in the bottle polymer

Position of use as free radical catalysts as in Example 1, showed here too that the

suitable hydroperoxides, in particular cumene hydro- 65 samples that point to low peroxide contents below 5%

peroxide, diisopropyl monohydroperoxide, p-menthane had been oxidized, a considerably higher rate

hydroperoxide, pinan hydroperoxide and other han activity and thus the greatest space-time

the usual hydroperoxides of the type mentioned. Yield.

5
Table 2

Peroxide level activity in the reactor 116.8 2.8 113.4 3.9 104.7 7.6 94.5 21.1 81.7 30.1

Example 2 clearly shows that for the strong The decrease in activity with oxidation to a higher peroxide concentration is evidently not the same as in the main cause of the oxidation by-products that occur. It can be assumed, that at higher peroxide concentrations substances of a kind not yet identified in detail occur, the exert a specific influence on the course of the polymerization. The emergence of these substances

ίο is due to low peroxide concentrations in the Avoided oxidation.

Example 3

That obtained in example 2 during the oxidation with a hydroperoxide content in the reactor of 2.8% Concentrate (I) is made with synthetically produced p-isopropyl-aceto-phenone (II) and with p-isopropylphenylene-dimethylcarbinol (III) mixed. These products are typical by-products of the oxidation stage. The activity of different mixtures with these products is shown in the table below.

Table 3

50% I + 50% diisopropylbenzene

50% I + 10% II + 40% diisopropylbenzene

50% I + 10% III + 40% diisopropylbenzene

50% I + 10% + 10% ΠΙ + 30% diisopropylbenzene

Activity * 5

116.8 111.4 110.5 107.6

If one compares the activity values determined above, which only decrease slightly, with those of the

Claims (1)

Claim: Process for the preparation of organic peroxide catalysts for the polymerization of unsaturated ones Hydrocarbons by oxidation of hydrocarbons of the formula Rx / Ά R ' Ar in which R is an aliphatic hydrocarbon radical and Ar is an optionally alkyl-substituted one aromatic or hydroaromatic hydrocarbon radical means with oxygen or oxygen-containing gases and subsequent concentration the oxidate solution, characterized in that the oxidation is carried out first only up to a hydroperoxide concentration between about 1 and less than 5%, preferably about 3 to 4%> carries out, after which the hydroperoxide concentration is known per se Way is increased. Considered publications:
German patent specifications No. 1082 255, 1082 254 709 638/522 8.67 © Bundesdtuckerei Berlin