DE1016689B - Process for the production of carbinols by catalytic hydrogenation of corresponding hydroperoxides - Google Patents

Description

GERMAN

It is already known that organic hydroperoxides can be reduced to the carbinols concerned and that ζ. Β. Phenyldimethylcarbinol produced when isopropylbenzene hydroperoxide is subjected to a reducing treatment. This reduction can be brought about by reducing agents such as sodium sulfite, sodium sulfide, ferrous sulfate or hydrogen iodide.

However, the reduction is more economical in terms of costs and the required reaction space with the help of hydrogen and a catalyst.

Although a number of hydrogen addition catalysts, such as. B. Nickel, platinum, copper, palladium, Silver, osmium or iridium, is known as the reaction between hydrogen and a Bringing hydrogen acceptor serving connection, however, some of these cannot in a satisfactory manner for the reduction of hydroperoxides to use because that Metal has a tendency to decompose the hydroperoxide into other products such as ketones or aldehydes, which contain fewer carbon atoms than the original hydroperoxides. For example occurs when isopropylbenzene hydroperoxide is treated with hydrogen in the presence a nickel catalyst, such as. B. Raneynickel, which is now often used for reduction reactions on organic Area of application, rapid decomposition of the hydroperoxide. Very little hydrogen is absorbed and the resultant is a mixture of the desired phenyldimethylcarbinol with Acetophenone and material that has a higher boiling point, while the nickel catalyst is ineffective is made so that it can no longer be used as an active hydrogen addition catalyst leaves. Similar reactions occur when using copper or copper chromite as catalysts on. It is also known that platinum is used as a catalyst in the reduction of hydroperoxides can be used with hydrogen. However, it has been found that side reactions can be significant occur and that if the hydroperoxide is not diluted with a water-soluble solvent the catalyst is often ineffective due to the coagulating effect of the water formed is made. In addition, the catalyst must be handled with care after use, because it tends to ignite spontaneously in air, causing organic matter to filter is used, e.g. B. paper or tissue, can catch fire. Furthermore, the catalyst can after repeated Use in such a finely divided state that it can only be used filter aids and leave long

for the production of carbinols
by catalytic hydrogenation
corresponding hydroperoxides

Applicant:

The Distillers Company Limited,
Edinburgh (Great Britain)

Representative: Dr. W. Schalk and Dipl.-Ing. P. Wirth,

Patent attorneys,
Frankfurt / M., Große Eschenheimer Str. 39

Claimed priority:
Great Britain 12 April 1955

Denis Cheselden Quin, Epsom, Surrey

(Great Britain),
has been named as the inventor

ten takes before it settles at the bottom of the reaction vessel, causing a separation is made more difficult by lifting. The same or similar difficulties occur with colloidal palladium or palladium black.

It was found that when using a spread on an activated alumina carrier or from this absorbed palladium in the production of carbinols by catalytic Hydrogen addition to hydroperoxides can avoid all of the disadvantages mentioned above.

Accordingly, the process according to the invention for the preparation of carbinols is characterized in that that you have an organic hydroperoxide with the same number of carbon atoms as the desired Carbinol under liquid conditions with hydrogen using on activated Palladium distributed in aluminum oxide acts as a catalyst.

The palladium catalyst distributed on activated alumina support or absorbed in it is known per se and can be produced in a known manner. For example, you can have activated Soak aluminum oxide with an aqueous solution of a palladium salt and the resulting mixture

709 699/412

mixed with a reduction process, ζ. Β. by treatment with formaldehyde or another reducing agent or by passing hydrogen over it.

The expression "under liquid conditions" is to be understood that the hydroperoxide is at least partially is in the liquid state, namely by working at a temperature above or on Melting point of the hydroperoxide in question is when the same at temperatures below 80 ° a solid substance, or by placing it wholly or partially in a at the temperature at which the Hydrogen treatment is to be carried out, liquid solvent inert to the hydroperoxide dissolves. Such a solvent may be used even under the reaction conditions be reducible; However, hydrogen deposition is allowed Do not prevent the hydroperoxide or poison the catalyst. As examples of such more suitable Solvents are water, alcohols, hydrocarbons and some ketones, esters or ethers, which can be used individually or in combination with one another.

Another possibility of treatment under the above-mentioned liquid conditions can be suspend or disperse the hydroperoxide in a liquid in which it is insoluble. For example one can use isopropylbenzene hydroperoxide, which is contained in acetophenone and phenyldimethylcarbinol Isopropylbenzene is dissolved, dispersing it in water, thereby reducing the problem of heat transfer the reaction is simplified.

It is preferable that the _pH value of a possible aqueous phase present from the start or formed during the reaction such. B. obtained by adding small amounts of sodium carbonate between 7 and 12, since the aluminum oxide carrier can suffer damage if it is exposed to acidic conditions for a long time.

The process according to the invention can therefore be carried out in a water-immiscible organic solvent be carried out because, as has been found, the water resulting from the reduction does not significantly detrimentally affect the effectiveness of the catalyst. Suitable, not with water Miscible solvents are e.g. B. Benzene and its homologues, paraffinic hydrocarbons such as those below mixtures known as petroleum ether. However, it is preferred to use the original solvent as the solvent To use compound from which the hydroperoxide is derived, and with particular Advantage is the solution that results from the autoxidation of the original compound. A part of original connection can e.g. B. be removed beforehand by evaporation before the mixture of is subjected to treatment with hydrogen according to the invention.

The hydrogen addition reaction can be carried out within a wide temperature range, being the preferred temperature with the one to use arriving hydroperoxide changes. It was found that the action of hydrogen already takes place at 0 ° and even below; higher temperatures, e.g. B. between 40 and 120 °, can, however, be used with great advantage, where- 6s by reacting with great rapidity. That is practical at these higher temperatures no by-products are formed and that the reaction involves the production of the carbinol in question is coming to an end while using other metal reduction catalysts further hydrogen addition at temperatures in the temperature range mentioned with formation of the respective hydrocarbon or decomposition to a ketone or aldehyde occurs easily, is surprising. In the case of aromatic hydroperoxides, the other metal reduction catalysts, hydrogen attachment to the aromatic nucleus takes place.

The amount of palladium to be used in and on the alumina support as well as the amount of The catalyst can fluctuate within wide limits. For example, 1 to 20 percent by weight, based on the amount of hydroperoxide to be subjected to hydrotreatment, good results timed when the palladized alumina catalyst contained 0.7% palladium.

After completion of the hydrogen treatment, the catalyst settles smoothly on the bottom of the reaction vessel. By inserting a fryed together Glass filter or a similar device, which is provided in a sump below the reaction vessel is, you can completely withdraw the liquid reaction mixture and separate it from the catalyst, without clogging the filter. The catalyst can then be reused by the reaction vessel is filled with fresh hydroperoxide-containing solution or suspension.

The filtered liquid contains the carbinol, solvent, if any, and the water produced in the reaction. The latter can be achieved by simple physical separation measures or remove by azeotropic distillation. If the amount is small, a dehydrating agent such as sodium sulfate or magnesium sulfate can be used. The catalyst can be used for the reduction of further amounts of the same or different Use connection again. But you can also use a suitable solvent, z. B. methyl alcohol or ethyl alcohol, wash out and save for later reuse.

The carbinol produced by the hydrogen treatment according to the invention can be extracted from the reaction mixture after it has been nitrated free of catalyst has been, in any suitable manner, e.g. B. by pouring off the water, by extraction with a suitable organic solvent or by distillation.

The inventive method can be applied to the hydroperoxides of aliphatic compounds, such as tertiary butyl hydroperoxide, or apply to those of aromatic compounds. In the latter case the hydroperoxides of a secondary nature, e.g. B. ethylbenzene hydroperoxide, or of a tertiary nature, such as isopropylbenzene hydroperoxide or p-cymene hydroperoxide. It can also be applied to the hydrogen treatment of dihydroperoxides, such as. B. meta- or para-diisopropylbenzene dihydroperoxide, apply, whereby the corresponding dicarbinols or carbinol hydroperoxides are formed. Finally can one thereby also secondary or tertiary hydroperoxides of aromatic compounds, which by Alkyl groups or substituted alkyl groups are substituted in the nucleus, reduce to carbinols. To the Example α, a-Dimethyl- (2-oxy-2-propyl) -benzyl hydroperoxide is reduced to bis- (2-oxy-2-propyl) -benzene.

The carbinols produced by the process according to the invention can be used for production of organic peroxides, in which two organic residues are linked by a peroxide group.

related to one another and having useful large-scale application as polymerization or vulcanization catalysts z. B. found in the manufacture of synthetic rubber.

It is known that a, ct-dialkylarylmethyl alcohols can be prepared by electrolytic reduction of a, a-dialkylarylmethylhydroperoxides. Compared to this process, the present process is cheaper since it does not require any expensive electrolytic devices and, due to the significantly shorter reaction time, no reaction vessels as large as in the known process are necessary.

It is also known, aromatic ketones and tertiary produce an aromatic radical containing alcohols by an a, a-Dialkylarylmethylhydroperoxyd with the reduced form of an electrical element that a standard oxidation-reduction potential has not less than about -1,0VoIt, is implemented. Compared to this process, too, for which large reaction vessels and large amounts of chemical reducing agents are required, the process according to the invention is cheaper and simpler.

The following examples serve to illustrate the practical implementation of the invention Procedure. The parts by weight given there are in the same proportion to the parts by volume as kilograms to liters.

example 1

The catalyst was prepared by adding 1 part of palladium chloride in 40 parts by volume of n / 10 hydrochloric acid Heating to 70 ° was dissolved. This solution was made into a suspension of 100 parts by weight chromatographic aluminum oxide poured into 200 parts by volume of water at 70 °. Then became 1 part by volume of a 40% strength aqueous formaldehyde solution was added to the mixture while stirring to reduce the palladium chloride. After a few minutes there was 50 parts by volume of a 5% sodium bicarbonate solution added with slow stirring and the mixture then left to stand for 30 minutes, while the temperature was kept continuously at 70 °. The catalyst was then used with two Amounts of water of 200 parts each, washed 4-5 pouring off, filtered and heated by heating for 2 hours dried to 100 °. The resulting product contained 0.7 weight percent palladium.

The reaction vessel for treatment with hydrogen consisted of a glass vessel that was at the bottom with was provided with a swamp. In this a pane of caked glass was attached, through which hydrogen is introduced in finely divided form or after switching on a vacuum line the mixture obtained from the reaction, freed from catalyst, can be filtered off with suction. The reaction vessel was with a stirrer, by means of which the catalyst can be kept in suspension, and a Provided a reflux condenser through which the excess hydrogen was drawn off.

100 parts by weight of crude isopropylbenzene hydroperoxide, obtained by oxidation of isopropylbenzene up to a conversion of 40% and then distilling off most of the unchanged Isopropylbenzene had been obtained and the final concentrate was about 83% isopropylbenzene hydroperoxide, some isopropylbenzene containing about 4% phenyldimethylcarbinol and 1% acetophenone filled into the reaction vessel with a little sodium carbonate solution as a stabilizer. 20 parts of how described above, prepared catalyst were moistened with isopropylbenzene hydroperoxide to a To avoid ignition of a hydrogen-air mixture in the reaction vessel, and introduced into the vessel. After washing out the space in the vessel and in the lines with hydrogen for the purpose of Removal of any air, the stirrer was started.

A brisk absorption of the hydrogen immediately began and the temperature rose. By attitude the rate of agitation could maintain the temperature at any desired level will. When maintained at 45 °, complete absorption was effected in 4 hours. By External cooling was able to reduce the hydrogen deposition even in 2/2 hours while maintaining the same level Temperature can be carried out in the reaction mixture. As soon as the hydrogen absorption stopped, the stirring was stopped. 50 parts of the reaction mixture including a large part the water produced that settled was on its way through the filter disk in the sump peeled off by applying negative pressure. These 50 parts were crude by an additional 50 parts by weight fresh isopropylbenzene hydroperoxide and the hydrotreatment continued.

In this way a total of 750 parts by weight of isopropylbenzene hydroperoxide were combined with hydrogen treated. The time it took to reduce the last 50 parts did not exceed that that was needed for the first 50 parts.

The phenyldimethylcarbinol that was obtained in the reduction was obtained in the pure state by after pouring off the water generated during the reaction, the reaction mixture was fractionally distilled. It represented about 86 percent by weight of the latter.

The excess hydrogen was returned to the reaction vessel on the way through the sump returned. The hydrogen consumed by the reaction was replaced with fresh gas.

If the same reaction using palladium-soaked chromatographic silica was carried out as a catalyst, the hydrogen addition took 10 hours to complete compared to the 2/2 hours with the alumina as a carrier, the amounts of palladium metal being the same in both cases.

Example 2

The reaction vessel described in Example 1 was filled with 50 parts by volume of crude hydroperoxide solution loaded by oxidizing m-diisopropylbenzene was obtained and about 50 percent by weight of monohydroperoxide, 4 parts by weight of dihydroperoxide, Contained 4% carbinol hydroperoxide, 15% monocarbinol and 17% m-diisopropylbenzene. It became 5 parts by weight of the catalyst prepared as described in Example 1 was added. The temperature the reaction mixture was kept at 75 to 80 ° and hydrogen was passed through, which was absorbed smoothly became.

The catalyst was allowed to settle and then separated from the liquid reaction product. He was then used for the hydrogen treatment of further batches of 50 parts by volume of m-diisopropylbenzene hydroperoxide solution used until a total of 1250 parts by weight of the crude solution had been treated with hydrogen in this way. One let

Claims (5)

In the course of the reaction the temperature dropped to about 55 °, then there was a tendency for the dicarbinol produced from the dihydroperoxide to crystallize out, which could lead to clogging of the sintered glass filter. This undesirable phenomenon could be avoided by working at a higher temperature, and a mixture of carbinols was obtained from which the mono- and dicarbinols were isolated by distillation. If the same reaction was carried out using a platinum oxide catalyst (PtO2), only about half the amount of hydrogen theoretically required for the production of the carbinol was absorbed, and no further hydrogen addition took place due to the coagulating effect of the water produced on the catalyst. This inhibitory action of the water on the catalyst could be achieved by homogenizing the liquid phase, e.g. B. by the addition of methyl alcohol can be avoided. Hydrogen addition was then continued, but it did not come to an abrupt end with the production of carbinol, since it began with the saturation of the benzene ring, which was also accompanied by the formation and further hydrogenation of considerable amounts of ketones from the hydroperoxide groups. Example 3 30 parts by weight of 1,3,3-trimethylindan-1-ylhydroperoxide (82% pure) were dissolved in 30 parts by volume of methyl alcohol and at room temperature and atmospheric pressure in the presence of 0.3 parts by weight of the palladium on aluminum oxide catalyst as described in Example 1 Shaken hydrogen. The temperature in the mixture rose somewhat in the course of the reaction. After 4 hours the absorption of hydrogen stopped. The catalyst was then filtered off and the solvent was removed by distillation under reduced pressure, leaving a residue of 26.7 parts by weight of crystalline 1,3,3-trimethylindan-1-ol. For comparison, a similar hydrogen treatment was carried out, except that a platinum oxide catalyst was used instead of the palladium-aluminum oxide catalyst. 10 parts by weight of 1,3,3-trimethylindan-1-yl hydroperoxide (98.5% pure) were dissolved in 30 parts by volume of methyl alcohol and treated with hydrogen in the presence of 0.05 parts by weight of platinum oxide under the same conditions as indicated above. After two and a half hours the absorption of hydrogen ceased. The resulting product did not want to crystallize, however, and the analysis showed that it consisted of a mixture in which trimethylindanol was only one of the constituents. To demonstrate the durability of the catalyst and its long-term effectiveness, the following example was carried out. Example 4 The catalyst of Example 1 was left to stand in the reaction vessel in the air for 18 days. After this time, 1500 parts by weight of crude isopropylbenzene hydroperoxide solution were introduced and treated with hydrogen at 35 ° to 55 °. The theoretical amount of hydrogen was absorbed within 30 hours. Upon examination of the resulting reaction mixture, it was found that it contained phenyldimethylcarbinol in an amount which exactly corresponded to the total amount of hydroperoxide as well as the amount of carbinol originally present in the batch. The original acetophenone content was unchanged. Another 3000 parts by weight of the crude isopropylbenzene hydroperoxide in amounts of 1000 parts by weight each were treated successively with the same catalyst with hydrogen. The time required for the final amount indicated that a decrease in catalytic efficiency had not occurred. Example 5 23 parts by weight of palladium-activated aluminum oxide catalyst, which had been prepared as described in Example 1, were added to a solution of 226 parts of secondary butylbenzene hydroperoxide in 858 parts of secondary butylbenzene, and the mixture was thermostatically added under 700 mm pressure with hydrogen at 24.6 ° regulated bath. The hydrogen absorption was rapid and suddenly stopped after 80 minutes. It was found that essentially all of the hydroperoxide had been converted to the corresponding carbinol without formation of acetophenone. Pa TEXT Λ N S I1 Π C C II E: 1. Process for the preparation of carbinols by catalytic hydrogenation Hydroperoxides with the same number of carbon atoms as the desired carbinol under liquid conditions with hydrogen, characterized in that as a catalyst activated alumina distributed palladium is used. 2. The method according to claim 1, characterized in that the hydroperoxide in one inert liquid medium, such as water, a water-miscible or immiscible solvent suspends or resolves. 3. The method according to claim 1, characterized in that the organic solvent the is the original connection from which the hy-, droperoxide was obtained by autoxidation. 4. The method according to claim 1 to 3, characterized in that the reaction at a Temperature between 40 and 120 ° performs. 5. The method according to claim 1 to 4, characterized in that the organic hydroperoxide Isopropylbenzene hydroperoxide is used. References considered: U.S. Patent Nos. 2,557,968, 2,543,763. © 70S 699/412 9.57