The uncondensed overhead product is removed from the top of accumulator 23 by means of a line 27, and it is then passed to a separating drum 29. 7. <> The first step in phenol production is oxidation of cumene to cumene-hydroperoxide (CHP) with 25-30% conversion. On the same hourly basis, this material contains 46 pounds of cumene and 34 pounds of water. At the temperatures employed generally for the separation, the steam employed is present in the separation zone as a vapor, hence, it is removed with the vaporous overhead product in the operation. In the stripping zone, the liquid material, e. g., containing at least 50% hydroperoxide, is contacted with additional quantities of steam in order to strip therefrom all or substantially all of the unreacted hydrocarbon. In order to obtain a high purity material containing hydroperoxide, a prohibitive quantity of stripping agent is necessary. While this technique is not as economical as using water which exists at an ambient temperature as the cooling medium, nevertheless, it is within the scope of the present invention. By this practice, it is to be noted that the quantity of steam which is present in the fractionation zone is enhanced by the quantity of steam which is added to the stripping zone for the purposes described above. In the separation of dialkylarylmethyl hydroperoxide from dialkylarylmethane by means of steam, it is necessary to employ a subatmospheric pressure when it is desired to produce a hydroperoxide product substantially free of water. MDL number MFCD00002129. The present invention is concerned with mixtures of hydroperoxide and unreacted hydrocarbon in WhlCh the hydroperoxide comprises about 10 to about 50% by weight of the total material. The cooled overhead product is passed from condenser 19 to a line 21, and thence, it flows to an accumulator 23. An object of this invention is to separate a dialkylarylmethyl hydroperoxide compound from a dialkylarylmethane compound. From a commercial standpoint, it is important to select the operating pressure of this separating zone so as to insure the subsequent condensation of steam and unreacted hydrocarbon at about the ambient temperature of Water, which can be used for indirect cooling of the overhead product from the separating zone. Cumene hydroperoxide technical grade, 80% Synonym: α,α-Dimethylbenzyl hydroperoxide CAS Number 80-15-9. 5. Further, the hydroperoxide is usually not stable at elevated temperatures, and so extreme care should be exercised in the selection of the conditions under which this material is recovered from the reaction product. On the same hourly basis, the remaining liquid product contains 9157 pounds of cumene and 100 pounds of cumene hydroperoxide.
Phenol and other related aromatic compounds can be prepared by the method involving the oxidation of a dialkylarylmethane type of compound in which a tertiary carbon atom is attached to the cyclic radical. Steam and liquid material from the stripping section B are combined and pass as a single stream into line 66 which leads to a heating element 68. Hence, on the basis of economics alone, such a technique is not desirable for commercial exploitation. In accordance with the present invention, a method for separating a dialklyarylmethyl hydroperoxide compound from a dialkylarylmethane compound is provided which comprises contacting a mixture of said compounds with steam in a subatmospheric separating zone under suitable conditions such that a substantial portion of the dialkylarylmethane compound is vaporized, and the remaining liquid contains a major amount of the dialkylarylmethyl hydroperoxide compound, and then the remain- 6o ing liquid is contacted with steam in a stripping zone in such quantities and under such conditions that substantially all of the dialkylarylmethane compound is removed therefrom, and a liquid containing substantially all of the dialkylarylmethyl hydroperoxide is produced. Conventional stripping is also not adequate for this purpose by reason that the product contains an undesired quantity of unreacted hydrocarbon and by-product materials. On the same hourly basis, this bottom liquid yield contains 2847 pounds of cumene hydroperoxide and 39 pounds of cumene. These by-product materials usually comprise not more than 2,706,708 Patented Apr. Hence, it is important from an operational standpoint to employ quantities of steam falling in the range mentioned above, otherwise, little or no benefit is derived from the use of the additional steam, or the operation is too expensive when considered from an economical standpoint alone. The decomposition of cumene hydroperoxide (CHP) was carried out in a batch reactor over supported solid acid catalysts, acid-activated montmorillonite K10 (Mont. 4. A process for separating dialkylarylmethane from dialkylarylmethyl hydroperoxide which comprises heating a mixture of said compounds containing about 10 to about 50% hydroperoxide to a temperature not greater than the decomposition temperature of said hydroperoxide, combining the heated mixture with steam in the amount of about 10 to 25%, passing the mixture in steam into a fractionation zone wherein the mixture is separated into an overhead vaporous fraction containing about 0.5 to about 5% of the hydroperoxide and the remainder is essentially all of the dialkylarylmethane which is fed to the fractionation zone and a liquid fraction containing about 55 to about 85% hydroperoxide and the remainder is essentially dialkylarylmethane, contacting the liquid fraction with additional steam in the amount of about 25 to about based on the feed to the fractionation zone in a stripping zone whereby the dialkylarylmethane is stripped from the hydroperoxide, passing a gaseous eflluent containing dialkylarylmethane from the stripping zone to the fractionation zone and yielding from the stripping zone a liquid fraction containing about 90 to about 95% of the hydroperoxide which is fed to the fractionation zone. The presence of byproduct materials tends to obscure the separation of the hydroperoxide from the unreacted hydrocarbon.
PASSING SAID MIXTURE AND STEAM INTO A SEPARATION ZONE WHEREIN THE MIXTURE IS SEPARATED INTO AN OVERHEAD VAPOROUS FRACTION CONTAINING SUBSTANTIALLY ALL DIALKYLARYLMETHANE AND A LIQUID FRACTION CONTAINING A MAJOR AMOUNT OF DIALKYLARLMETHYL HYDROPEROXIDE AND A MINOR AMOUNT OF DIALKYLARYLMETHANE, CONTACTING THE LIQUID FRACTIONS WITH ADDITIONAL STEAM IN A STRIPPING ZONE WHEREBY THE DIALKYLARYLMETHANE IS STRIPPING FROM THE DIALKYLARYLMETHYL HYDROPEROXIDE, PASSING THE STRIPPED DIALKYLARYLMETHANE MATERIAL FROM THE STRIPPED ZONE TO THE AFORESAID SEPARATION ZONE, AND YIELDING THE HYDROPEROXIDE SUBSTANTIALLY FREE OF DIALKYLARYLMETHANE FROM THE STRIPPING ZONE. In this mixture, on the same hourly basis, cumene comprises 9242 pounds and cumene hydroperoxide comprises 2947 pounds. US2706708A US390626A US39062653A US2706708A US 2706708 A US2706708 A US 2706708A US 390626 A US390626 A US 390626A US 39062653 A US39062653 A US 39062653A US 2706708 A US2706708 A US 2706708A Authority US United States Prior art keywords hydroperoxide steam dialkylarylmethane cumene zone Prior art date 1953-11-06 Legal status (The legal status is an … Hg absolute. Any liquid which is entrained in these vapors is discharged from the bottom of a separating drum by means of a line 31. Above the level of water (not shown) in accumulator 23, hydrocarbon is Withdrawn by means of a line 45, and it is transported by means of a pump 47 to a line 49. of mercury and at a temperature of F. By reason of the conditions existing in the fractionation section A, a vaporous overhead product is yielded from the top thereof by means of a line 17. %�쏢 For the purpose of maintaining steam in the separation zone in the uncondensed form, it is advisable to employ subatmospheric pressures in the range of about to about 200 mm. The liquid material being discharged from the bottom of fractionation section A enters stripping section B. Cumene hydroperoxide product is withdrawn from the bottom of stripping section B by means of a line 74 at the rate of 3266 pounds per hour. A process for separating dialkylarylmethane from dialkylarylmethyl hydroperoxide which comprises heating a mixture of said compounds containing about to about 50% of the hydroperoxide to a temperature not greater than the decomposition temperature of said hydroperoxide, combining the heated mixture with steam, passing the said mixture in steam into a fractionation zone wherein the mixture is separated into an overhead vaporous fraction containing about 0.5 to about 5% of hydroperoxide and the remainder is substantially all of the dialkylarylmethane which is fed to the fractionation zone and a liquid fraction containing about 55 to about 85% of the hydroperoxide and the remainder is essentially dialkylarylmethane, contacting the liquid fraction with additional steam in the stripping zone whereby the dialkylarylmethane is stripped from the dialkylarylmethyl hydroperoxide, passing a gaseous etfiuent containing dialkylarylmethane from thestripping zone to the fractionation zone, and yielding a liquid fraction from the stripping zone containing at least 90% hydroperoxide. of mercury. Linear Formula C 6 H 5 C(CH 3) 2 OOH . Cumene oxidation to cumene hydroperoxide Costa, C. a, Ribeiro, F. a, Lázaro, J. b a Instituto Superior Técnico b CEPSA Research Center Abstract This thesis of Master in Chemical Engineering is based on the study of cumene oxidation to CHP, the key reaction of a phenol production industrial process. 390,626. The dialkylarylmethane compound can be represented by the following structural formula: Rz Ar in which R1 and R2 represent alkyl groups and Ar represents aryl or alkaryl groups and H is hydrogen. By means of the additional quantity of steam which is fed to the stripping zone, the unreacted hydrocarbon is removed easily and efiectively from the liquid material, and it is thereby possible to produce a liquid product from the stripping zone which contains at least about 80% by weight of hydroperoxide or, more usually, at least by weight of hydroperoxide and up to about by weight thereof. It is typically used as an oxidizing agent. Products of decomposition of cumene hydroperoxide are methylstyrene, acetophenone, and cumyl alcohol. Specific examples of the unreacted hydrocarbon can be any one of the starting compounds from which the just enumerated hydroperoxides are derived. NACRES NA.22 For other homologues, a similar temperature difierential in the separation zone can be used, however, the actual values will differ, because the maximum permissible temperature varies with the specific material. Generally, the conditions of fractionation are selected on the basis of obtaining a liquid material containing at least about of the hydroperoxide which is introduced into the system, more usually, about to about of the hydroperoxide, on the same basis as a result of the initial contact of the feed with steam. The quantity of steam employed for this purpose varies from about to about by weight, based on the feed mixture. 5 0 obj
Phenol comes from cleavage of CHP, but in the … By means of a pump 35, the pressure is increased from 80 mm. 19, 1955 about 5% of the total mixture, and the remainder is unreacted hydrocarbon, and, generally, it comprises about 45 to about by weight.