SE182995C1

SE182995C1 -

Info

Publication number: SE182995C1
Authority: SE
Publication date: 1963-01-01

Description

Uppfinnare: H Sodomann, B Hauschulz och A Deka Prioritet begiird iron den 15 jail 1959 (Forbundsrepubliken T gskland) Vid fenolsyntes genom syraspaltning av isopropylbensenhydroperoxid erhaller man en spaltblandning, som forutom fenol och ace-ton innehaller en rad andra produkter, sásom a-metylstyren, dimetylfenylkarbinol och acetofenon samt aven stora mangder av vid oxidationen icke omsatt isopropylbensen. Forutom dessa produkter erhaller man ¥ en aterstod, som har hogre kokpunkt an fenol och acetofenon och som forutom tjarartade produkter innehaller en stor mangd p-kumylfenol. Vid upparbetning av spaltblandningen till ren fenol bereder avskiljningen av denna aterstod stora svarigheter. Det ãr i synnerhet svart att avskilja aterstoden pa sadant soft, all den endast innehaller en ringa miingd fenol och andra produkter, vilka kunna tagas tillvara Mom ramen for hela processen. Inventors: H Sodomann, B Hauschulz and A Deka Priority begiird iron 15 Jail 1959 (Federal Republic of Germany) Phenol synthesis by acid cleavage of isopropylbenzene hydroperoxide gives a cleavage mixture which, in addition to phenol and acetone, contains a number of other products, such as α-methylstyrene , dimethylphenylcarbinol and acetophenone as well as large amounts of isopropylbenzene not reacted in the oxidation. In addition to these products, a residue is obtained which has a higher boiling point than phenol and acetophenone and which, in addition to tar-like products, contains a large amount of p-cumylphenol. When working up the column mixture to pure phenol, the separation of this residue prepares large equivalents. It is especially difficult to separate the residue in such a soft way, all of which contain only a small amount of phenol and other products, which can be used as part of the whole process.

For att overvinna de angivna svarigheterna har man f5reslagit att upphetta den efter avskiljningen av fenolen erhallna, av mer hogkokande bestandsdelar an fenol bestaende aterstoden till en temperatur av 200-400° C och att infora de darvid erhallna produkterna, vilka i huvdsak utgoras av metylstyren, fenol och acetofenon forutom mer hogkokande produkter i en efteral kopplad destillationskolonn, i vilken man utfor en separering av de lagkokande bestandsdelarna, med vilka forstas metylstyren, fenol och acetofenon, fran de hogre kokande bestandsdelarna. Dessa lagkokande bestandsdelar separeras i annu en kolonn pa sadant satt, att fenol och metylstyren uttagas upptill och fenol och acetofenon kvarstanna sasom destillationsaterstod. Den sfilunda erhallna aterstoden av acetofenon och fenol bildar en azeotrop blandning. Denna blandning mdste for sig bearbetas, till fenol, for vilket andamal forhallandevis omstandliga arbetsmetoder och -forlopp erfordras. De upptill i sistna.mnda kolonn uttagna produkterna ledas till fenolupparbetning, varvid man fore den egentliga renutvinningen av fenolen forst maste avdraga a-metylstyren upptill ur en forsta kolonn. In order to overcome the stated responsibilities, it has been proposed to heat the residue obtained after the separation of the phenol, consisting of higher boiling components of phenol to a temperature of 200-400 ° C and to introduce the products thus obtained, which consist mainly of methylstyrene. phenol and acetophenone in addition to more high-boiling products in a post-coupled distillation column, in which a separation of the low-boiling constituents, with which methylstyrene, phenol and acetophenone, are separated from the higher-boiling constituents is carried out. These low boiling components are separated in another column in such a way that phenol and methylstyrene are removed at the top and phenol and acetophenone remain as distillation residue. The resulting residue of acetophenone and phenol forms an azeotropic mixture. This mixture must be processed separately, into phenol, for which purpose relatively cumbersome working methods and processes are required. The products taken from the top of the last-mentioned column are led to phenol work-up, in which case the actual pure recovery of the phenol must first be stripped of α-methylstyrene at the top from a first column.

Vid delta forfarande intrader redan kort efter krackningen av aterstoden av metylstyren och karbinol en avsevard aterbildning till kumylfenol, sá att krackningseffekten till en icke o-vasentlig del 'Ater kompenseras. Dessutom belastas denna fenolkolonn genom att de lagkokande amnena foras till fenolkolonnen. Vidare uppkommer genom anvandningen av krackning och de Mda efterkopplade separeringskolonnerna fiir de lagkokande amnena och separeringen av dessa lagkokande amnen i metylstyren, fenol och acetofenon eft vasentligt extra behov av energi. Detta kanda forfarande hanfor sig till avskiljning av fenolen enligt det sa kallade torra forfarandet. In the delta process, already shortly after the cracking of the residue of methylstyrene and carbinol, a considerable regeneration into cumylphenol occurs, so that the cracking effect is compensated to a not insignificant part. In addition, this phenolic column is loaded by passing the low-boiling substances to the phenolic column. Furthermore, through the use of cracking and the Mda post-coupled separation columns for the low-boiling substances and the separation of these low-boiling substances into methylstyrene, phenol and acetophenone, there is a substantial additional need for energy. This can be a procedure for separating the phenol according to the so-called dry process.

Det har nu visat sig, att man vid arbete enligt det sO. kallade Alta forfarandet, vid vilket kolvatena avdestilleras azeotropt fran fenol i narvaro av vatten, pa ett vasentligt enklare salt och med en vasentligt Mitre nyttig effekt kan genomfora hela renframstallningen av fenolen och utnyttjandet av de i aterstoderna amm kvarvarande produkterna, sasom fenol, karbinol och pa motsvarande sat metylstyren, varvid icke nagot extra behov av energi uppkommer och enerigbehovet per en-het utvunnen fenol till och med blir lagre. It has now been shown that when working according to the sO. called the Alta process, in which the hydrocarbons are azeotroped from phenol in the presence of water, on a substantially simpler salt and with a substantially miter beneficial effect can carry out the entire purification of the phenol and the use of the residues in the residues, such as phenol, carbinol and pa correspondingly sat methylstyrene, whereby no additional need for energy arises and the energy requirement per unit of recovered phenol even becomes lower.

Foreliggande uppfinning avser ett forfarande for utvinning av ren fenol fran syraspaltning av isopropylbensenhydroperoxid, varvid man efter eliminering av syrakatalysatorn och a-vdestillering av acetonen avskiljer de i blandningen ingaende kolvatena genom azeotrop destillation i narvaro av vatten frail fenol och de mer hogkokande komponenterna och avskiljer fenolen sjalv i en efterkopplad kolonn fran en till overvagande del av acetofenon, dimetylfenylkarbinol saval som kurnylfenol och andra polymerisations- och kon- 2— — densationsprodukter bestaende aterstod och i en eller flera efterkopplade destillationskolonner bearbetar denna fenol till ren fenol, medan den i rafenolkolonnen erhallna aterstoden krackas genom temperaturbehandling. Det utmarkande for forfarandet är att krackningen genomfores i bottenrummet (sumpen) i en kolonn eller i ett lampligt karl under aterflode av vattenfasen fran kolvatekolonnen och att angorna fran krackningsanordningen utan kondensation inledas i en efterkopplad destillationskolonn och i denna kolonn, likaledes under aterflode av vattenfasen i kolvatekolonnen destilleras pa sadant salt, att acetofenonen kvarstannar i bottenrummet i denna kolonn, medan de lagkokande krackningsprodukterna innehallande angorna utan kondensation aterforas till kolvatekolonnen. The present invention relates to a process for recovering pure phenol from acid cleavage of isopropylbenzene hydroperoxide, wherein after elimination of the acid catalyst and α-distillation of the acetone, the hydrocarbonaceous components are separated by azeotropic distillation in the presence of water from phenol and the higher boiling phenols. itself in a post-coupled column from a predominantly acetophenone, dimethylphenylcarbinol saval such as kurnylphenol and other polymerization and condensation products existing residue and in one or more post-coupled distillation columns this phenol processes to pure phenol, while in the rafenol column it is cracked by temperature treatment. The distinguishing feature of the process is that the cracking is carried out in the bottom space (sump) in a column or in a lamp vessel under reflux of the aqueous phase from the flask column and that the vapors from the cracking device without condensation are initiated in a subsequent distillation column and in this column, also under reflux water. The hydrocarbon column is distilled on such a salt that the acetophenone remains in the bottom of this column, while the boiling boiling cracking products containing the vapors are returned to the hydrocarbon column without condensation.

Enligt detta forfarande arbetar man foljaktligen efter avskiljningen av acetonen i den darefter foljande kolvatekolonnen pa sadant satt, att kolvatena, dvs. isopropylbensen och styren, avdestilleras med vatten i form av en pseudoazeotrop. I bottenrummet till denna kolonn installas tva laser, av vilka den ena utg6r en vattenfas, som innehaller en ringa mangd fenol och den andra omfattar den sâ kallade organiska fasen, vilken innehaller huvudmangden 'av fenolen och hela mangden aterstod. Den organiska fasen i denna kolvatekolonn kan dessutom foras till en efterkopplad kolonn, i vilken en separering av de organiska substanserna fran vatten genomfores. Accordingly, according to this procedure, after the separation of the acetone, the subsequent hydrocarbon column is operated in such a way that the hydrocarbons, i.e. isopropylbenzene and styrene, distilled off with water in the form of a pseudoazeotrope. In the bottom space of this column are installed two lasers, one of which constitutes an aqueous phase, which contains a small amount of phenol and the other comprises the so-called organic phase, which contains the main amount of the phenol and the entire amount of residue. In addition, the organic phase in this hydrocarbon column can be fed to a post-coupled column, in which a separation of the organic substances from water is carried out.

Den organiska fasen fOres till en sd kallad rafenolkolonn, i vilken huvudnaangden fenol avdrages vid toppen av kolonnen. Den darvid erhallna aterstoden innehaller exempelvis fortfarande 15-25 % fella', 15-% acetofenon och ungefar 12-18 % karbinol, 1525 % kumylfenol och ungefar 30 % arartade substanser. For utvinning av den fenol, som ingar i denna aterstod, Wes aterstoden till ett krackningskfirl, van temperaturen halles inom ett interval' av ungefir 220-350° C och foretradesvis 270-290° C, varvid framfor alit den i aterstoden ingaende kumylfenolen spaltas och karbinolen dehydratiseras. Man kan arbeta vid normalt tryck, undertryck eller overtryck. The organic phase is fed to a so-called rafenol column, in which the main amount of phenol is removed at the top of the column. The residue thus obtained still contains, for example, 15-25% fella ', 15-% acetophenone and about 12-18% carbinol, 1525% cumylphenol and about 30% similar substances. To recover the phenol contained in this residue, the residue is formed into a cracking vessel, the temperature being maintained in a range of about 220-350 ° C and preferably 270-290 ° C, the cumylphenol present in the residue being decomposed and the carbinol is dehydrated. You can work at normal pressure, negative pressure or overpressure.

For att genomfora spaltningen av de i Aterstoden inghende nyttiga substanserna erfordras f8r det fOrsta att en lamplig temperatur foreligger i bottenrummet 1 detta karl och for det andra ar det lampligt att toppen av denna krackanlaggning uppvisar en aterflodesanordning, som gor det mojligt att halla temperaturen vid toppen sá lag som mojligt. Lampligen fares dad& vattenfasen fran kolvatekolonnen sasom aterflode. Vid detta arbetssatt an det mojligt att spalta praktiskt taget alla s8nderdelbara substanser, t. ex. dimetylfenylkarbinol och kumylfenol. For detta andamal Or det lampligt att vid toppen halls en temperatur av upp till ungefar 170° C. Vid hogre temperatur, t. ex. vid 200° C, kan en del av dimetylfenylkarbinolen och aven kumylfenolen i osonderdelat tillstand destillera Over toppen av kolonnen. Detta har emellertid ingen skadlig inverkan, om man, sasom beskrives ytterligare i det f8ljande, tillser att temperaturen vid toppen av den efterfoljande kolonnen installes sa, att ingen acetofenon avgar Over toppen. In order to carry out the decomposition of the useful substances contained in Aterstoden, it is required, firstly, that an appropriate temperature is present in the bottom chamber of this vessel and, secondly, that the top of this cracking plant has a backflow device which makes it possible to maintain the temperature at the top. as law as possible. Lampligen fares dad & water phase from the piston column as aterflode. With this approach, it is possible to decompose practically all decomposable substances, e.g. dimethylphenylcarbinol and cumylphenol. For this purpose, it is appropriate to maintain a temperature of up to about 170 ° C at the top. At higher temperatures, e.g. at 200 ° C, a portion of the dimethylphenylcarbinol and even the cumylphenol in the undivided state can distill over the top of the column. However, this has no detrimental effect if, as further described below, care is taken to ensure that the temperature at the top of the subsequent column is installed so that no acetophenone emits over the top.

Det liar dessutom visat sig, att det till fOljd av vattenaterflodet frail kolvatekolonnen icke sker flagon aterbildning, exempelvis av kumylfenol utan metylstyren och fenol. Orsaken hartill är att Oka i det forhallandet, att en kraftig utspadning av dessa reaktionsbenfigna produkter sker genom vattenaterf16- det och att dessutom dessa reaktionsbenagna produkter hallas vid en forhallandevis lag temperatur. De fran krackningskarlet erhallna angorna, vilka i huvudsak innehalla vat-ten, fenol, metylstyren, acetofenon och en ringa mangd kolvaten, ledes utan mellanliggande kondensation till en efterkopplad koloam. Energibehovet i krackningskarlet tillgodogores genom denna atgard fullstandigt i den efterkopplade kolonnen utan forluster. Den efterkopplade kolonnen arbetar pa sa salt, att den likaledes sasom aterflode innehailer vattenfasen Fran kolvatekolonnen. Temperaturen vid toppen av denna kolonn halles vid ett sadant gradtal, att acetofenon lake overdestillerar. It has also been found that due to the water ether flow from the hydrocarbon column there is no flake formation, for example of cumylphenol without methylstyrene and phenol. The reason for this is to increase the ratio, that a strong dilution of these reactive products takes place through the water heritage16 and that in addition these reaction-prone products are kept at a relatively low temperature. The vapors obtained from the cracking vessel, which mainly contain water, phenol, methylstyrene, acetophenone and a small amount of the hydrocarbons, are passed without intermediate condensation to a post-coupled column. The energy requirement in the cracking vessel is met by this action completely in the connected column without losses. The downstream column operates on such a salt that it also contains the water phase from the piston column as a backwater. The temperature at the top of this column is kept at such a degree that acetophenone lake over-distills.

Vid de fOretradesvis valda arbetstemperaturerna i krackningskarlet erhalles en 'Aterstod, som an pumpbar vid en temperatur Over 100° C. Om temperaturen i kraekningskarlet vasentligt overstiger 300° C, intrader en hoggradig forkolning, som nodvandiggar lopande rengoring av anlaggningen. Den i krackningskarlet fortfarande pumpbara aterstoden, som varken innehaller fenol eller andra produkter, vilka kunna tillgodogoras mom ramen for fenolprocessen, pumpas till bottenrummet i den efterkopplade kolonnen. Genom denna atgard tillgodogor man sig aven den del av energien, som ingar i denna aterstod, i den efterfoljande kolonnen. At the preferably selected operating temperatures in the cracking vessel, a residue is obtained, which can be pumped at a temperature above 100 ° C. If the temperature in the cracking vessel substantially exceeds 300 ° C, a high degree of charring occurs, which necessitates continuous cleaning of the plant. The residue still pumpable in the cracking vessel, which does not contain phenol or other products which can be used as part of the phenol process, is pumped to the bottom space in the downstream column. Through this action one also assimilates the part of the energy which is contained in this residue, in the following column.

Fran denna efterkopplade kolonn avdrages hela aterstoden. Den innehaller hela mangden acetofenon och fortfarande en endast ringa mangd fenol; genom spaltning utnyttjningsbara substanser inga icke langre i denna aterstod. Genom att acetofenonen finnes kvar i aterstoden an denna latt att hantera, enar den Or flytande 5.ven vid rumstemperatur. lake heller i denna kolonn, som Or kopplad after krackningsanlaggningen, kan nagon aterbildning av exempelvis metylstyren och fenol till kumylfenol uppkomma, mar kolonnen arbetar vid en mycket lag temperatur och vattenhalten kraftigt Overvager 1 jamforelse med de reaktionsbenagna substanserna. For anvandning av den i denna kolonn erforderliga energien inledes den vid toppen erhall- — —3 na produkten i ingform, dvs. utan mellanliggande kondensation, i kolvatekolonnen. Genom denna atgard uppnar man att i denna kolonn hela den energimangd, som anvants i krackningskarlet resp. i den efterkopplade kolonnen, fullstandigt utnyttjas i kolvatekolonnen, varfor faljaktligen det inkopplade krackningskarlet och den efterkopplade separeringskolonnen kan drivas praktiskt taget utan ytterligare energibehov, raknat pa hela destillationen. linnu en fordel med detta arbetssatt ãr att de vid krackningen bildade kolvatena kunna films till det stalle i anlaggningen, i vilket de utvinnas over toppen av en kolonn och kunna fans till vidarebearbetning. Genom aterfthingen av angorna till kolvatekolonnen belastas fenoldelen av anlaggningen icke pa nagot satt ytterligare och därfor kan icke heller sasom eljest ar fallet nâgon aterbildning till kumylfenol ske vid denna del av destillationen. Man erhaller darigenom kvalitativt sett en mycket hogvardig produkt. Utbytet av fenol av farmakopekvalitet kan i forhallande till vad som är fallet vid det kanda forfarandet genom ovan beskrivna at-girder stegras med omkring 3-5 %. Dessutom sjunker energibehovet per enhet fenol med omkring 3-%. From this connected column the entire residue is deducted. It contains the whole amount of acetophenone and still only a small amount of phenol; substances which can be utilized by cleavage are no longer present in this residue. Because the acetophenone remains in the residue and is easy to handle, it also forms a liquid 5. even at room temperature. lake also in this column, which Or coupled after the cracking plant, some conversion of, for example, methylstyrene and phenol to cumylphenol may occur, but the column operates at a very low temperature and the water content strongly. For use of the energy required in this column, the product obtained at the top is initiated in ing-form, i.e. without intermediate condensation, in the flask column. Through this procedure it is achieved that in this column the entire amount of energy used in the cracking vessel resp. in the post-coupled column, is fully utilized in the flask column, so that the connected cracking vessel and the post-coupled separation column can be operated practically without additional energy requirements, drawn on the entire distillation. Another advantage of this method is that the pistons formed during the cracking can be filmed to the stable in the plant, in which they are extracted over the top of a column and can be processed for further processing. Due to the return of the vapors to the hydrocarbon column, the phenol part of the plant is not loaded in any further way and therefore, as is not the case otherwise, no conversion to cumylphenol can take place in this part of the distillation. In this way, a very high-quality product is obtained qualitatively. The yield of pharmacopoeia-grade phenol can be increased by about 3-5% relative to what is the case in the known process by the above-described procedures. In addition, the energy requirement per unit of phenol decreases by about 3%.

Med det »vata» fOrfarandet forstar man ett arbetssatt, vid vilket man med fordel utnyttjar det farhallandet, att kolvatena, t. ex. kumen och metylstyren, bilda en lagkokande pseudoazeotrop med vatten. Salunda Egger exempelvis kokpunkten for ren kumen under normalt tryck vid 152° C, medan pseudoazeotropen vatten—kumen under samma betingelser kokar vid 98° C. By the "wet" process is meant a mode of operation in which the advantage is that the hydrocarbons, e.g. cumin and methylstyrene, form a low-boiling pseudoazeotrope with water. Salunda Egger, for example, the boiling point of pure cumin under normal pressure at 152 ° C, while the pseudoazeotropic water-cumin under the same conditions boils at 98 ° C

Farfarandet beskrives narmare 1 det följande medelst en sasom exempel angiven, fran driftssynpunkt sarskilt fordelaktig utforingsform under hanvisning till bifogade ritning. Den fran syraspaltningen av isopropylbenzenhydroperoxid erhallna blandningen, som forst befriats frail dari inghende syrakatalysator och aceton, fares genom en ledning 2 till en. kolonn 1, i vilken den befrias frail bestandsdelar, vilka koka vid lagre ternperatur an fenol, dvs.. sarskilt isopropylbensen och a-metylstyren (ledning 3). I denna kolonn arbetar man lampligen genom vattenangdestillation. I bottenrummet erhaller man darvid en vattenfas, som innehaller en ringa mangd fenol och en organisk fas, som innehaller huvudmangden fenol farutom hagkokande aterstoder och nagot vatten. Den organiska fasen avdrages och fores genom en ledning 5 till toppen av en efterkopplad kolonn 6, medan vattenfasen f8res genom ledningar 7 och 9 till toppen av kolonnen 6, varvid en delstrom fores genom ledningar 8 och 13 till toppen av en blasa 14 resp. genom ledningar 8 och 10 till toppen av en kolonn 11. Det fran toppen av kolonnen 6 avdragna vattnet fares i angform genom en ledning 12 till kolonnen 1. Restfladet frail kolonnen 6 bestar efter avdrivningen av vattnet i huvudsak av fenol med hogkokande aterstod. Detta restflade avdrages och fares genom en ledning 15 till en kolonn 16, i vilken fenolen avdestilleras fran aterstoden och sedan genom en ledning 4 fares till annu en kolonn (icke visad pa. ritningen), dar den. upparbetas till ren fenol. Aterstoden, som innehaller polymerisations- och kondensationsprodukter med hogre kokpunkt, bland annat kumylfenol och dessutom dimetylfenylkarbinol saval som fenol i en mangd av exempelvis 27 %, fares genom en ledning 17 till bottenrummet i bla.san 14, som Mlles vid en. temperatur av 220-350° C, foretradesvis 270-290° G. Man maste darvid draga forsorg om att den i toppen av blasan 14 radande temperaturen av ungefar 170° G icke Overskrides for att undvika, att vasentliga mangder karbinol averdestillera. Denna omvandlas vid den forhojda temperaturen i blasan under vattenavspaltning till a-metylstyren, som sedan vid det fortsatta forloppet av forfarandet utvinnes sasom destillat frail kolonnen 1 och efter hydrering till kumen omedelbart kan anvandas vid oxidationssteget. Fran toppen av blasan 14 avdrager man I angform en blandning, som huvudsakligen bestar av styren, acetofenon, fenol och vattenanga och som utan flagon mellanliggande kondensation fares genom en ledning 18 till den undre delen av kolonnen 11. Den val pumpbara bottenrumsprodukten fran blasan 14, som framf Or allt innehaller tjarartade bestandsdelar forutom endast 0-1 % fenol, fares genom en ledning 19 till bottnen av kolonnen 11. Darifran avdrages genom en ledning 20 en upp till ungefor 8 % fenol innehallande tjarartad aterstod, i vilken aven hela acetofenonmangden (ungefar 25 %) ingar. Den vid toppen av kolonnen 11 uppratthallna temperaturen ligger mellan ungefar 90 och 130° C, medan bottenrummets temperatur ligger mellan ungefar 200 och 215° C. Pa detta Mkt forhindrar man att acetofenon fortfarande ingar i den dar avdragna angstrom-men. Den angformiga produkten fores sedan utan mellanliggande kondensation genom en ledning 21 till den undre delen av kolonnen 1. The process is described in more detail in the following by means of an example specified, particularly advantageous from an operational point of view, with reference to the accompanying drawing. The mixture obtained from the acid cleavage of isopropylbenzene hydroperoxide, which has first been liberated from the acid catalyst and acetone, is passed through line 2 to one. column 1, in which it is liberated from constituents which boil at a lower temperature than phenol, i.e. isopropylbenzene and α-methylstyrene in particular (line 3). In this column, one works aptly through water distillation. In the bottom room, an aqueous phase is obtained, which contains a small amount of phenol and an organic phase, which contains the main amount of phenol in addition to hail-boiling residues and some water. The organic phase is stripped and passed through a line 5 to the top of a connected column 6, while the aqueous phase is passed through lines 7 and 9 to the top of the column 6, a substream being passed through lines 8 and 13 to the top of a bladder 14 and 14, respectively. through lines 8 and 10 to the top of a column 11. The water drawn off from the top of the column 6 is passed in angular form through a line 12 to the column 1. The residual surface frail the column 6 consists after the evaporation of the water mainly of phenol with high boiling residue. This residual surface is peeled off and passed through a line 15 to a column 16, in which the phenol is distilled off from the residue and then passed through a line 4 to another column (not shown in the drawing), where it. worked up to pure phenol. The residue, which contains higher boiling point polymerization and condensation products, including cumylphenol and also dimethylphenylcarbinol saval as a phenol in an amount of, for example, 27%, is passed through a line 17 to the bottom space of, inter alia, 14, which Mlles at a. temperature of 220-350 ° C, preferably 270-290 ° G. Care must be taken that the temperature of approximately 170 ° C at the top of the bladder 14 is not exceeded in order to avoid that essential amounts of carbinol aver distill. This is converted at the elevated temperature in the bubble during water decomposition to α-methylstyrene, which is then recovered in the further course of the process as distillate from column 1 and after hydrogenation to the well can be used immediately in the oxidation step. A mixture, mainly consisting of styrene, acetophenone, phenol and water vapor, is drawn from the top of the bladder 14 and which, without flake-intermediate condensation, is passed through a line 18 to the lower part of the column 11. The selectable pumpable bottom space product from the bladder 14, which, above all, contains tar-like constituents in addition to only 0-1% of phenol, is passed through a line 19 to the bottom of the column 11. 25%) ingar. The temperature maintained at the top of column 11 is between about 90 and 130 ° C, while the bottom room temperature is between about 200 and 215 ° C. At this rate, acetophenone is still prevented from entering the anxiety stream drawn there. The vaporous product is then passed without intermediate condensation through a line 21 to the lower part of the column 1.

Exempel. For framstallning av en salufardig fenol av god kvalitet avdrogs enligt uppfinningen fran kolonnen 16 ett restflode med foljande sammansattning: Fenol % Acetofenon % Karbinol % Kumylfenol % Tjara % Per ton erhallen renfenol erhollos 250 kg av denna aterstod, dvs. aterstoden inneholl i enlighet med ovan angivna sammansattning: — — Fenol50,0 kg Acetofenon37,5 kg Karbinol37,5 kg Kumylfenol50,0 kg Tjara75,0 kg uppfinningen fordes denna aterstod fran kolonnen 16 over spaltningsblasan 14 4zich en liten destillationskolonn 11. Darvid Iiklades per ton renfenol 130 kg aterstod med foljande sammansattning, som avdrogs Iran Fend 8,45 kg = 6,% Acetofenon 36,4kg = 28,0 % Karbinol 6,kg = % Kumylfenol 2,6 kg = 2 % Tjara 76,05 kg = 58,% Av denna jamforelse framgar klart det utomordentliga resultat, som erhalles enligt det beskrivna arbetssattet. Detta resultat är speciellt gott pa grund av att det uppnas genom angformiga overdestilleringar utan att nagot storre behov av energi for hela destillationen uppkommer. Example. According to the invention, for the preparation of a marketable phenol of good quality, a residual flood with the following composition was deducted from column 16: Phenol% Acetophenone% Carbinol% Cumylphenol% Tara% Per ton of obtained renphenol recovered 250 kg of this residue, i.e. the residue contained in accordance with the above composition: - - Phenol50.0 kg Acetophenone37.5 kg Carbinol37.5 kg Cumylphenol50.0 kg Tjara75.0 kg According to the invention, this residue was fed from column 16 over the cleavage bubble 14 to a small distillation column 11. tons of renphenol 130 kg remained with the following composition, which was deducted Iran Fend 8.45 kg = 6,% Acetophenone 36.4kg = 28.0% Carbinol 6, kg =% Cumylphenol 2.6 kg = 2% Tjara 76.05 kg = 58,% From this comparison, the outstanding result, which is obtained according to the described working method, is clear. This result is particularly good because it is obtained by angular distillations without any major need for energy for the whole distillation.

Dessutom bearbetas utan speciella upparbetningsatgarder i den normala destinationsanlaggningen hela destillat,et fran spaltningsblasan 14 och kolonnen 11, utan att nagon som heist kvalitetsforsamring uppkommer. In addition, without special reprocessing measures in the normal destination plant, whole distillates are processed, one from the decomposition bubble 14 and the column 11, without any quality deterioration occurring.

Claims

Patent claim:

A process for recovering crude phenol from reaction mixtures from acid cleavage of isopropylbenzene hydroperoxide, wherein after separating the acid catalyst and distilling off the acetone, the hydrocarbons containing the mixture are separated by azeotropic distillation in the presence of water from phenol and the higher boiling phenols. in a subsequent column frail a predominantly acetophenone, dimethylphenylcarbinol saval as cumylphenol and other polymerization and condensation products containing residue and work up the phenol in one or more subsequent distillation columns to pure phenol while the residue obtained in the rafenol column is cracked by heat treatment, cracked by heat treatment the cracking is carried out in the bottom space of a column or in a lamp vessel and that the vapors from the cracking device without condensation are fed into a subsequent distillation column and into this column under reflux of the aqueous phase from the flask column, distilled in such a way that the acetophenone remains in the bottom of this column and the boiling boiling cracking products containing the vapors without condensation are returned to the hydrocarbon column.

2. A method according to claim 1, characterized in that the cracking is carried out in the water space in a column or in a lamp vessel under reflux of the water phase from the piston column. 3. A method according to claim 2, characterized in that the temperature radiating at the top of the cracking device is not allowed to exceed approximately 170 ° C. 4. A method according to claim 2, characterized in that a temperature is maintained at the top of the column connected to the cracking device. the range of about 90-130 ° C. 5. A method according to claim 2, characterized in that a substream of the aqueous phase in the bottom room product in it. column, in which the lower phenol-boiling constituents are separated from the phenol, is led to the top of the cracking device and / or the top of the column, which is connected to the cracking device, while the remainder in the aqueous phase and the organic phase before processing into ran phenol fares to a special column for separation ay yattnet. 6. A method according to claim 1, characterized in that the temperature in the top of the column connected to the cracking device is selected so that the acetophenone remains in the bottom space of the column, where one works without reflux in the aqueous phase. Request publications: column 11: Stockholm 196

3. Bungl. Boktr. P. A. Norstedt & Shner. 630069