DE1916149A1 - Process for the preparation of lactams from cycloalkanone oximes - Google Patents

Description

MTINTANWXUI DR. E. WIEGAND DIPL-ING. W. NIEAAANN 4 916149 DR. M. KOHlER DIPL-ING. C GERNHARDT MONCHCN HAMtUtO

27, Mail 1969

TEUFON, 33S47 * M ₀₀ MÖNCHEN 15, * ^f ' TElIOIAMMf. KAIFATtNT NUSSiAUM * T «A $ M It

W, H 191/69 - Ko / B

Toyo Bay on Kabushiki Kai aha iPokyo, Japan

Process for the division of lactams from Cyolo-

alkanone oximes

The invention relates to a technically advantageous process for the preparation of lactams from cycloalkanone oximes, in which the formation of ammonium sulfate as a by-product, which cannot be circumvented with the usual procedures, the recovery and can be prevented Reuse of neutralizing agents in an advantageous manner and not just in terms of work » stages, but also the operating facilities can be carried out, the desired lactams in high purity and can be obtained in high yields by simple separation and recovery operations, and the occurrence of adverse side reactions during the rearrangement and the neutralization stages in more advantageous Way can be avoided

In particular, the invention relates to a method for the production of lactams from cycloalkanone oximes by neutralizing the rearrangement reaction products, obtained by treating cyoloalkanone oximes according to the Beckmann rearrangement with sulfuric acid or oleum, so that the lactams are separated off and recovered become, where ·! the storage products with an oxide of

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1916U9

Calcium, magnesium, zinc or copper all metal oxides are neutralized and the lactams are separated and won through the Weutralislerumetsung formed metal sulphate of a thematic decomposition under conversion into the metal oxide is subjected and that metal oxide is again led to the neutralization level in the surttok

Volume ready process for separation and SajUDlung of the Laotam known, meanwhile the rearrangement reaction products, which in the following are rewarded as lactam-containing sulfuric acid solutions, which duroh Treatment τοη Cyoloslkanonoxlmen geaäl the Beckmann rearrangement old Teraohiedecen acidic agents, where sulfuric acid, Oleua and other elnsohlieeelioh even Lewis acids, whored, were obtained, are neutralized. If the production τοη as raw materials for synthetic fibers tob polyamide type, such as -Caprolaotam, o.Caprolaotaa and '-Laurlnlaotas: useful lactams from the corresponding Cyoloalkanonozlaen is desired industrially tob oesiohtpunkt the yield and quality of the lactams obtained as sulfuric acid or oleum Heagene of rearrangement applied.

In this case it is common practice to add 2 moles of des Use reagent per mole of starting oxime so that the rearrangement reaction is carried out sufficiently obtained lactam in the solution as from the following When the equation is ionized, it is in the form a salsartlgen substance τοη

908841/1679 _{ßAn Λ}

BATH ORIGINAL

That is why the neutralization of sulfur is satire but Separation of the lactam required.

Heretofore, the use of alkaline neutralizing agents such as ammonia and alkali hydroxides has been adopted or carbonates, for example caustic soda and sodium carbonate, suggested for this "neutralization stage". Ammonia in particular was used industrially for this purpose used; In this case the rearrangement agent is in obtained in the form of ammonium sulfate. However, the amount of ammonium sulfate recovered as a by-product is 1.3 to 3 tons per ton of lactam, although the quantities are more or vary less depending on the class of lactams ·. Therefore occur in the above procedures when using ammonia as a neutralizing agent Problems related to the recovery and * reuse of the as a lifting product in such large quantities ammonium sulphates formed and the cost of the desired lactams are considerably reduced by the the success or failure of the solution to this problem affects · * ..:

As a solution to this problem, Japanese Patent Application Laid-Open No. 8251/62 is a Process described in which the as a lifting product

1679

formed ammonium sulfate from thermal decomposition is subjected, in which it is converted into ammonia and sulfur " Dioxide is transferred and these are extracted. In British patent specification 1,021,709 let contain a suggestion where the neutralizing stage is omitted and instead of this the storage products are one Extraction with a solvent can be subjected and the desired lactams are separated However, both proposals do not give industrially satisfactory results.

For example, in the case of the "backward" procedures Ammonia recovery ratio low and the Separation of ammonia from sulfur dioxide is difficult Furthermore, since the separation is carried out in two stages, this process requires complicated and expensive facilities. Result from this There are numerous industrial disadvantages associated with this process.

Although the second method is an excellent method for separating and recovering the lactams from the Rearrangement reaction products occur the following new problems to be solved:

A) Ee is difficult to use the diluted rearrangement reagent to a concentration of 100 #.

B) Phenols with an association constant of

—2 x 1 "5 10 to 10 ■ are effective as solvents Suggested extraction of lactams from acidic solutions however, since these phenols take up some of the sulfuric acid during the extraction, the neutralization of the recovered lactams is from the extracted layer Required, if the neutralization for example is carried out using ammonia

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Ammonium sulfate as a by-product is formed, albeit the one The amount is only about a third of the amount of ammonium sulfate formed as a by-product in the usual process

C) Since the separation of the lactams obtained τοη the phenols are difficult and the products have poor properties, it is necessary to improve the purification level su

D) Therefore, additional expensive equipment is required in the industrial implementation of this process and the manufacturing cost of the end product is increased, although the amount of asuionium sulfate formed as a by-product is about one third the amount of ammonium sulfate formed as a by-product in the usual process is reduced.

Furthermore, a process is known where the rearrangement reaction is carried out in the gas phase, where instead of sulfuric acid or oleum a non-volatile acidic substance, for example phosphoric acid, Silicic acid, acid sodium sulfate and acid potassium sulfate or a solid acid catalyst such as boric acid-alumina or silicic acid-aluminum oxide can be used. However, in this process in the gas phase Reaktlonsteaperatur relatively high and consequently occur various detrimental lifting operations, for example thermal decomposition and polymerization easily and simultaneously with the intended rearrangement reaction on what causes the formation of byproducts in large quantities and a decrease in the yield of lactams. Furthermore, the products obtained contain various impurities, for example materials low boiling point, tarry substances and

8090 ^ 1/1679

Materials with a high boiling point · That is why I am achieving clay lactams τοη of high purity, which are sufficient as raw materials for eyηthetic Polyamide fibers are apt to be troublesome and disadvantageous Levels of purification required and the loss at Lactams during cleansing are bright

With regard to a method for producing τοη lactams, the disadvantage described above are · of the previous processes avoided _v particular the process for the preparation of lactams, the formation vcn Ammoniuinsulfat wc as a byproduct, which can not be avoided in the conventional processes, is verhindext , especially the recovery and reuse of the neutralizing agent advantageous and not easy, iMT with regard to the work stages, but also with regard to the workBaiisrück ε dunking can be carried out, in particular the desired lactams with high purity in high yield by simple separation and recovery operations can be obtained and in particular the occurrence of the disadvantageous side reactions during the rearrangement and the lieutralization stages can be prevented in an advantageous manner, the following investigations have now been carried out. It was found here that the goal set can be achieved in an advantageous manner if the neutralization of the storage reaction products is carried out using τοη oxide & n the specific metals described above. It was also found that the problems arising from the use of other ketallocytes besides those of calcium, magnesium, zinc and copper cannot be solved and that there is no real difference between the application of the used retail

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BATH ORIGINAL

and the ventilation of the above task.

Sa alkali oxides react with water and the system Making it strongly alkaline results in a drop in the yield of lactams due to hydrolysis or thermal degradation of the lactams during neutralization. Farther the thermal decomposition of the sulfates, which result from the neutralization, is very difficult. Farther is the handling of alkali oxides as such dangerous. As a result, the above objects cannot be achieved by using alkali oxides will·

When the oxides of the metals of the tin, iron, manganese, chromium and aluminum groups are used, the lactam-containing sulfuric acid ^{solutions are hardly neutralized at temperatures ranging from room temperature to 10O 9 C.} If a neutralization change occurs within this temperature zone, this is only the case to an extremely small extent. Even if the reaction is carried out at higher temperatures, the rate of conversion is very low and the lactams are largely degraded. Thus, the above objects cannot be achieved using oxides of metals of the above groups.

Magnesium oxide and zinc oxide are most preferred among the oxides of calcium, magnesium, zinc and copper used in the present invention. "If Magneeiumoxyd or Zinköxyä for neutralization the lactam-containing sulfuric acid solution are used, can, as the sulphate of these metals, which results from the neutralization solution, is highly soluble in water It is as easy to separate the crude lactam from the methosulfate solution as it is to separate using it

9O0Ö41 / 1679

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the bad got alkaline neutral remedies. be performed*

If copper oxide or calcium oxide are used » the sulfate of these metals has a relatively low solubility in water, but the separation of the lactams can can be easily performed by filtering the sulfate & b or the sedimentation is left to odsr the lactams with a suitable solution are suitable for dissolving the lactams, are extracted

Bas process ssur separation of the raw lactams can can be selected in a desired manner depending on the type of metal oxide used and there are none specific restrictions on the procedure the separation of the raw lactams on *

The invention is explained below with the aid of some implementation forms explained.

The method according to the invention is widely available on the production of ron lactams from eyeloelkanonoxiaen applicable, however e «is specially precautioned, d & e Method according to the invention on the Abtresmung imä SaisaLung that obtained from the storage reaction products Lactaiae to use which by treatment at least »one of the compounds Cyclohexanonoxim, CjclooctmnonoxiB and Cyolododecaiionoxime according to the B «ekmann Us3lag« ring not Sulfuric acid or oleua obtained *

The working conditions of Beckaasm storage with sulfuric acid or oleum are known. Therefore, the Beckmann CFW is & geruisg avoided for brevity of description "ine explaining,

The essential feature of the invention lies in the stage of neutralization of the Beckaajan rearrangement pro-

80984 1/167 9

products with an oxide of the metals OaIcium, Magnesium, Zinc and copper. This © neutralization stage * can be achieved using a standard stirred tank with a stirrer is equipped to be carried out

The metal oxide can be found in the diversion products in any desired form, for example as an aqueous slurry or as an aqueous solution containing the metal oxide contains, or in an In of an organic solvent disperse state.

To favor the Heutrallsierumsetsung it is preferred durohsuführen neutralization at about 30 to 100 * 0, in particular 60 to 80 ⁰ C under vigorous stirring. Eb 1st advantageous neutralizing perform in the manner that the pH is up to 6, preferably 5 kept the crude lactam at Heutralleationapunkt at 5 in the final stage of the neutralization point lon the easy separation and the high yield of L & otaa is It is advantageous to choose the amount of metal oxide supplied in such a way that the aqueous solution of the metal sulfate resulting from the neutralization is a saturated solution or a practically saturated solution.

After the neutralization phase has ended, the liquid phase of the crude Laet & ma is separated from the liquid phase of the aqueous solution of the metal sulfate and the crude Lagtau is collected. The aqueous solution of the metal sulfate formed during the neutralization is fed to a crystallization tank, where the metal sulfate is crystallized by crystallization under reduced pressure. If desired, other criteria can be used, for example condensation, ie combustion in a liquid or cooling system

009841/1879

The crystallization of the metal sulfate a is advantageous carried out in such a way that the metal sulfate is crystallized in an amount that the Hens the sulfuric acid contained in the sulfuric acid solution introduced into the neutralization zone is equivalent to. Generally, the metal sulfate will when it is out the aqueous solution is crystallized, obtained in a fora old crystal water. Therefore it is advised da · filtrate, from which the metal sulfate was removed, see below watch the Ifeuir & llsationst & nk back after the desired Amount of water is set and herewith reralsoht became"

The thermal gersetsung the crystallized metal sulfates is carried out according to methods known per se "For example, the sulfate leioht In the metal oxide and sulfur dioxide by mixing a source of carbon, such as coke or charcoal" and heating the semi sheep to 700 to 13OQ ⁰ C in a Zeroetzungsof® The metal oxide obtained is passed to the neutralization stage and reused. Furthermore, it is possible AUOH _5, the surüokgewonnen · sulfur door the Umlagerunge »tage re su use nachdes is transferred to Sohwefelaäure or other su

If 3 & h * 93i is the BrfiBäung, it is also ia ^ glish, di @ leutr & lisation in the absence το »Waes ^: @Sar in wsxt only one extremely large amount of« W & m®T ₉ di · sulphate «£ # · B'ur leutralisation irerwendetess Heta-llosya.® * 1b Eristaliwaes ·? contains, durohsufUhren »wob« i these «two cases mohfulgvM al®" pn ^ tisoh in absence tob W & ss ·? "besei @ hn« t, iaäeai a · Mspereion des Hetslloxyd «· in« inea orgmi & isohen L & amgamXt% 9l ₉ da «

909841/1679

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»Is capable of dissolving the lactame obtained, su der lac tamhal tiger. Schv.-efeleäurelbeung auge seist or by adding the solution to the above dispersion will. It is also possible to neutralize by adding the metal oxide in practically no form von Vv'aeeer on the sulfuric acid solution containing lactam and anechleate addition of the organic solvent » su to perform the system or this organic solvent to the lactam-containing sulfuric acid solution add and then practically in the absence of water to add the ketal oxide powder to the cash register «,

In these execution foraien using organic solvents can, since the raw lactam is simultaneously with the neutralization of an organic Solvent extracted »the separation of the lactase clay the metal sulphate can easily be carried out. Tuck versions are preferred for separating the crude lactams when neutralizing using a Metal oxide, the sulfate of which has a low solubility in water, is carried out, for example calcium oxide or copper oxide.

The embodiments described above under Application of an organic solvent can be easily carried out on an industrial scale because the metal sulfate is obtained in the form of crystals and any equipment for crystallizing the metal sulphates is unnecessary, which results in a simplification of the working processes.

Ee can all organic solvents that are inert to sulfuric acid and metal oxides and are capable of dissolving lactams, in the case of the foolish people AuQftlungforaen «! Ngeeetsfc verdeiu Al» der-

9098Ä1 / 167

-like organic solvents are ftethyienohlorid, di chlorst® than "chloroform, carbon tetrachloride, freon, dichloropropane, 1 _t 2 ~ dichloroethane _f 2richloräthyl" n _f tetrachlorethylene, 1 _# 2 _f 3-trichloropropane _t 1 ^ - »Biehlorbutan, 1.1 _$ 1 , -Irichloräthan, Toluol, Xylol, Hitrobsnaol »Chlorobenzene, Benzol, Chlorcyclohexan, Cyclohexan, üeealin, JSi tr α methane, acetic acid, Ä'thylacetai, Phenol, Cyclohexanol and the like. Listed. These organic solvents can be used either in the form of or in the form of more such organic solvents. With regard to stability against sulfuric acid and the ability to dissolve the lactars, the use of halogenated hydrocarbons is most recommended.

Me advantages of the experience according to the invention over the usual procedures are stiBamiaengefasati in the following

(A) In the case of rfindung8gesnäß «n the lactams without the formation of / umaoniurasulfat can be produced as a product of life.

(B) From CjeloalkanonoxiffiQn the corresponding Lactams of high quality and high purity were produced in high yields, as shown from the following fabello I shows where the Results of experiments according to the usual "method and according to the method according to the invention are listed*

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Table I. Asuaoniak process according to the invention Waaaer Zinc oxide calcium oxide usual procedure 96.0-97.0 Waeaer organic
solvent Heutrailsier-
■ ittel Caustic
soda 98i5-99.0 99, ü - 99.5 Neutralizing
solution solution
alttel water Neutralöa ~
tion yield
of Lactaa (%) 95.0-96.0

(C) The method according to the invention is opposite to the common processes in which the sulfuric acid is obtained in the form of clay asuaonium sulfate Eurüok, economically and technically advantageous,

(D) Ia comparison below the usual processes in which Asuaoniunaulfat is decomposed at "orfindungsgeaäiäen method any complicated and expensive equipment sur decomposition are not necessary, since the decomposition may be carried out in only one stage and the metallic oxides Xn higher ratios can be recovered .

Furthermore, the invention-based method can be easily implemented be carried out industrially

The following is based on the examples explained without the invention being limited to these examples is restricted

A solution of 35 6EW, -j6 & Caprolaotaa _e the hereinafter simply referred as Lactaa vird, 62 0EW "- £ Sohwefeleätir® and 3 S®w ~ 5i impurities was ER-.

909841/1679

hold by subjecting an oily cyclohexanone oxime hydrochloride, which was obtained by the Pkotonitroslerung of cyclohexane, to the Beckmann rearrangement in the usual way. 500 g of the above sulphuric acid solution containing the crude Lactaa were mixed with 270 g of zinc oxide with a purity τοη 99 # under wallowing from the outside and thereby obtained a condensed insole mixture. The condensed pulp thus obtained was mixed with 610 g of water to dissolve the zinc sulfate. Since an excess of zinc oxide floated in the solution, filtration was carried out. The filtered zinc oxide (10 g) was returned to the neutralization agent. The filtrate was heated to 90 ° and in an upper layer of 200 g of an oily aqueous solution containing 72.5 Lactaa and 1 # of zinc sulfate, and a lower layer of 1170 g of an aqueous zinc sulfate solution with a content of 2.4 # of the lactam and 43 "5 # zinc sulfate divided" The recovery ratio of the lactaas in the above neutralization stage was $ 99. The oily, aqueous solution of the lactam was added to the stage of the usual Laotaare fermentation, such as extraction, distillation, ion exchange or sterilization . On the other hand, the aqueous LösuBg of Zinkiulfat "was condensed by Srfriiß # η and thereby ftbdestilliert 200 g of water and crystallized ⁰ C with SO, and 510 g Zinkeulf ataonofejdrmt and 756 g Mutts ^ lnuge were separated · D» m distilled water, and the mother liquor were mn On the other hand, 213 g of crystallized Sinksulfataonohjdrats were thoroughly prepared from 15 g of coke and placed in a gas furnace maintained at 700%, while a molten gas of steam

909841/1679

and carbon dioxide, which contains 97 g of zinc oxide and 75 g gaseous echwefüge acid contained. The extraction ratio of the zinc oxide at the decomposition stage was practically quantitative and the ßewianungaverhaltnla the gaseous sulphurous acid was 965ε. The zinc oxide obtained became the neutralization stage recycled and the gaseous sulfurous acid was converted into sulfuric acid by a usual method transferred, whereupon the sulfuric acid continues in Üleum was transferred and to the stage of the Beokaann rearrangement des CyclohexanoBoiimhydroohloride was returned.

I forget

For comparison purposes, Example 1 was repeated using other metalloids, Di «Krgebniese are shown in Table II below together with the Results from Example 1 brought!

Table II

Neutralization «
middle tempera
tur C ^) Zinc oxide
(ZnO)
Beep. 1 Natriua-
ozyd
(NaO)
Versleioh Iron"
013rd
(PeO)
comparison Tin oxide
(SnO)
comparison Yield of crude
Lactam ($) Time (hours) 9S ₉ O 94.0 neutrali
sation was
not possible Neutrali
sation was
umtÖÄlioh t
•H
fi I Büekge
gaining »
Contract
(A) 700 700 WJi öS 4 * 1.5 1.5 H ^ R
α · ηβ
Φ O «β
Ml flVLJJf ^ Jsl 99.5 9
(no
Disintegrating
setsun ^)

909841/1679

_BM > ob * »» «·

A solution of 3 % of the lactam oleic acid 4 % impurity food was prepared ₅ While a cyclohexanone oxime industrially obtained from cyclohexanone and hydrcylamine sulfate was subjected to the Beoksiaim-Iisftageriing With Olfum in the usual orphan 500 g of the above solution containing the raw leotarn were subjected 1150 g of an aqueous 20% liquid sulfate solution in pourable form with a content of 300 g zinc oxide of 99% purity. During the neutralization stage, clay was removed from the outside so that the temperature of the liquid was kept at 45 °. The suggestion of the sulfuric acid solution containing the raw Laet & as was carried out at such a rate that the? pH of the neutralized liquid was kept above 3

When the addition was complete, the Syites meehaniesh was stirred at 45T for 15 minutes and the? pH de? neutralized liquid reached in de? Final stage 5. The liquid was then subjected to centrifugal heating and 56 g of the excess zinc oxide contained in it was separated off. Han allowed the neutralized liquid to ^{stand at 45 0} T and then it was poured into an upper layer of 200 g # i & e? oily, aqueous crust, which contained 73 ^ * ♦ "Laota" and Q, 8 £ Siaksulfftt, and a lower layer of 1694 g el & e? aqueous Sinkswlfatlösung oit a content of 14 _f 5 pounds of zinc sulphate and 2.5 liters of Laotaa separated.

The winning ratio of the laetaae at de? The neutralization level was $ 99, based on the sulfuric curative solution containing the raw Laotaa. Pie ulige w & frige

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«17 -

Dissolution of the lacta in the upper layer was carried out in the purification stage, while the aqueous. Zinc sulfate was condensed in the lower layer duroh Urhitaaa and 300 g of what was removed. "The condensed" solution was then subjected to crystallization at 45 ° C. and 460 g of crystalline zinc sulfate hexahydrate and 650 g of mother liquor were obtained mother liquor were au represents. recirculated Äeutraliaationsstufe · the krietalline Zinkaulfat thereby obtained "H" rxakhydrat was übarführt at 3GO ⁰ C dried and dissolved in anhydrous Siaksulfai, which then was converted to gaseous sulfuric 'acid and as transferred into the same manner in example 1. "2in & 3xyd . The sulphurous acid was converted into sulfuric acid and added . the Beckmann rearrangement. The Sinkoxyd was returned to the ffeutrallsieretufe so that both were used repeatedly.

Belsjgiel } _m

500 g of a crude lactam-containing sulfuric acid solution of the same composition as that used in Example 1, containing crude lactam, and sulfuric acid solution, were poured in 1100 g of water in such a way that the temperature was not up to 1Q * C rose and xu the v "rdünnten solution 250 g Ziiücoxyd over 1 ₉ 5 hours, with stirring sugogsben" wherein ate tempera door ⁶ at 10 C was maintained by cooling. The liquid “neutralized” in this way showed a pH of 2.0. Si · neutralizes «Lösuag litS süsjj btl 10T etthen * whereupon you see in« an obese layer of 185 g · 1αβ £ oily water

gen solution which contained 73ife - * e * lactam and O _s 5 / zinc sulfate, and a lower layer of 1665 g of an aqueous. 2inkaulfatlo "3ung, which contained 3O ₉ 5 $ zinc sulfate and 2.3 yi Laotians" subdivided "Ba & recovery ratio of the lactcu & a with which iieutralisatioiiösfcui'e was 99;" The aqueous zinc sulfate solution of the lower layer was subjected to crystallization in the same manner as in Example 1 to obtain zinc sulfate heptahydrate, which was then dried and converted into gaseous sulfuric acid and zinc oxide. The gaseous sulfuric acid was converted into sulfuric acid and the Beckxiaiiii-UiclagurungBßufö supplied "while the intoxication was returned to the stage of neutralization of the raw!" ActöES.

500 g of a rohea Lectam containing S-chwefeleäiir · - löaung with the same 2u £ asiinenBetsung _t were as in Example * u 820 g of water was added in such a manner, the DTSS ieiaperatur below 5QK was maintained. 130 g of magnesia oxide were added to the Terdünnt® B solution and neutralization was carried out. while the gate standing leutraliaation ®%:% @ Wänaeentwicklung feeöbaehtet was «was cooled by sueasu · so that the! temperature of the Syateas was kept below 50 ° above sea level. The pH of the neutralized coating was 3 _β 5 · Msm. li «@ the neutralized Plüssigkelt at SCR 'atOh-SB ₉ whereby it is calibrated in an upper layer of 2 ^ 0 g of an oily Meiusg, Ulm 67% Imotam and Q ₉ Q ^

171673

sulfate, and a lower layer of 1200 g of a magnesium sulfate solution with a content of 31 Magnesium sulfate and 0.5 # lactam.

The absorption ratio of the Laota tea at the reutilization stage was 99 #. The oily aqueous solution The lactams of the upper layer were sent to a subsequent purification stage, while the Hagnesius ~ sulfate solution of the lower layer of crystallization was subjected to thereby obtaining 100 g of crystalline magnesium sulfate hexahydrate. This was then at 5000C dehydrated and carbon in the amount of 2.1 Moles per mole of magnesium sulphate, acid acetate and aneohlessend at 1200T tersetite, with 28 g gaseous sulphurous Acid and 17.5 g of magnesium oxide were obtained. Bas recovery ratio both τοη gaseous sulphurous Acid as well as τοη magnesium oxide was practically 10OJt at the decomposition stage.

The gaseous sulphurous acid obtained was converted into sulfuric acid and on the Beotasann-U * - storage of the cyclohexanone oxide, while the Zinkoxyd sur Reutralisatlonsstufe surüok was carried out. As a result, both were used repeatedly.

example 5

A solution of 36% by weight of caprolacta, which is subsequently derived from lactate, 60 % of sulfuric acid and 10% impurities was obtained. Cyolohexanone oxime hydrochloride, which was obtained by photonyltronation of cyclohexane, was subjected to Beokoann urination in the usual way became. 500 g of the crude Xi & ctaa-containing sulfuric acid prepared in this way were added to a suspension for 40 minutes

9098 A 1/1679

290 g of zinc oxide in 750 μl of chloroform were added to the contents in a kettle equipped with a stirrer and cooling tube. The rate of addition was regulated in such a way that chloroform was kept in the boiling state. When the addition had ended, stirring was continued for 20 minutes to complete the neutralization reaction. The pH of the neutralized liquid was 5 »0. The neutralized fluid was "put into filter paper". The precipitate obtained was washed 3 times using 500 aal of chloroform each time. 590 g of zinc sulfate honohydrate were obtained as a precipitate, which contained 40 g of unconverted excess zinc oxide. On the other hand, the filtrate was mixed with the washing liquid, whereupon the chloroform was evaporated and 181 g of crude lactam were obtained and used for the suspension of zinc oxide. Since "crude lactam was mixed with 2 g Itznatron and subjected to vacuum distillation at 170 ⁰ C and 17 mm Hg. 179 g of crude lactam and 2 g of Bücketand were obtained. The lactam recovery ratio by neutralization and distillation was 99 * 556.

Then the 590 g were Zliiksulfat which nlchtumgesetstee Excess containing zinc oxide, 0 dried and then thermally zereetzt at 300 * and at 770 ⁰ C in the presence of 30 g of activated carbon and thereby obtain 190 g of sulfur dioxide and 285 g Zlnkoxyd. The recovery ratio of sulfur dioxide and zinc oxide in the decomposition process was 97% and 98.3%. The aurtiek-recovered sulfur oxy was converted into oleum and the step "ümr B" okmann rearrangement de "Cycloheianonoxiahydrochloride was returned.

while the tin oxide was added to the stage of neutralization of the sulphuric acid solution containing the crude lactam. In this way, both materials were repeatedly turned around.

Example 6

50 μg of a crude Lactaa-containing sulfuric acid solution old of the smooth composition "* i · in Example 5" were generally obtained over 60 minutes in a suspension of 30U g of zinc oxide in 750 μg of a refining agent ie volume obtained from 1.2 -Diohloropropane and carbon tetrachloride sugesetst »which in one) Oefttß equipped with stirrer and cooling tube included were "The ease of addition of the sulphuric acid solution containing the crude lactae was adjusted" so that the Misohlusungsalttel Ib simmering was held.

When the addition was completed, stirring was continued for 30 minutes via the end of the neutralization. The neutralized liquid was subjected to centrifugal separation and the zinc sulfate hydrate was separated from it. The zinc sulfate hydrate was washed 3 times using clay, 300 si each g solid zinc sulfate hydrate obtained. The solid obtained was * C sersetst dried at 300 ¹ C and at 700 and thereby obtained 113 g of anhydrous sulfuric acid, 106 g Sohwefeldioxyd and 298 g of zinc oxide "Di · KückgewinnungsTerh &-relations of sulfur dioxide einschllesslich anhydrous sulfuric acid and zinc oxide were in the above Zersetsungesfuf · 98J & b «W. 99t5 *. £ * · containing · anhydrous sulfuric acid · Burüok obtained · sulfur dioxide was converted into oleum

9 09S41 / 1679

and "ur Beckmann rearrangement of cyclohexanone oxime" hydrochloride reused, while the zinc oxide was returned to the neutralization stage.

The piltrate was mixed with the washing liquid, then the solvent was evaporated off and 185 g of crude lactam were obtained. That crude lactam was rermischt with 2 g of caustic soda and then subjected to vacuum distillation at 170 ⁰ C and 13 mm Hg, while 179 g of pure lactam and obtain 6 g of residue. The recovery ratio of lactam during neutralization and distillation was 99.5-A.

Example 7

500 g of a sulfuric acid solution containing the crude lactam and having the same composition as in Example 5 were added in the course of 60 minutes to a suspension of 260 g of copper oxide (CuO) in 500 ml of 1,1,1, -trichiorethane, known under the name Chlorothene im Trading is, sugesetst · The speed of adding the that Crude lactam containing sulfuric acid solution was so set that the trichloroethane was kept boiling. When the addition was completed, stirring was continued during Continued 30 minutes after the completion of neutralization.

The neutralized liquid was subjected to a centrifuge

Subjected to galvanic separation and granular copper sulfate hydrate separated, which was then washed 4 times using 300 ml of chloroform each time. 560 g of copper sulfate hydrate were obtained. This was then at 300 C ⁴ dried, mixed with 50 g of carbon and zersetst at 68CW, wove "! 192 g of sulfur dioxide and 258 g of copper oxide were obtained. The volume ratio of sulfur dioxide and copper oxide was 98.0 pounds

909841/1679

-23- 1916U9

b * w »99ί, 2 55, Baa sur & elcgewonneiie Scltwefeldioxycl was In Oleum transferred and to the stage of the Beokmann rearrangement des CyololiexanonoxinihydroeliloxläiS refilled, while the copper oxide but Metitralieationsstufe surüek performed became"

The filtrate was mixed with the washing liquid and then the friehlorethane was evaporated and 183 g of crude Iac tarn were obtained. This was mixed with 2 g of caustic soda and subjected to vacuum distillation at 170 C and ¹ mm Hg 13 and thereby obtain 179 g of pure Laotaia and 3 g of residue. The lactam recovery ratio during neutralization and distillation was 99.5%.

Example 8

500 µg of a sulfuric acid solution containing the crude lactam and having the same composition as in Example 5, "250 g of kupiearoxyä in 600 ml of trichlorethylene were added over 60 minutes to a suspension of iron, which were contained in a vessel equipped with a stirrer and cooling tube," rare "the 2ugabegeachwindiglceit of the crude lactam containing Schwef was elaäurelöaung adjusted so that it was held τοη sow temperature trichlorethylene below 30 ⁰ C with a cooling" Hach completion of the addition became the Ilühren for 30 minutes at 30 ^ 8UR completion of fieutrali " «.-Tion continued. The neutralized Plüseigkelt was subjected to a centrifugal separation, and pulverulent copper sulfate hydrate was separated, which was then washed 3 times using 3QO each of frichloxethylene. The resulting hydrate was 270%

909841/167 9

1916U9

dehydrated and dried, mixed with 20 g Koke and thermally decomposed at 7OQ ⁰ C and thereby obtain 190 g of sulfur dioxide and 245 g of copper. The recovery ratios of sulfur dioxide and copper oxide in the decomposition stage were 97%. 98 #, the recovered sulfur dioxide was converted into oleum and the cyclohexanone oxime was returned to the Beckmann rearrangement stage, while the copper oxide was returned to the normalization stage. In this way, both were used repeatedly,

The filtrate was mixed with the washing liquid, whereupon the trichlorethylene was evaporated and 185 g of crude lactam were obtained. The obtained roh® lactam was mixed with 2 g of caustic soda and the V & kuu »» subjected to distillation at 170 ⁰ T and 15 mm Hg and thereby obtain 179 g of crude lactam and 5 g of residue. The & © - winnungsverhältnis was of lactam during the neutralization and distillation 99 _f 5 £.

Example 9

A solution of 35 $ '-: .- Caprolactas, hereinafter referred to as lactam, 63 % sulfuric acid and 2 ^ impurities was obtained by adding cyclohexanone oxime, which had been obtained by dissolving cyclohexane and hydroxylamine sulfate, to the Beckmann rearrangement in was subjected to the usual way. 50ö g of this on © manner obtained the crude lactam-containing sulfuric acid solution was at 78 C during ⁸ ron 90 minutes au a suspension of 130 g of magnesium oxide in 1000 ml of a mixture of benzene and aseotropen Gyclohex & n

909841/1679

BATH ORIGINAL

(Weight ratio 49 »7: 50.3) were added, which were contained in a vessel equipped with a stirrer and cooling tube. After the addition had ended, stirring was continued at 60 ⁸ C for 60 minutes. The neutralized liquid was subjected to centrifugal separation, and granular magnesium sulfate hydrate was separated therefrom. The separated hydrate was washed 5 times using 300 ml each time of the azeotropic mixed solvent. Sabers obtained 450 g of magnesium sulfate hydrate. This was ^{dehydrated at 500 °} C. and dried, mixed with 20 g of charcoal and thermally ^{decomposed at 1200 °} C., 195 g of sulfur dioxide and 128 g of magnesium oxide being obtained. The recovery ratios of sulfur dioxide and magnesium oxide in the decomposition stage were 95 # and 98.5 #, respectively. The recovered sulfur dioxide was in Oieum Convicted and to the stage like "v Beckmann rearrangement of Cyclohexanonoxlas suruckgefiilsst ₉ Curr @ nS the magnesium oxide to Heutrallsationsatnfe SOTÜekg © leads sti? De · a result, both were repeatedly used *

The filtrate sausage is mixed with the washing liquid, the Miscblogr-iQgsinmittel evaporated at the Gliessond and 180 g of crude lactam obtained. The raw laotaa obtained was mixed with 2 g of itsnatron and subjected to vacuum distillation at 170% and 3 mm Ug and 173 g of crude lactam and 9 g of residue were obtained. The recovery ratio of lake lactams during neutralization and distillation was 98 , 85ε.

Example 10

500 g of a sulfuric acid solution containing the raw lactam with the same composition as in Bei »

90984171679

game 5, were added in the course of 30 minutes to a suspension of 173 g calcium oxide in 900 ml Benaol, which were contained in a reaction vessel equipped with a stirrer and cooling tube. The speed of access the sulfuric acid solution containing the crude lactam was adjusted so that the benzene in the The boil was kept. After the addition was complete, heating was continued for 30 minutes with the benzene was kept in the boiling state. The neutralized® liquid was cooled to 30 °: and then filtered, The precipitate containing the calcium sulfate was extracted 4 times using 300 ml of benzene each time washing · The filtrate and that used for washing were subjected to distillation, thereby recovering 178 g of lactam. The recovery ratio of lactam was 99.0 ^

The filtered Calciuasulfathydrat was dried at 2QO ⁰ C and then thermally decomposed ^er * at 1700 for 2 hours in the presence of 75 g of coke in a Zersetzungsofsn. Here, 170 g of calcium oxide and 191 g of sulfur dioxide were obtained "The lückgswianuiigsverliältniss © calcium oxide and sulfur ioxyd cheating" 98,3S & bsw ₀

Sas recovered GßXeixxmozjä was "snr Emu - = - trallaation of the crude lactam enthelteadea Schwefelsäurelösuag reused _f while there © transferred to Sehwefeleäure was Nmae to

storage of the cyclohexanonozime refurbished

90 9841/16 79

ORIGlNAL BATHROOM

Claims (1)

1916U9 Patent claims , 1. A process for the preparation of lactams from Cycl ^ oalkanonoximen, wherein the treatment of the Cyoloalkanonoxime according to the Beckmann-UiBlagerung with Rearrangement products obtained from sulfuric acid or oleum are neutralized and thereby the Lactaae are separated and obtained, characterized in that, that the rearrangement products with an oxide of calcium, Magnesium, zinc and / or copper are neutralized with the separation and recovery of the lactams Metal sulfate formed during the neutralization of thermal decomposition with conversion into the metal oxide is subjected and the metal oxide to the Heutralisaticnsstufe is returned. 2. The method according to claim 1, characterized in that that the neutralization in a to dissolve the Umlagerungareaktionsprodiakte in the presence of a Amount of water that is not the amount dee in the metal oxide contained water of crystallization, i.e. practically in the absence of water «suitable organic solvent is carried out. 3. The method according to claim 1 © the Z _9, characterized in that the neutralization is carried out at temperatures in the region of 30 to 100 ^er1 . 4. The method according to claim 2 or 3, characterized in that that a halogenated hydrocarbon is used as the organic solvent. 5. The method according to claim 1 to 4, characterized in that the neutralization is continued until the separated lactam shows a pH of 3 to 6. 909841/1679 6, procedure aaoh anepruoh 1 to 5 »thereby characterized that the thermal decomposition dee Metal sulfates by heating to temperatures la range 700 to 1300% in the presence of a source for clay Carbon is carried out 909841/1679 SAD ORIGINAL