DE2025172A1 - Process for the preparation of N alkyl lactams - Google Patents

Description

VEB Leuna-Werke "Walter Ulbricht" Leuna, 13.6.1969 Patent Department DC. Bo / Str.

LJ ?. 929
Process for the preparation of N-alkyl lactams

The invention relates to a method for obtaining N-alkyl-substituted lactams, especially N-methyl lactams, by alkylation of the corresponding unsubstituted Lactams.

It is known that NH $ alkylated lactams can be obtained by reacting To produce lactones with primary amines (WD-AS 1 265 159). This procedure is complex, since the lactones are produced by special synthesis processes that run over several stages must be won. Furthermore, no high yields are achieved.

It is also known that N-alkyllactarns can be produced by the action of alkyl halides on metal salts of lactams (J. Tafel and D. Wassmuth; Bar. Dtsch. Former Ges. ££ »2839 (1907)). The conversion of the lactams which we have overlooked with dimethyl sulfate has also been described specifically for obtaining N-methyllactams (E. Späth and H. Bretschneidert Ber, German former Ges. § ±, 330 (1928)). This «methods require the use of large amounts of solvents as well as a lengthy» and complicated processing of the heak «

tionegemieeh ·, 009883/2081

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Furthermore, it was ready karzustellen voi> g®eehlag6ß ₉ M-Alkyllaetam® by gas phase reaction of the unsubstitttifften lactams with alcohols in the presence of viasees? Nucleating catalysts at temperatures around 300 ⁰ C, taking as an example the reaction of Pyvrol £ eon "(2) with methanol, which leads to N-methyl «pyrrolidone» (2), is indicated (USP 2,674,602). Here, too, the yields are significantly low (Tab. Ό «

The purpose of the invention is to produce m ₉ N-alkyllactarns in a better yield and in a simpler way.

The invention is based on the task, a technical one Applicable Synth®e§m% l £ © h.keit for N-alkylated lactams find that is based on! deeply accessible starting products, is advantageous with regard to the raakisioaaftiteung and work-up of the reaction mixtures and more favorable yields results

According to the invention aa nitrogen atom substituted lactams dureh alkylation. © ines corresponding lactam unsübstituierten Dadui? @H prepared by the unsubstituted lactam is reacted with a synaetfischen Dialkylather in the presence of a dehydrating · catalyst at temperatures between 200 and 400 ⁰ U to the reaction. The Auagange products used are preferably unsubstituted lactams with 4 to θ carbon atoms in the ring.

001833/2081 ^->

It is also advantageous if, in the process according to the invention, all the alkylating agents used are symmetrical dialkyl ethers in which each alkyl group has 1 to 4 Contains carbon atoms.

Catalysts which can be used for the process according to the invention are, for example, bauxite, silicates, phosphates, sulfates, preferably aluminum oxide, which can optionally be applied to the support material or modified by suitable additives.

Furthermore, it is favorable in the case of the process according to the invention to work ^{at a reaction temperature of 250 to 350 ° C.}

The implementation of the process according to the invention is designed In the case of methylation, calibration is preferred in such a way that Lactam is metered into the apparatus in liquid state and the gaseous dimethyl ether is fed in at the same time. The mixture passes through a preheater to the catalyst arranged in the Fe st bed, «0 the reaction occurs. That the The catalysis leaving the reactor * is condensed and then distilled in the known manner. disassembled. The not wrong « · Dimethyl ether can be put into circulation and again can be used in dl · reaction. The amounts of the unreacted lactam recovered by distillation can are also fed to a renewed implementation.

-4-009883 / 2081 '

Suitable N-alkylated. Lactams can be used in many ways, for example as selective solvents or al « Intermediates for synthesis.

The advantages of the procedure according to the invention, in particular the method for the methylation of lactams under bin rate of dimethyl ether in comparison to the known process of alkylation with methanol, are in the fact that higher yields of alkylation product in a single pass at the same time higher catalyst loading achieved and Great savings can be achieved on the cost side. For explanation, the results are compared, welch® in the same test facility for the methylation of £ -Capro « lactam using methanol or dimethyl ethers ale Al kylierungakomponente and aluminum oxide as a catalyst were obtained in a single pass. The molar ratio of alkylating agent to lactam was always 2: 1

Table 1

Load temperature conversion to H-methyl «if«> capr © «

(g £ -Caprolactam / Oq \ lactam

ItSS; ¹⁷ "" * ⁰ "- Mkyllertmg ndt alkylation» *

· Methanol dimethyl ether

0.1 300 50.6 * 7O ₉ 8 * '. "■'

0.2 300 44.5 * 63.5 *

320 47.7 * 77.2 *

0.3 300 43.5 * 52.3 *

320 46.4 * 72 * 1 *

009883/2081

IiP 925

Similar favorable results as the € "Caprolaotaa methylation with Dimsthylather are also obtained in the Methyllerung of pyrrolidone (2) with dimethyl ether. Even when using higher symmetrical dialkyl ethers * "for example diet hy 1", disopropyl, dibttyl and diio-butyl ethers, the corresponding alkylation products are formed in good yields. "

A further advantage of the process according to the invention, in particular the method for the preparation of τοπ B-methyl-ε-oapYO-lactam, is that the Auegange products are easy and are technically accessible in large quantities ·. Dime thy lathe » is a very cheap, mostly unwanted product of the compulsive seizure at the Hethanoleyntheee, which, in the absence of versatile chemical applications, is often used as Heating gas is used · £ ~ Caprolactam is used in large Itafang technically produced, whereby it is not necessary for an application according to the method according to the invention, higher Requirements for the purity of the lactams to be used to ask, you can also use fractions at least use higher quality

The finding should be based on the following examples to be explained in more detail «

009883/2081

- 6 Bel «floor 1

H first 1 Y , u ng ,, j ο, η «JSb

With a payable ¥ © yi? Ateg®fl§, d-Gapspolactaia in an * amount oa 1200 g isi ¥ allowed of 7.5 hours in di§ fereuehsüpparatus * elndoeittratus, if there was a reaction tube, where there was 32Θ \ tisgiUfiort what? and the catalyst (Alimiiiiuii & sid) contained in ® ± & ®% H @ ag © of 8oo g. At the same time, & ®v Anlag® 4a §4 l / ^ td «Bins · thylether added« Mbs & mi ä®s
very weak ³ StiekstoffetooB iy ^ efe
Daa the reactor veip3 »© E @ © ßfi © iredsÄtgaHisefe ossd® diivea ment condenses nad Qia @ 2? d @@ tillatif © a & va £ as> processed · According to the AMssflilidroß d @ i? kaaptalekliela made of l®tiaanol and water l) consisting of © a ni @ S £> igei @ d @ nde & l & t @ lie giog b @ i 105 bie 115 ⁰ O / 10 SBB öae foM © ® «Hethjl« »^» € af ^ @lf »e ^< laJ8-in one? Quantity τοη 1061 g übe? ·

Ale higher «iedendtf I ^ shares wra? Ä @ at eime ^ Sisie ^ en ^ e ^ ata ^ τοη 138 - 140 ⁰ O / 141 m £ * · * €» prolaefa® ia_ @ iia®i? Meng® clay 196 g (16.3 S6 _; bessegta auf ü © Einea% zü @ »ge)} BtarUekgöwonnen« These 196 g C-Oaprelaetaii were converted under the 'gl @ l @ h @ n working conditions of a brief conversion segefütef _o ßabei obtained after similar workup 176 g of voton I "Hetfeyl- € caprolactam, 32 g ^ -Oaprolaetaii nice m & h ± not implemented. Wherein obtained 1212 g (98% of the used Hing ·) "ine * Eroäukt · after two Dureheätzen ln» gs @ AAF g®w @] m®i »a 1237 g of the crude product ·· wurden.erneut.destilliert"

009883/2081 τΤ

LP 929

dae a purity τοη above 99.5 * in gas chromatographic analysis as · (Kp _{# 10} 105 to 106 ⁰ Cj

1,481Of d? ' 1.012). The conversion of the έ-Caprolaetama used to H-Metnyl ^ caprolactam was 77.2 % after a single throughput, 89.9 % after two throughputs, whereby the amount of the pure alkylation products obtained after the redistillation serves as a reference basis.

With «Hall 2

Herate ilung τοη Η — Methvlovrrolidon— (2)

A total of 901 g Py * rolidon- (2) were in an amount τοη 120 g / hour. gladly am with 64 1 / hour Doeethyl ether at 300 ⁰ O into the apparatus described in Example 1. The catalyst obtained was separated by distillation, the crude H-methylpyrrolidone- (2) initially obtained was obtained by renewed distillation in a purity determined by gas chromatography of 99.7 * (bp _{# 10} 80 ° C | U ₀ ²⁰ 1, 47021 d ^ ° 1.029) · The amount of pure H-methylpyrrolidone- (2) obtained was 816 g, which corresponds to a yield τοη 77 * 7 %. 161 g of pyrrolidone- (2) (17.9 *) were recovered without being used (boiling point _-10 120 to 122 ⁰ O,

009883/2081

Example 3

Her ate l l uj ^ ff γοη H-Ethyl - ^ - caprolactan

In the course of 7.5 hours at 320 ^° C., a total of 600 g of ε-caprolactam and 785 g of diethyl ether were fed to the experimental apparatus described in Example 1. In the DISTILLA · tive processing of the Katalysats were after re Oesül · lation of the initially resulting crude product 497 g N-ethyl-icaprolactam (bp _{# 15123} bi · 124 ° C | ²⁵ 1.4775 n _D | DJP 0.981; gaschromatographic purity > 99 %)% that corresponds to a yield of 66.0 %. 157 g of unreacted 6-caprolactam (26.2 %) could be recovered and fed back into the reaction.

'■' -9-009883 / 208T

Claims (5)

Claim » J process for producing at the nitrogen atom by express "alky! Group substituted lactams by alkylation of a corresponding unsubstituted lactam, characterized in that the unsubstituted lactam with a symmetrical dialkyl ether in the presence of a wasaerab- ^ cleaving catalyst at temperatures between 200 and 400 ⁰ C for Reaction is brought 2. The method according to claim 1, characterized in that unsubstituted lactams with 4 are used as the starting product uses up to 8 carbon atoms in the ring. 3 · The method of claim 1 and 2, characterized in that there are used as the alkylating agent symmetrical dialkyl ether in which each alkyl group has 1 to 4 carbon atoms, ^"w atoms. 4. The method according to claim 1 to 3, characterized in that that as a dehydrating catalyst, aluminum oxide is used. 5. The method according to claim 1 bie 4, characterized in that that the reaction temperature is in the range of 250 to ⁰ O 009883/2081