DE2158615A1 - Process for the preparation of cyclic imide acid esters - Google Patents

Description

Gelsenkirohen-Buer, November 24th, 1971

Veba-Chemie Aktiengesellschaft Gelsenkirchen-Buer * 2158615

Process for the preparation of cyclic imido acid esters

The invention relates to a new catalytic process for the production of cyclic iraidic acid esters, which-also al3A2-0xa- ' zolines and 4H-5,6-dihydro-1,3-oxazines, from nitriles and aminoalkanols.

Numerous processes for the preparation of such compounds are described in the literature, but only a few of these processes work from nitriles. For example, nitriles have been reacted with diols in the presence of sulfuric acid to form oxazines (Tillmanns, Ritter: J. org. Chem. 22, (1957), 839). Nitrile-SnCl ^ adducts react fourth with epoxides in the presence of sulfuric acid to form oxazolines, as determined by Y. Hayashi, Sh, Neda and R. Ode. have (J. Chem. Soc. Japan, Pure Chem. Sect. (Nippon Kagaku Zasshi) 90. (1969), 9, 946), but only low to moderate Yields can be obtained because the resulting oxazolines polymerize under the reaction conditions.

The production of A2-oxazolines from nitriles and aminoalkanols is described in U. ^^ patent 2,402,193. Since the reaction is very slow in the absence of catalysts, will the reaction is accelerated by adding an alcoholate of an alkali metal or alkaline earth metal and alkaline compounds. Despite the addition of such catalytically active compounds, this process is economical because of the low yield not interesting.

- ² - ORIGINAL BATHROOM

309822/1139

It has now been found that cyclic acid esters of the general formula can also be used

R ¹
\

| "H- η

in which η = 1 or 2 vmd R is an aliphatic cycloaliphatic, araliphatic, heterocyclic aromatic or

_R} . -Rest can mean

(CR'R «) _n

f
R "

and R 'and R "can be identical or different radicals from the group consisting of hydrogen, alkyl, aryl, aralkyl, cycloalkyl, OH, COOH, CN or halogens, can be obtained in better yields and in a shorter reaction time if the nitriles are optionally mixed with C. -substituted C ₂ - or C -, - aminoalkanols in the presence of salts of inorganic and / or organic acids of metals of the 1st and 2nd main and subgroups of the periodic table.

This results in ammonia being split off when used of monoethanolamines 2-substituted A2-0xazolines, while one 4H-5,6-dihydro-1,3-oxazines which are 2-substituted with 1,3-propanolamines are obtained. The scheme below shows the reaction in more general terms Formulation:

-CN +. H ₂ N- (CR ¹ R ") _m 0H NH ψ UH,

H ψ NH ₂ C-NH- (CR'R ^J ') _m OH £ _ ^ -C = N- (CR ¹ R ") _m 0H

BAD ORlGiMAL

309822/1139

In this scheme, m means - n + 1. With m = 2 oxazolines are obtained, with m = 3 oxazines. R ^{ and R "are preferably H. However, they can also be identical or different radicals from the group consisting of alkyl, aryl, aralkyl, cycloalkyl, OH, COOH, CN or halogens.

The nitriles are in such a molar ratio with the alkanolamines implemented that per cyano group 1-3, preferably 1.2-2.0 Moles of alkanolamine come.

The reaction according to the present invention is carried out at temperatures in the range 15-180 ⁰ C, preferably between 90 150 ⁰ C is performed.

As optionally C-substituted C ₂ - and C ^ aminoalkenols, for example: Monoethaiiolamine, 1,2- and 1,3-propanolamine, etc. The possible substituents of the aminoalkanols are in the definition of R ^! and R ".

The process according to the present invention can be carried out both with aliphatic, cycloaliphatic, araliphatic, aromatic and heterocyclic nitriles. Suitable aliphatic nitriles ^ are, for example mononitriles such as acetonitrile, propionitrile, Athoxymethoxyacetonitril, 3-chloropropionitrile, .beta.-methoxypropionitrile, inter alia, οί-ω-dinitriles such as malononitrile, Succinodinitril, glutaronitrile, Methylglutarsauredinitr.il, adiponitrile, "^ o (,% -Trimethyladipinsäuredinitril, oC, g,) f -Trimethyladipinsäuredinitril, Pimelinsäuredinitril, Suberdinitril and others as well as those with double bonds in the aliphatic radical, such as Dicyanbutene and others

Suitable cycloaliphatic nitriles are tetrahydrobenzonitriles, 1-cyano-cyclohexane, dicyano-cyclohexane, among others.

BATH ORIGINAL 09822/1139

Examples of suitable nitriles with aralkyl radicals are phenylacetonitrile, Phenoxyacetonitril, 2 ~ Phenylpropionitril, Phenyldiraethylacotonitril, 3-phenyl-butyric acid nitrile and others

Suitable heterocyclic nitriles are the cyanopyridines, such as 3-cyanopyridine, as well as 3- and 4-cyanquinoline, 3- and 6-cyanindole, 2-cyano-tetrahydrofuran, 6-cyano-coumarin and others

Both aromatic mononitriles and dinitriles or polynitriles are suitable for carrying out the process, ie, for. B. benzonitrile, the naphthonitrile, isophthalonitrile and terephthal iodinitrile, the phthalcdinitrile, such as 1,3> 5 ~ tricyanobenzene, W 1,2,4,5-tetracyanobenzene. Examples include those which, in addition to the nitrile group, have one or more substituents which are chemically inert under the reaction conditions, such as tolunitrile, p-isopropylbenzonitrile, halobenzonitriles, e.g. 4-chlorobenzyl cyanide, nitrobenzonitriles, hydroxybenzonitriles, etc.

When reacting nitriles with alkanolamines to give the corresponding cyclic imidic acid esters is used to accelerate the Reaction and to achieve economical conversions and yields the use of catalysts of considerable advantage, especially In the case of aliphatic and cycloaliphatic nitriles and substituted alkanolamines, a reaction is only successful the use of catalysts is possible. In practice, however, all nitriles are amenable to this reaction, albeit their reactivity is different.

Suitable catalysts for this purpose are salts of inorganic and / or organic acids of metals of the 1st and 2nd main and subgroups of the periodic table. Of the inorganic salts, the halides, rhodanides, sulfates and thiosulfates are particularly suitable. For example, as halides LiCl, NaBr, LiBr, KBr, MgCl ₂ , as sulfates Li ₂ SO ₄ , Na ₂ SO ₄ , K ₂ SO ₄ , ZnSO ₄ , CuSO ₄ , MgSO ₄ (anhydrous), as thiosulfates Na ₂ S ₂ O ₃ , K ₂ S ₂ O ₃ , Mg S ₂ O ₃ , CaS ₂ O ₃ and as rhodanides KSCN, NaSCN, Mg (SCN) ₂ , Ca (SCN) ₂ , Zn (SCN) ₂ , Cd (SCN) ₂ , be used. From the salts

3 0 9 8-22 Λ1 1 3 9 B ^AD ORiGlNAt

Of the above-mentioned metals with organic acids, the salts of aliphatic mono- and dicarboxylic acids are particularly suitable, especially those with 2-10 carbon atoms, such as the salts of acetic acid, v / ie CH-COONa, Zn (CH ^ COO) ₉ , Cd (CH ^ COO) ₉ , Cu (CFUCOO) _P and others, such as propionic acid, butyric acid, maleic acid, fumaric acid, succinic acid, glutaric acid, tartaric acid, malic acid, etc. Of the salts of organic acids, zinc salts are particularly preferred.

Mixtures of the abovementioned catalysts can of course also be used. The use of these catalysts is problem-free, especially in Jonen cases in which the reaction products are worked up by distillation. However, even in those cases in which the reaction products crystallize out and are isolated by filtration, the removal of the catalysts does not present any difficulties.

The catalysts are generally used in amounts of 0 _? 1-5.0% by weight, preferably 0.5-3.0% by weight, based on the nitrile used. In some cases of high or low activity, these limits can also be exceeded or fallen below.

The reaction times depend entirely on the reactivity of the nitrile. Eoi the aromatic dinitriles, e.g. tere- and isophthalonitrile, the reaction times at the most favorable reaction temperatures are 4-12 hours, for most of the others Nitriles, some of which have higher reaction temperatures must be worked, the reaction times are between 8 and 24 hours.

In general, it is not necessary to use a solvent in this reaction. Only in a few cases ₉ in which solid nitriles are reacted with alkanolamines in a molar ratio of 1 ι 1.2-2.0, the amount of alkanolamine being insufficient to dissolve the nitrile, is the use of a solvent which is inert under the reaction conditions advantageous. Be-preferably weakly basic solvents at best be dimethylformamide has proved _$ but Dimeihy acetamide! ₉ NM-sthyl "

- 6 309822/1139. ^BATH ORIGINAL

- 6 pyrrolidone or pyridine are suitable.

The reactions are advantageously carried out under protective gas, to suppress weaving reactions and for better removal of the ammonia produced during the reaction.

Those which can be produced by the process according to the invention, for example Line oxazoline, bis-oxazoline, oxazine and bis-oxazine through special responsiveness, which gives them numerous Possible uses opened up. For example, they react with all compounds that contain reactive hydrogen own. The compounds can be used for the production of plastics, as stabilizers for plastics, as corrosion inhibitors and as intermediates for Pharmaceutlca.

The particular advantage of the method according to the invention consists in that with its help besides the simple α2-oxazolines and 4H-5,6-dihydrooxazines, especially bis-oxazolines and bis-oxazines can be obtained economically from cheap and technically easily accessible starting materials.

In addition to the method, protection is also claimed for the following new connections:

2- (m-Tolyl) - ^ 2-oxazoline
2 ~ Cyclohexen-3-yl- A 2-oxazoline
2-ethyl-4H-5,6-dihydro-1,3-oxazine.

The following examples explain the process according to the invention.

BATH ORIGINAL

- 7 -309822/1139

800 g of terephthalic acid dinitrile (TPDN) were introduced into 2383 g of monoethanolamine (MEAj ~ - 39 mol) with stirring. Then 12.6 g of zinc acetate (Zn (OCOCH,) «· 2H ₉ O) were added and the mixture was heated to 100 ° C. in a stream of nitrogen. After the main amount of TPDN had gone into solution, a further 864 g of TPDN were added, a total of 13 mol. The molar ratio TPDNtMKA was accordingly 1: 3. The amount of catalyst was 0.75 Gaw.?6, based on TPDN. After a short time, solution occurred with elimination of ammonia. Soon after, the reaction product began to precipitate. It was for 6 hours at 105 - 110 ⁰ C heated.

The reaction product was then present as a thick paste in the excess monoethanolamine. During the cooling , the mixture was diluted by stirring in about 1 liter of isopropanol, after which the reaction product could easily be filtered off. The crystal slurry was washed on the filter with isopropanol. The filter cake was then suspended in plenty of water with stirring, filtered and washed vigorously with water in order to remove the MEA quantitatively. This was followed by washing with acetone in order to remove most of the water and drying.

There were 2570 g of snow-white, coarsely crystalline p-phenylene-bis-. 2,2 '- (A2-oxazoline) obtained, which is a yield of 91.6 % of theory. corresponds, based on the TPDN used. The melting point of the product was 236-238 ° C (uncorr.). The product had sufficient purity for polymerizations and polyadditions.

C ₁₂ H ₁₂ N ₂ O ₂ ; Mol Wt: 216.23

Calc .: C: 66.65 %, H: 5.60 %; N: 12.96 %; 0: 14.79 %; Found: C: 66.48 %; H: 5.55 %; Nt 12.98 %; 0: 14.84 %.

BATH ORIGINAL

309822/1139

1025 g of terephthalic acid dinitrile (TPDN) (= 8 mol) were added to 1466 g of monoethanolarain (MEA) (= 24 mol) after adding 30.8 g of LiCl (= 3 % by weight), based on TPDN, and with stirring in a stream of nitrogen heated to 100 ^{° C.} The reaction was terminated after 12 hours.

A reaction product was obtained which was present as a thick slurry in excess MEA. While it was cooling down, the batch diluted with stirring in 500 ml of isopropanol, whereby an easy filterability was obtained * The filtered Crystal slurry was washed with isopropanol and then slurried in plenty of water with stirring, filtered again and with Washed vigorously with water to remove the MEA quantitatively. This was followed by slurrying in acetone, filtering and rewashing removed the water and dried.

1548 g of p-phenylene-bis-2,2 ^f - (£ .2-oxazoline) were obtained, which corresponded to a yield of 89.5 % of theory, based on the dinitrile. The melting point of the product was 236 - (uncorrected.) 238 ⁰ C. The product was of sufficient purity for polymerizations and polyadditions.

C ₁₂ H ₁₂ N ₂ O ₂ ; Mol Wt: 216.23

Calc .: C: 66.65 %; H: 5.60 %; N: 12.96% x 0: 14.79 %} Found: C: 66.48 %; H: 5.55 %, N: 12.98 %; Oi 14.84 %.

i (comparative example)

103.1 g of benzonitrile (= 1 mol) were stirred with 122 g of MEA (= 2 mol) for 8 hours under nitrogen at 130 ^° C. The reaction mixture was then worked up by vacuum distillation, with 2 fractions being collected. The first fraction, which passed between 68 and 119 ° C at 13 torr, contained mostly

- 9 309822/1139

BATH ORIGINAL

- y _

Starting material together with a little reaction product, while the second fraction boiling at 119 - passed over 122 ⁰ C at 13 Torr and slowly crystallized at room temperature, of pure 2-phenyl ~ A2-oxazoline was a gaschroraatcgraphisch determined content of 99.8 ^. . :

A conversion of 44% and a yield of 66 % of theory were calculated from the gas chromatographic analysis of the two fractions. The pure 2-phenyl-oxazoline had a melting point of 27-28 ° C, based on the reacted benzonitrile.

C ₉ H ₉ NO; Mol Wt: 147.17

Calc .: C: 73.45 ⁰ A; H: 6.16 %; ? N: 9 52% i Oi 10.87%; Found: C: 73.51 %; H: 6.25 % in Ns 9.50 %; Os 10.63 %,

As described in Example 3, benzonitrile and MEA were reacted under the same or slightly modified conditions, but "with the addition of 3 % by weight each (based on the nitrile feed) of a catalyst. The work-up was carried out as described in Example 3. In the table the results determined by gas chromatography are listed in comparison with Example 3. The effect of the catalysts is clearly evident therefrom.

- 10 -

BATH ORIGINAL

303822/1139

example
No. Reaction
Time
(H) Reaction
temperature
( ⁰ G) catalyst sales
{%) yield
(%) 3 8th 130 - 44 66 4th 4th 130 LiCl 93 88 5 6th 130 LiCl 100 81 6th 12th 110 LiCl 97 84 7th 24 100 LiCl 99 85 8th 12th 120 LiBr 97 83 9 8th 130 KSCN 97 81 10 ' 8th 130 NaBr 84 65 11 8th 130 Na acetate 91 73 12th 12th 110 Zn acetate 100 87 13th 8th 130 Cd acetate 100 84 14th 8th . 130 Cu acetate 100

103.1 g of benzonitrile (= 1 mol) were heated with 150 g of 1,3-propanolamine (= 2 mol) with the addition of 3% by weight of LiCl while stirring in a stream of nitrogen at 130 ^° C. for 12 hours.

- 11 -

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The reaction product was then worked up by vacuum distillation. It was, a lead with the Kp ₁ = 51 - 99 ° C 177.4 g of a fraction with the Kp = ₁ 99.0 - 99.5 ° C obtained. It is 2-phenyl ~ 4H-5,6-dihydro ~ 1,3-oxazine with a purity of 99.5 °, determined by gas chromatography. The refractive index was ng ⁰ = 1.5665.

Gas chromatographic analysis of the first runnings showed a conversion of 97.5 % of benzonitrile; the yield was accordingly 74.7 % of theory.

₁₀₁₁ Mol Wt: 161.20

Calc .: C: 74.50 #; H: 6.88 %; N: 8.69 %; 0: 9.93 %; Found: C: 74.42 #; H: 6.75 %> N: 8.65 %} 0: 9.82 %.

58.6 g (= 0.5 mol) of o-tolunitrile ^{were heated to 130 °} C. for 8 hours in a stream of nitrogen with 61.6 g of MEA with the addition of 3% by weight of LiCl while stirring.

The work-up was done by vacuum distillation. After a forerun with bp ₁ = 38-90 ° C., 20.5 g of a fraction with bp ₁ = 90.0-91.5 ° C. passed over. It is 2- (o-Talyl) -A2-oxazoline with a gas chromatographic purity of 98.2 %,

Gas chromatographic analysis of the first runnings showed a conversion of 42.0 %; the yield of o-tolyl-oxazoline was 60.5 % of theory

20th

The refractive index n ^ was determined to be 1.5647.

₁₀₁₁ Mol Wt: 161.20

Calc .: C: 74.50 $$; H: 6.88%; N: 8.69 % t 0: 9.93 %; Found: C: 74.54 %; H: 6.73 %; N: 8.76 %; 0: 9.90 %.

- 12 309822/1139

As indicated in Example 16, m-tolunitrile was reacted with MEA.

The distillation of the reaction product gave a forerun with Kp = ₁ 45-95 ⁰ C and 43.8 g of a main fraction with Kp = ₁ 95.0 to 95.5 ⁰ C is 2 ~ (m-tolyl) -A2- oxazoline with a gas chromatographic purity of 99.8 %. The refractive index was n ^ = 1.5610.

The gas chromatographic analysis of the first runnings showed a conversion of 86.0 % of m-tolunitrile, the yield was accordingly 64.7 % of theory.

₁₀₁₁ Mol Wt: 161.20

Calc .: C: 74.50 %; H: 6.88 %; N: 8.69 %; 0: 9.93 %; Found: C: 74.46 %; H: 6.81 %; N: 8.63%; 0: 9.92 %.

As indicated in Example 16, p-Tolunitrile was reacted with MEA.

. The distillation of the reaction product gave a forerun with the Kp ™ ₂₀ = 80-145 ⁰ C and 60.9 g of a main fraction with the ₂₀ Kp = 145 to 145.5 ° C It is 2- (p-tolyl) -a2-oxazoline with a purity of 99.9 % by gas chromatography - the crystalline product had a melting point of 72-73 ° C. (uncorr.).

Gas chromatographic analysis of the first runnings showed a conversion of 91.5 % of p-tolylnitrile; the yield was accordingly 82.6 % of theory.

₁₀₁₁ Mol Wt: 161.20

Calc .: C: 74.50 %; H: 6.88 %; N: 8.69 %; Oj 9.93 %; Found: C: 74.53 %; H: 6.80 %; N: 8.68 %; 0: 9.85 %.

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309822/1139

107.2 g (= 1 mol) of 3-tetrahydrobenzonitrile were obtained as 122.2 g (= 2 mol) MEA with the addition of 3 wt., # KSCN with stirring in Heated to 140 ° C. in a nitrogen atmosphere for 24 hours.

The work-up was done by vacuum distillation. After a forerun with Kp = ₁₇ 72-108 ⁰ C were 59 3 g of a fraction having the Kp _1, -? = 18O ⁰ C. It is 2-cyclohexen-3-yl-42-oxazoline with a gas chromatographic purity of 99 »4 %, The

20 *

Refractive index was n ^ = 1.4986.

According to the gas chromatographic analysis, a conversion of 88.7 % was calculated, the yield was accordingly 44.2 % of theory.

C ₉ H ₁₃ NO; Mol Wt: 151.20

Calc .: C: 71.49 ⁰ M H: 8.66%; N: 9.27 %; 0: 10.58 %; Gef _e : C, 71.40 56; H: 8.75 %; N: 9.35%; 0: 10.40 #,

54.1 g adiponitrile (= 0.5 mole) were heated with 91.6 g of MEA with the addition of 1.62 g zinc acetate (= 3 Gew.SO with stirring in a nitrogen stream 12 hours 105 ⁰ C "

Thereafter the product was distilled in vacuo, -said after a forerun with Kp = ₁ 44-113 ⁰ C 76.2 g of the main fraction with bp ₁ = 113-129 ° C passed over. Gas chromatographic analysis of this fraction indicated a 100 % conversion. The product consisted of 17.0 g of 2- (4-cyanobutyl) -42-oxazoline (= 22.3 # d.Th). Because the tetramethylene-bis-oxazoline out of the mixture

- 14 -

303822/1139

Was crystallized, it could easily be separated from the liquid Üyanbutyl-oxazoline and recovered in pure form. It had a melting point of 53 - 54 ° C; Bp ₁ = 128 ° C.

^C 10 ^H 16 ^N 2 ° 2 ^{; Mol} - ^{weight *:} 196.24

At- .: C: 61.20 %; H: 8.22 %; N: 14.28 %; Οι 16.31 Gex.i Ci 61.08 tf; H: 8.25 % \ N: 14.22 %; 0; 16.24

82.2 g of acetonitrile (= 2 mol) were refluxed with 244.4 g of MEA (= 4 mol) with the addition of 2.5% by weight of zinc acetate with stirring in a nitrogen atmosphere for 12 hours, the reflux temperature gradually increasing from 98 ⁰ C to 120 ⁰ C rise "the gas chromatographic analysis of the reaction product showed a conversion of 94.5% and a yield of 144.5 g = 90.4% of theory to 2-methyl-z> 2-oxazoline,

The methyl oxazoline could easily be obtained in pure form by distillation at normal pressure. A gas chromatographically 99.8% product showed a Κρ ₇ ρ · _ς = ^{110-111 0} C, its refractive index was n ^ = 1.4340.

C ^ H ₇ NOj mol wt: 85.10

Calculated: C: 56.45 %; H: 8.29 %} N: 16.46 % i 0: 18.80 %; Gef.i C: 56.49 ⁰ A; H: 8.20 %; Ni 16.36 %; Ot 18.72 %.

- 15 -309822/1139

22:

1102 g of proplonitrile (= 2 mol) were heated to reflux temperature for 24 hours with 244.4 g of MEA (= 4 mol) with the addition of 3% by weight of LiCl while stirring in a stream of nitrogen. This rose from 103 ° C to 129 ° C with increasing reaction time. Gas chromatographic analysis of the reaction product showed a conversion of 97.1 % and a yield of 140 g = 72.7 % of theory. to 2 ~ ethyl-A2-oxazoline.

The ethyl oxazoline could easily by distillation at normal pressure can be kept pure. A gas chromatography 99.0% iges

Product had a bp ₇ . _p = 127.5-128 ° C. The refractive index on / MO

was η £ ^υ = 1.4371 ..

C ₅ II ₉ NO; Mol Wt: 99.13

Calc .: C: 60.58 %; H: 9.15 %; N: 14.13 %; O: 16.14 %; Found: C: 60.67 %; H: 9.26 %; N: 14.07 %, 0: 16.00 %.

58.6 g of p-tolimitrile (= 0.5 mol) were mixed with 75.1 g of 1,3-propanolamine (= 1 mol) with the addition of 2.5% by weight of LiCl while stirring in a stream of nitrogen at 130 ^° C. for 12 hours heated.

The work-up was done by vacuum distillation. After a forerun with the Kp ,, = 53-113 ⁰ C were 69.3 g of a fraction with the Kp ₁ = 113 ° C. It is 2- (p-Tolyl) -4H ~ 5,6-dihydro-1,3-oxazine with a gas chromatographic purity of 98.3 %,

From gascliromatographisehen analysis, a yield of 82.9% was found at a conversion of 95.4% of theory The product had a melting point of 45-47 ° C. (uncorr.).

₁₁₁₃ Mol Wt: 175.22

Calc .: C: 75.40 % -, H: 7.48 %; N: 7.99 %; 0: 9.13 %; Found: C: 75.48 %; H: 7.53 %; N: 8.02 %; 0: 9.00 %.

- 16 309822/1139

Example 24:

_mm ^ _m ^ _- , _mm -km WM! ■ »IHt * ·« HH OT

^{58.6 g in tolunitrile (-0.5 mol) were heated to 130 °} C. for 12 hours with 75.1 g of 1.3 propanolamine (= 1 mol) with the addition of 3% by weight of LiCl while stirring in a stream of nitrogen.

The work-up was done by vacuum distillation. After a forerun with Kp = ₁ 48-112 ⁰ C were 70.4 g of a fraction with the Kp ₁ = 112 ° C. It is 2 ~ (ra-TolyJL) -4H-5,6-dihydro-1,3-oxazine with a gas chromatographic purity of 99 »5 %.

The gas chromatographic analysis showed a conversion

»Of 95.4 % a yield of 84.2 % of theory The product was liquid at room temperature and had a refractive index of nQ = 1.5580.

₁₁₁₃ Mol Wt: 175.22

Calc .: C: 75.40 %; H: 7.48 %; N: 7.99 %, 0: 9.13 %; Found: C: 75.36 %; H: 7.42 %; N: 7.99 ^ J 0: 9.10 %.

75.8 g of 4-chlorobenzyl cyanide (= 0.5 mol) were heated with 61.0 g of MA (= 1 mol) with the addition of 3 % by weight of LiCl with stirring in a stream of nitrogen at 100 ^° C. for 12 hours.

The work-up was done by vacuum distillation. After a forerun with Kp = ₁ 62-120 ⁰ C were 66.6 g of a fraction with ₁ Kp = 120 ⁰ C. It is 2 ~ (4-chlorobenzyl) -a2-oxazoline with a gas chromatographic purity of 98.9 ^. The product showed a freezing point of +11 ⁰ C,

From gas chromatography analysis, a yield of 71.5% was found at a conversion of 95.1% of theory -

C ₁₀ H ₁₀ ClNOj Mol Wt: 195.65

Calculated: C: 61.39 %; H: 5.15 %, "N: 7.16 %; 0: 8.18 %; Cl: 18.12 %; Found: C: 61.18 %; H: 5.25 %; N: 7 , 05 %; 0: 8.07 %; Cl: 18.00 %.

- 17 ■ 509822/1139

52.1 g of 3-cyano-pyridine (= 0.5 mol) were heated with 61.1 g of MEA (= 1 mol) with addition of 5% by weight of LiCl while stirring in a nitrogen stream at 100 ^° C. for 12 hours.

It was then worked up by vacuum distillation. Wax a lead with the Kp = ₂ 45-95 ⁰ C were 53 "5 g of a fraction with the Kp = ₂ 95-96 ⁰ C over. It was 2 ~ (3-pyridyl) -42-oxazoline of melting point 69-71 ⁰ C. ·

Gas chromatographic analysis gave a conversion of 95.6% at a yield of 75.5% of theory

C ₈ H ₈ N ₂ O; Mol Wt: 148.17

Calc .: C: 64.84 %; H: 5.45 % i N: 18.91 % i Os 10.80 %; Found: C: 64.80 %; H: 5.51 %; N: 18.88 %; 0: 10.75%

Propionitrile 55.1 g (= 1MoI) were heated with 150.2 g of 1,3-propanolamine (= 2 mol) with addition of 2 wt% _o zinc acetate with stirring in a nitrogen stream reflux for 24 hours, the reflux temperature gradually from 106 ⁰ C rose to 124 ⁰ C.

In the vacuum distillation were 93.1 g of 2-Ä'thyl-4H-5,6-dihydro-1,3-oxazine having the boiling point Kp _10Q = 78-80 ⁰ C. "

Gas chromatographic analysis showed that the product had a purity of 99.4, that the conversion was 100 % and the yield

18 -

309822/1139

of ethyl oxazine 82.2 % of theory fraud. The refractive index of the product was determined to be ng = 1.4520.

₆₁₁ j mol wt: 113.16

Boron .: C: 63.68 %; Ks 9.80 %; N: 12.38 %; 0: 14.14 %; Gel .: C: 63.72 tf; H: 9.75 %; N: 12.33 ⁰ M 0: 14.10%

The yields of the examples show that the catalysts according to the present invention have far better catalytic effects than those described in U.S. Patent 2,402,898.

- 19 -

309822/1139

Claims (2)

Claims Λu Process for the preparation of cyclic imidic acid esters of the general formula R " (CR ¹ R ") in the η 1 or 2, R is an aliphatic, cycloaliphatic, araliphatic heterocyclic, aromatic or ■ 0 £ CR ^! R ») - rest R " and R 'and R "are identical or different radicals from the group consisting of hydrogen, alkyl, aryl, aralkyl, cycloalkyl, OH, COOH, CN or halogen, by reacting mono- or dinitriles with optionally C-substituted Cp- or C- - Aminoalkanols, characterized in that the reaction is carried out in the presence of salts of inorganic and / or organic acids of metals of the 1st and 2nd main and subgroups of the periodic table as catalysts. 2. The method according to claim 1, characterized in that the nitriles are reacted with the aminoalkanols with one another in such amounts that 1-3 moles of aminoalkanol, preferably 1.2-2.2 moles, come per mole of cyano group. - 20 - 309822/1139 Process according to Claim 1 or 2, characterized in that the reaction is carried out in a temperature ^
performs. Temperature range of 15 - 180 ^0C, preferably 90 - 15O ⁰ C, Method according to claims 1-3 »characterized in that that the reaction is carried out in an inert solvent. Process according to Claim 4, characterized in that the inert solvent is weak basic solvents are used. 6. Process according to claims 1-5 »characterized in that the catalysts are used in amounts of 0.1-5.0 % by weight, preferably 0.5-3.0% by weight« 7 « Process according to claims 1-6, characterized in that the salts used are zinc salts of mono- and / or dicarboxylic acids having 2-10 carbon atoms. 8 _{y <} Process according to Claims 1-6, characterized in that the salts of organic acids used are acetates. 2yy. Method according to claims 1-6, characterized that one uses Alkalirhcdanide as salts of inorganic acids. 10. Process according to claims 1-6, characterized in that the salts of inorganic acids used are lithium halides. - 21 - 11. 2-m- (Tolyl) -A2-oxazole ± n 12 _P 2-cyclohexen-3-yl-A2-oxazoline 13. 2-Ethyl-4H-5,6-dihydro-1,3-oxazine dr.kn.-ba 309822/1139