JPS5820953B2 - Chloro-oxygen fluoride - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing cycloalkanone oximes or salts thereof.

For purposes of illustration, the invention will be described primarily with respect to cyclododecanone oxime, but is in no way limited to the preparation of said compounds.

Cyclododecanone oxime can be used as a precursor to laurolactam, a precursor to nylon-12 and its copolymers, and various methods for its preparation are described in the literature.

According to one of the methods, the cyclododecatriene, cyclododecadiene or cyclododecene used as starting material is reacted with nitrosyl chloride.

From French Patent Specification No. 1 361 872, the reaction of cyclodecatriene with nitrosyl chloride in the presence of acetic acid yields bis(l-nitrone-2-chlorocyclododecadiene), which is then converted into 2-chloro-cyclo It is known that dodecagenone oxime is isomerized.

Alternatively, similar chloro-oxime compounds can be obtained in a single step by reaction of cyclododecatriene with nitrosyl chloride and hydrogen chloride (see GB 947,396).

Furthermore, it is known to prepare 2-chlorocyclododecanone oxime by reacting nitrosyl sulfuric acid with cyclododecene in the presence of hydrogen chloride (FR 1 361 903).

To produce cyclododecanone oxime, selective hydrogenation of 2-chlorocyclododecanone oxime or 2-chlorocyclododecanone oxime is conveniently carried out in the presence of hydrogen and a palladium catalyst (German Published Specification No. No. 1205089).

Said compound can then be converted to laurolactam by conventional Beckmann rearrangement.

The main drawback of the production of cyclododecanone oxime from cyclododecatriene via 2-chlorocyclododecagenone oxime lies in the instability of the palladium catalyst during the hydrogenation/hydrodechlorination step, which This causes a decrease in the hydrogenation activity of the two carbon-carbon double bonds present in .

This requires post-hydrogenation and is not desirable as an industrial process.

In addition, a significant amount of reaction heat must be dissipated in the hydrogenation/hydrodechlorination step while the palladium catalyst has not yet lost activity.

This is inconvenient from an equipment standpoint, leading to deposition of carbonaceous material on the catalyst and greater loss of catalyst activity.

The stability of catalysts for hydrodechlorination reactions depends on the unsaturated 2-
Saturated 2 instead of chloro-cyclododecagenone oxime
-Chloro-cyclododecanone oxime will be affected to a lesser extent when it is the starting compound.

This means that the catalyst consumed from a hydrogenation run with the saturated chloro-oxime described above as the feedstock was 1.4.6% W in a comparable run with the unsaturated chloro-oxime described above.
This is demonstrated by the fact that it gave a loss in ignition of only 8.6% W compared to the loss of .

The use of 2-chlorocyclododecanone oxime is also advantageous in that less heat of hydrogenation needs to be dissipated.

The use of cyclododecene as a starting material thus has several advantages.

The use of cyclododecene is particularly attractive in large-scale production, since mixtures of cis- and trans-cyclododecenes can be readily prepared from cyclododecatriene by selective hydrogenation over suitable catalysts.6 On the other hand, the use of 2-chlorocyclododecene The production of non-oximes starts from cyclododecene, but only trans-cyclododecene reacts with nitrosyl chloride, thus leaving unreacted cis-cyclododecene.
It has the disadvantage of leaving behind substantial amounts of isomers.

However, the latter isomer is always present in the reaction mixture obtained by hydrogenation of cyclododecatriene.

Thus, complete conversion of cyclododecene in the chloro-oximation step is not possible, and the remaining cis-cyclododecene can be converted into cyclododecanone oxime (in the subsequent hydrodechlorination step in the presence of palladium/hydrogen). may simply be hydrogenated to cyclododecane because of the nature of the process and because separation of unreacted cis-cyclododecene from the chloro-oxime product prior to the hydrodechlorination step is not economically attractive. .

Generally, if in the first step the starting olefin(s)
Alkanes will also be formed during the hydrodechlorination step if 100% conversion of 100% is not achievable or desired.

It is noted that usually an excess of nitrosyl chloride is used in the chloro-oximation step if possible to achieve quantitative conversion of the starting olefin.

However, the selectivity (ie selectivity) of the reaction will be reduced due to the reaction of the nitrosyl chloride with the chloro-oxime giving undesirable by-products.

The use of sulfurized noble metal catalysts now substantially prevents undesired hydrogenation of unsaturated reactant compounds, such as cis-cyclotothycene, and at the same time stabilizes the highly favorable catalytic activity for hydrodechlorination reactions. It has been found that it can be maintained in operation.

Therefore, the present invention provides a method for producing a cycloalkanone oxime or a salt thereof by hydrogenating a 2-chlorocycloalkanone oxime or a salt thereof in the presence of a catalyst, in which the amount of sulfur is from 1 to 100 based on the weight of the oxime or oxime solvent
The method is characterized in that it is carried out in the range up to ppm.

The use of palladium sulfide catalysts in the process according to the invention particularly reduces the formation of saturated hydrocarbons, while the catalyst retains a sufficient degree of selective activity for the hydrodechlorination of 2-chloro-oximes. reduced to a considerable level.

The hydrogenation according to the invention can be carried out in the liquid phase.

It can be carried out in a batchwise or (semi-)continuous manner.

The advantage of the process according to the invention is that the unsaturated starting compounds are substantially protected against hydrogenation and can be easily separated from the reaction products in any convenient step, for example during work-up and purification measures. be.

Therefore, the cis-cyclododecene that is still present, together with the trans-cyclododecene that was initially present or formed by the isomerization of the cis-cyclododecene during the hydrodechlorination step, is added to the chloro-oximation of the cyclododecene and the subsequent hydrogenation. It can be easily separated from the product cyclododecanone oxime obtained by chemical dechlorination.

The cyclododecene (mixture) obtained can be recycled to the chloro-oximation step, preferably via an isomerization reactor in order to increase the amount of trans-cyclododecene.

The isomerization conditions can easily be selected in a range such that, if desired, a substantial amount of trans-cyclododecene is obtained up to a cis-trans equilibrium composition (cis:trans ratio of 1:2).

For example, during the hydrodechlorination of 2-chloro-cyclododecanone oxime to cyclododecanone oxime with the aid of a palladium sulfide catalyst, when a small amount of sulfur, on the order of 5 ppm, is present in the catalyst, at the same time in the reaction mixture. 59 such that the cis-cyclododecene present in is comparable to the equilibrium composition.
% and high conversions of 2-chloro-cyclododecanone oxime were found to be substantially retained.

This effect is found to be gradually reduced when large amounts of sulfur are used in the catalyst.

However, although isomerization also occurs in the absence of sulfur, the presence of sulfur in the noble metal catalyst suppresses undesired hydrogenation of cyclo-dodecene.

The process according to the invention is advantageous in that quantitative conversion of the starting (cyclo)alkene is no longer required.

The amount of (unstable) by-products from the chloro-oximation step and the amount of (cyclo)alkanes formed by hydrogenation of unconverted starting material are thus also substantially reduced as previously mentioned.

The palladium sulfide catalyst according to the invention is preferably used supported on a carrier, but may also be used unsupported depending on the type of hydrodechlorination reactor used.

Suitable supports include any support that is inert under the reaction conditions, such as, for example, alumina, silica, silica-alumina, soria (thorium oxide), barium sulfate, carbon and others.

Alumina is the preferred carrier. Palladium may suitably be used in an amount ranging from 0.1 to 5% W, calculated as metal on the support.

A weight range of 0.2 to 2% is preferred. Very good results were obtained using a palladium on sulphide alumina catalyst containing 0.5% W palladium calculated as metal on the support.

Examples of sulfurizing agents that can be used are hydrogen sulfide, mercaptans, dialkyl sulfides, elemental sulfur and tetrahydrothiophene.

Preference is given to using tetrahydrothiophene as sulfiding agent.

Palladium catalysts can be sulfided by any suitable technique.

Sulfiding agents are advantageously used by introducing them into the feed to the hydrodechlorination reactor, preferably dissolved in the reaction mixture.

It is also possible to sulfurize the supported noble metal catalyst before use, for example by impregnating the catalyst with a suitable amount of a sulfiding agent dissolved in a hydrocarbon.

If a pre-sulfided catalyst is used, it is recommended that the feedstock contain a sulfiding agent at about 0.degree. C. to maintain the amount of sulfur in the catalyst at the desired level.

It has been found that the optimum protection effect is obtained when very small amounts of sulfiding agent are added to the feedstock.

It is chosen to use an amount of sulfur in the range of 100 ppm to 100 ppm, calculated as sulfur based on the weight of the feedstock.

The term "Pa feedstock" used herein simply means chlorooxime + solvent.

The use of sulfur in amounts below 1 ppm insufficiently suppresses the hydrogenation of unconverted starting materials such as cis-cyclododecene.

1100pp calculated as sulfur based on feedstock
Sulfur in amounts up to is preferably used.

Amounts of sulfur much in excess of the latter amount lower the hydrodechlorination rate.

2 to 75 p calculated as sulfur based on feedstock
Best results are obtained using sulfur amounts ranging up to pm, with amounts of 55-50 ppm being preferred.

Olefinically unsaturated compounds can be used as starting materials for the production of 2-chloro-cycloalkanone oximes, which are converted into cycloalkanone oximes by the process according to the invention.

Suitable compounds are cyclic alkenes, cyclic alkadienes, cyclic alkatrienes, polycyclic alkenes and others.

The compounds can contain any substituents that are inert under the reaction conditions, such as alkyl, aryl
l), alkaryl, and/or aralkyl groups.

Particular preference is given to cyclic olefins containing up to 3 double bonds.

Suitable cyclic alkenes are, for example, cyclohexene, cycloheptene, cyclooctene, cyclodecene, cyclododecene, and cyclotetradecene, with cyclododecene being most preferred.

Suitable cyclic alkadienes and cyclic alkatrienes include cyclodecadienes, cyclooctadiene-1
-5, cyclododecadienes and cyclododecatriene-1, 5, and 9.

Cyclododecatriene is preferred. Suitable methods for the chlorooximation of olefinically unsaturated compounds are described in the literature, for example in the patent specifications mentioned above.

The 2-chloro-oximes obtained by the chloro-oximation of the cyclic olefins described above can be converted to the corresponding oximes by the hydrodechlorination reaction according to the invention.

The use of 2-chlorocyclododecanone oxime as starting material for the production of cyclododecanone oxime is chosen.

2 for the production of the corresponding cycloalkanone oximes
It is also possible to start with salts of -chloro-cycloalkanone oximes.

Such salts, such as the chloride or sulfate of the 2-chloro-cycloalkanone oxime, can be prepared from the reaction of the appropriate cycloolefin with nitrosyl chloride in the presence of hydrochloric acid or with nitrosyl sulfate/hydrochloric acid, respectively. It will be easily obtained.

The salts are converted to free oximes (fre) prior to hydrodechlorination.
eoximes), but can also be suitably reacted as salts.

In order to obtain corresponding salts that can be suitably hydrodechlorinated,
It is also possible to treat the 2-chloro-oxime solution with a suitable acid, such as hydrochloric acid or sulfuric acid.

Although the hydrodechlorination reaction can be carried out in the absence of a solvent,
Preferably it is carried out in the presence of a solvent; solvents include alcohols, ethers, acids, esters, hydrocarbons, unsaturated hydrocarbons and chlorinated hydrocarbons such as hiscochloromethane, chloroform, dichloroethane, etc. Hydrocarbons can be used.

Aromatic solvents such as benzene, toluene or xylene can also be used.

Dichloromethane has proven to be an excellent solvent.

The amount of solvent used is by no means critical.

Usually a large excess of solvent is used with respect to the 2-chloro-oxime to be hydrodechlorinated, for example a 10- to 100-fold excess.

However, it is of course also possible to use amounts of solvent outside the ranges mentioned.

The hydrogenation reaction can be carried out at pressures from atmospheric to 50 atmospheres.

Pressures in the range from 10 to 35 atmospheres were selected, with approx.
A pressure of 0 atmospheres is very suitable.

The hydrogenation reaction may be carried out in the presence of an inert gas such as helium, argon, nitrogen, etc.

The reaction is generally carried out at a temperature ranging from 0°C to 150°C, with temperatures ranging from 15°C to 90°C being preferred.

The invention is illustrated by the following examples and references, which do not limit the scope of the invention in any way.

Example 1 (Reference Example) The hydrodechlorination of 2-chlorocyclododecanone oxime was carried out in a continuous-floratricle-reciprocal manner.
us -f low trickle -phase
reactor) on 0.5% W palladium on an alumina support calculated as metal on support.

The feedstock was a 2.5% W solution of 2-chlorocyclododecanone oxime in dichloromethane.

It also contained cis-cyclododecene, but cis-
Cyclododecene is a commercial mixture that also contains 8% trans-cyclododecene and the balance is cyclododecane.
Formed 7%.

The molar ratio to chloro-oxime in the raw material of the mixture is 0.
．． It was 5.

The liquid hourly space velocity was 4tCtcatalyst)-1h-1.

The reaction was carried out at 65° C. and a total pressure of 20 atmospheres.

The analysis was carried out by venting-liquid chromatography (G
LC) and potentiometric titration, 95% W of the 2-chlorocyclododecanone oxime uptake was almost quantitatively converted to cyclododecanone oxime and 59% m of the cyclododecene uptake was hydrogenated to cyclododecane. It was shown that

This experiment clearly shows that the use of unsulfurized palladium catalyst results in undesired amounts of cyclododecane production.

Example ■ (Example) The hydrodechlorination of 2-chlorocyclododecanone oxime was carried out in such a way that the reaction temperature was 60°C and 5 ppm sulfur, calculated as sulfur based on the feedstock, contained the appropriate amount of tetrahydrothiophene. It was carried out as described in Example 1, except that it was introduced into the feedstock solution by addition.

Stable operation for 80 hours was achieved.

Experimental data showed 85% conversion of 2-chloro-cyclododecanone oxime after a considerable amount of time, while only 7% m-cyclododecane was hydrogenated to cyclododecane.

This experimental data shows that not only was the undesirable hydrogenation of cyclododecene substantially suppressed by using the sulfided catalyst, but the conversion of 2-chlorocyclododecanone oxime remained high and, moreover, the conversion of cis-cyclododecene It was also shown that a substantial amount was converted to trans-cyclododecene.

Example 1 Hydrodechlorination of 2-chlorocyclododecanone oxime was carried out as described in Example 2, except that a reaction temperature of 85°C was used.

Under these conditions 95% of the 2-chlorocyclododecanone oxime was converted and 11% of the cyclododecene was converted.
was hydrogenated to cyclododecane.

Example ■ (Example) The effect of sulfur content on hydrodechlorination was determined by conducting the experiment as described in Example ■, except that -10 ppm sulfur was used, calculated as sulfur based on the feedstock. determined by.

The experimental results show that 7 of 2-chlorocyclododecanone oxime
9% conversion was achieved, indicating that only 3% of the cyclododecene was hydrogenated to cyclododecane.

Example ■ Hydrodechlorination of 2-chlorocyclododecanone oxime was carried out as described in Example ■, except that the feedstock contained 50 ppm sulfur, calculated as sulfur based on the feedstock. .

Conversion rate of 2-chlorocyclododecanone oxime is 76%
, and simply 0. of cyclododecene.
Only 5% m was hydrogenated to cyclododecane.

Example (1) The experiment described in Example (2) was repeated at a reaction temperature of 85°C.

The conversion rate of 2-chloro-cyclododecanone oxime is 95
%, and 1.5 of cyclododecene
%m was hydrogenated to cyclododecane.

Claims (1)

[Claims] A method for producing a cycloalkanone oxime or a salt thereof by hydrogenating a 12-chlorocycloalkanone oxime or a salt thereof in the presence of a catalyst, in which the amount of sulfur is reduced to oxime or oxime+ in the presence of a palladium sulfide catalyst.
1 to 100 ppm based on the weight of the solvent.