Organic compounds -- part of the class 532-570 series – Organic compounds – Amino nitrogen containing
Reexamination Certificate
2002-11-14
2003-12-16
O'Sullivan, Peter (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Amino nitrogen containing
C564S265000, C564S269000
Reexamination Certificate
active
06664423
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a process for preparing an oxime from a ketone or an aldehyde.
2. Discussion of the Background
European patent application EP-A-0 267 362 mentions, in examples 8 and 9, the two-phase preparation of cyclohexanone oxime. Toluene is used as solvent, but has the disadvantage that it is not inert toward concentrated sulfuric acid. This is of critical importance, since, in the case of high-boiling oximes, for example cyclododecanone oxime, the oxime present after the reaction is extracted from a solvent with sulfuric acid. When toluene is used as ammoximation solvent, solvent exchange must first take place, since toluene is not inert toward sulfuric acid. This means an additional process step. In addition, in EP-A-0 267 362, a yield of only <90% is achieved in the two-phase system in example 8. High reaction rates, however, are very important for industrial use in the case of larger rings, for example cyclododecanone, since with increasing molecular weight, the unreacted ketone may only be separated off from the corresponding oxime with great technical complexity. In EP-A-0 267 362, example 9, the ternary solvent mixture toluene, tert-butanol and water is used to prepare cyclohexanone oxime. This ternary solvent mixture has the disadvantage that the oxime present after the reaction is distributed among the two phases and thus complete removal of the oxime by phase separation is not possible. Furthermore, the conversion rates achieved in EP-A 0 267 362, examples 8 and 9, at 1.1 g of oximeg of catalyst-h are low. No example is disclosed of two-phase ammoximation of cyclododecanone.
Eni-Chem, in German laid-open application DE 195 21 011 A1 (equivalent to U.S. Pat. No. 5 498 793) claims a process for ammoximating acetophenone and cyclododecanone. The publication also claims the use of C
5
-C
8
aliphatic hydrocarbons as solvent, without disclosing an example of such a reaction.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a process for the ammoximation of ketones and aldehydes. In particular, relatively large and bulky ketones such as acetophenone and cyclododecanone should be used as starting materials. The product should be removed completely via phase separation. The conversion at a peroxide yield of >50% should be as complete as possible. The conversion rate should be in an industrially acceptable range and the solvent used should be inert toward sulfuric acid. The conversion should be, if possible, so high that subsequent reaction with an aqueous hydroxylamine solution, as described by Eni-Chem in European patent application EP-A-0 564 040 for the example of cyclohexanone can be omitted.
This and other objects have been achieved by the present invention the first embodiment which includes a process for preparing an oxime, comprising:
reacting a ketone or an aldehyde with hydrogen peroxide and ammonia in a system of one aqueous phase and one phase consisting of a hydrocarbon inert under the reaction conditions, in the presence of a catalyst system which comprises at least two components; and
wherein a first component of the catalyst system is present in heterogeneous form and is based on titanium, silicon and oxygen; and
wherein a second component is a homogeneously dissolved or suspended ammonium salt; and
wherein at least one interphase contactor is present.
DETAILED DESCRIPTION OF THE INVENTION
Surprisingly, it has now been found that ketones and aldehydes can be ammoximated in the presence of hydrocarbons inert under the reaction conditions. A high conversion rate and peroxide yield is achieved in the presence of a titanium silicalite as heterogeneous catalyst if ammonium salts are added as homogeneous or suspended cocatalyst and one or more interphase contactors are added.
The present invention therefore relates to a process for preparing oximes by reacting ketones or aldehydes with hydrogen peroxide and ammonia in a system of two liquid phases. One phase is an aqueous system and the other phase contains at least one hydrocarbon inert under the reaction conditions. The reaction proceeds in the presence of a catalyst system which consists of at least two components. One component is based on titanium, silicon and oxygen, preferably in the form of a titanium silicalite. The second component is an ammonium salt which is preferably in homogeneous dissolved form or, at high concentrations, is also in part suspended. One or more surfactants or a mixture of one or more surfactants and one or more phase-transfer catalysts are also present as interphase contactors. For practical reasons, the number of interphase contactor components is in each case at most 3, preferably 1.
The catalyst is based on titanium, silicon and oxygen. The catalyst is preferably a titanium silicalite which is commercially available, for example, as titanium silicalite TS1.
The catalyst can be used as solid, not only crystalline as powder, but also as shaped body. If the catalyst is used as shaped body, at least one further component consisting of an acidic solid which contains an inorganic or organic support material can also be present in addition to the titanium/silicon/oxygen component. Either the support material itself has Lewis acid or Brönsted acid properties, or corresponding Lewis acid or Brönsted acid functional groups are applied to the support material and such groups are introduced physically or chemically. The support material can at the same time also act as binder of the shaped body. A preferred support material is, for example, an acidic inorganic solid based on aluminum oxide or aluminosilicate. However, the support material can alternatively be an organic solid based on acid or strongly acid ion exchangers.
The weight ratio of catalyst to support material, if used, is preferably from 0.1:1 to 10:1. The weight ratio of catalyst to support material includes all values and subvalues therebetween, especially including 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1, 8:1, 8.5:1, 9:1 and 9.5:1.
The catalyst is used in amounts of 0.2-5% by weight, based on the weight of total reaction solution. The amount of catalyst includes all values and subvalues therebetween, especially including 0.5, 1, 1.5, 2. 2.5, 3, 3.5, 4 and 4.5% by weight.
The catalyst can also be disposed in the form of a fixed bed (fixed-bed catalyst) through which the reaction mixture is passed. The residence time in the fixed bed is preferably from 0.1 to 120 seconds, particularly preferably from 0.5 to 60 seconds. The residence time includes all values and subvalues therebetween, especially including 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 and 110 seconds.
As homogeneous cocatalyst for the inventive process, all ammonium salts can be used which are sufficiently soluble in the reaction mixture and whose anions do not have a disadvantageous effect on the course of the reaction. Non-limiting examples are ammonium salts of strong mineral acids, for example ammonium chloride, ammonium sulfate or ammonium nitrate, and ammonium salts of carboxylic acids, for example ammonium formate, acetate, propionate, oxalate, glutarate, citrate or benzoate. The amount of ammonium salt can be chosen within broad limits. Preferably, the ammonium salt is used at a concentration of from 0.001 moukg to 1 mol/kg. The amount of ammonium salt includes all values and subvalues therebetween, especially including 0.005, 0.01, 0.05, 0.1 and 0.5 mol/kg. The ammonium salt is preferably added either directly to the reaction mixture or to the hydrogen peroxide used in the reaction.
In a preferred embodiment of the present invention, the ammonium salt is generated in the reaction mixture from a Brönsted acid and the ammonia used for the reaction. Non-limiting examples of preferred Brönsted acids are mineral acids, for example hydrochloric acid, sulfuric acid and nitric acid, and carboxylic acids, for example formic acid, acetic acid, propionic acid, oxalic acid, glutaric acid, citric acid or benz
Herwig Juergen
Leininger Stefan
Oenbrink Georg
Schiffer Thomas
Degussa - AG
O'Sullivan Peter
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