CA1088941A

CA1088941A - Process for producing bis(cycloalkeno)-pyridines

Info

Publication number: CA1088941A
Application number: CA286,004A
Authority: CA
Inventors: Helmut Beschke; Heinz Friedrich; Axel Kleemann
Original assignee: Deutsche Gold und Silber Scheideanstalt
Current assignee: Evonik Operations GmbH
Priority date: 1977-08-16
Filing date: 1977-09-01
Publication date: 1980-11-04
Also published as: JPS5432475A; GB1550726A; NL184002C; DE2736888A1; IL52887A; CH631708A5; BE858391A; FR2400510B1; JPS6232189B2; NL7709708A; IL52887A0; NL184002B; DE2736888C2; IT1143598B; FR2400510A1; BR7705883A

Abstract

ABSTRACT OF THE DISCLOSURE
The present invention provides a process for producing 2,3:5,6-bis-cycloalkeno)pyridines from cycloalkanones, in which cycloalkanones having at least one reactive methylene group adjacent to the keto group are reacted with aliphatic aldehydes and with ammonia in the gas phase at temperatures from approximately 250 to 550°C in the presence of a catalyst having dehydrating and dehydrogenating properties.

Description

1~ 194~1 The present invention relates to a process for producing

2,3:5,6-bis(cycloalkeno)pyridines. These pyridines are important intermediate products for the production of medicines, plant protective agents and plastics.
The production of 2,3:5,6-bls(cycloalkeno)pyridines by reacting the corresponding bis(2-oxo-cycloalkyl)methanes with ammonium acetate is known. The bis(2-oxo cycloalkyl)methanes also are first converted into the oximes or semicarbazones, which are then hydrolized with acids to the 2,3:5,6-bis(cycloalkeno) pyridines (Bull. soc. chim. France 5 (1957), 447-449). The bis--(2-oxo-cycloalkyl)methanes are obtained by condensing the corresponding cycloalkanones with formaldehyde or by condensing the corresponding cycloalkanones with morpholine to the enamines and their reaction with formaldehyde (ser. 95(1962), 1495-1504).
It is also known to produce 2,3 5,6-(cycloalkeno)-pyridines by reaction of cycloalkanones with the corresponding hydroxy-methylene-cycloalkanones and perchloric acid and treatment of the nascent 2,3:5,6-bis(cycloalkeno)pyrilium-perchlorate with ammonia (Zhurnal Organ. Khim. 2 (1966), 1864-1869). Moreover it is known that 2,3:5,6-bis(cycloalkeno)pyridines are formed when cycloalkanones are heated in hexamethyl-phosphoric acid triamide.
The corresponding alkyl-substituted 2,3:5,6-bis(cycloalkeno)-pyridines are formed in the same manner from alkyl-substituted cycloalkanones (Tetrahedron Letters 10 (1972), 929 932).
The known-processes are not suitable for use on an industrial scale as they are costly and cumbersome and result only in small yields.
A process for producing 2,3:5,6-bis-(cycloalkeno)pyridines from cycloalkanones has now been found in which cycloalkanones, which have at least one reactive methylene group adjacent to the keto group, are reacted at temperatures from approximately 250 to 550C with aliphatic aldehydes and with ammonia in the gas . . , i : ':' . . .
.~ , . .

~ l(p~
-phase in -the presence of a catalyst having dehyarating and dehydrogenating properties. According to this process the 2,3-5,6-bis~cycloalkeno)pyridines are produced from simple, readily obtainable substances in a single-stage reaction. In contrast to known processes the process according to -the invention is very suitable for use on an industrial scale.
According to the invention cycloalkanones having the general formula ,~=o wherein Z represents an aliphatic chain containing 2 to 16 carbon atoms, said chain being kranched, if required, and the branchings of said chain forming one or several rings, if required, and Z
represents particularly an alipha~ic chain containing 3 to 10 carbon atoms, said chain being branched, if required, are reacted with aldehydes having the general formula ~;
O = CH - R II
wherein R represents hydrogen, alkyl groups which are branched, if required, and contain 1 to 6, preferably 1 or 2 carbon atoms, and with ammonia to compounds having the general formula z ~ III

wherein Z and R have the meanings defined hereinbefore.

Suitable cycloalkanOnes (I) are, for example, cyclobut-anone, cyclopentadecanone, cyclohexadecanone, cyclooctadecanone,

3,5,5-trimethyl cyclohexanone, camphor, l-decalone, 8-keto-tricyclodecane, carvone, cyclooctanone, cyclodecanone, 2-methyl-cyclohexallone, 3-methyl-cyclohexanone, 4-methyl-cyclohexanone, 2,2,4-trimethyl-cyclopentanone, methone and particularly 94~1 .
cyclopentanone, cyclohexanone, cycloheptanone and cyclododecanone.
Suitable aldehydes (II) are, for example, propionalde-hyde, butyraldehyde, isobutyraldehyde, acetaldehyde and particu-larly formaldehyde.
If required, the reactants are used as solutions, for example, as solutions in water and/or lower alkanols, such as methanol, ethanol and propanol-(2). The ketones and aldehydes can also be used in the form of substances from which they are then set free under the conditions oE the process, for example, as hemiacetals, the aldehydes also as polymers, and the formaldehyde, for example, as polyformaldehyde or as trioxane.
The conditions of the reaction, such as temperature and pressure, and the relative quantitites of the substances to be reacted as well as the residence times are interdependent to some extent, if required, and possibly depend on the kind of substances to be reacted and on the kind of catalyst. ~-The reaction is usually carried out at temperatures ;~
between approximately 250 and 550C. In most cases temperatures between approximately 300 and 500C, particularly between 350 and 450C are preferred. It is favourable to operate at pressures from approximately 1 to 4 bars, but lower or higher pressures are also suitable although it is expedient to use pressures -which do not differ substantially from these values so that simple apparatus can be used.
The ratios of cycloalkanone (I) to aldehyde (II) can be chosen arbitrarily to a great extent. They may be stoichio-metric and also below or above the stoichiometric value. It is . usually advantageous to use approximately 0.2 to 2 moles of aldehyde (II) per mole of cycloalkanone (I). Approximately 0.3 to 1.0 mole, particularly 0.4 to 0.8 mole of aldehyde (II) per mole o cycloalkanone (I) is preferred.

'.

.

94~

The ammonla can be present during the reaction in largely arbitrary amounts, i.e., from below to above stoichio-metric amounts. In most cases it is desirable that at least approximately 0.5 mole but more than approximately 100 moles of ammonia are present per mole o~ cycloalkanone (I). Approximately 1 to 20 moles of ammonia, preferably 2 to 15 moles of ammonia, particularly 3 to 12 moles of ammonia per mole of cycloalkanone (I) are advantageous.
The reaction occurs in the gas phase. Starting suhstances which possibly are in an other state are flrst converted into the gaseous condition. It may be desirable to use the gases from cycloalkanone (I), aldehyde (II) and ammonia diluted with inert gases. For example, water, vapour, air and particularly nitrogen are suitable inert gases. If the starting substances are applied in the form of solutions, then gases diluted by the solvent result. It usually is expedient that not more than a -total of approximately 20 moles of inert gas, preferably approximately 0.5 to 10 moles of inert gas, particularly 1 to 5 moles of inert gas are present per mole of cycloalkanone (I).
Substances havin~ dehydrating and dehydrogenating properties are suitable as catalysts, as for example, the catalysts described in Hydrocarbon Processing, 47 (1968), 103 to 107 and based on aluminium compounds, such as aluminium oxide and aluminium silicate, if required with additions of other metallic oxides and fluorides. Catalysts produced by means of the processes according to the laid-open German Applications 2 151 417j 2 224 160 and 2 239 801 are used with special advantage. They are compounds of the elements Al, F and O which have been pretreated at temperatures from approximately 550 to 1200C and additionally contain at least one element of group II, III or IV of the periodic system or at least two ' elements of the Group II, IV, V or VI of the Perlodic system or at least one element of the second principal group of the Periodic system. These catalysts are used in a fixed bed or preferably in a fluidized bed. Residence times between approxima-tely 0.5 and 5.0 seconds usually result.
The gas mixtures obtained in the reaction can be further treated inthe usual manner by washing the gases with a liquid, particularly water or methanol, or by further separation by means of extraction and distillation.
10A process according to the laid-open German Application 2 554 946 in which the gas mixtures are not washed but cooled and -thus partially condensed in such a way that possible excess ammonia remains in the residual gas and is directly recycled therewith is used with special advantage.
The present invention will be further illustrated by way of the following Examples.
E ample 1 A fixed bed reactor having a volume of 100 ml was filled with a catalyst, which had been produced from aluminium oxide, magnesium nitrate and ammonium hydrogen fluoride according to the laid-open German Application 2 239 801 and had an atomic ratio of aluminium to magnesium to fluoride of 1000 to 25 to 50. A gas mixture of 49 g (0.50 mole) of cyclohexanone, 25 g (0.25 mole) of formaldehyde (as a 30~ aqueous solutions), 44.8 standard litres (2.0 moles) of ammonia and 22.4 standard litres (1.0 mole) of nitrogen was passed over this catalyst per hour. The temperature in the reactor was kept at 400C. Cyclohexanone and formaldehyde were reacted completely. 17.8 g of 2,3:5,6-bis(cyclohexeno)pyridine were obtained per hour corresponding to a yield of 38%, relative to cyclohexanone applied. The product had a boiling point of 124 to 126C at 2 millibars. Upon recrystallization from petroleum ether the product had a melting point of 74C

The procedure of Example 1 was followed in the .
Examples hereafter.
Ex p e 2 Starting substances cyclododecanone, formaldehyde, ammonia and nitrogen in the molar ratio of 6:3:24:12 (formaldehyde applied as trioxane) catalyst of aluminium oxide, magnesium nitrate, titanium tetrafluoride according to the laid-open German Application 2 224 160, atomic ratio of aluminium to magnesium to titanium to fluoride of 1000:25:25:100 reaction temperature 420C
reaction rate 82% of the cyclododecanone product 2,3:5,6-bis(cyclododeceno)pyridine melting point 155C (upon recrystallization from toluene) yield 34g6, relative to cyclododecanone applied Example 3 Starting substances cyclopentanone, formaldehyde, ammonia and nitrogen in the molar ratio of 2:1:8:4 (formaldehyde applied as a mixture of 30~ of formaldehyde and 70~ `~
of water) catalyst of aluminium oxide, magnesium nitrate and fluosilicic acid according to the laid-open German Application 2 151 417, atomic ratio of aluminium to magnesium to silicon to fluoride of 1000:24:25:156 reaction temperature 390C
reaction rate 75% of the cyclopentanone product 2,3:5,6-bis(cyclopen-tQno) pyridine, melting point 90C
(upon recrystallization from toluene) yield 27~, relative to cyclopentanone applied '",, ' ' ' ' , . ;, , '~ . . , -94~
Example 4 Starting substances cyclopentanone, formaldehyde, ammonia and nitrogen in the molar ratio of 2:1:8:4 tformaldehyde applied as a mixture of 30% of formaldehyd-and 70% of water) catalyst as in example 1 reaction temperature 400C ~ -reaction rate 72~ of the cycloheptanone product 2,3:5,6-bistcyclohepteno) pyridine, melting poin-t yield 25~i, relative to cycloheptanon~ -appl ed .

'; .

:" '; : ,

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for producing a 2,3:5,6-bis(cycloalkeno) pyridine having the general formula:

wherein Z represents an aliphatic chain, which chain may be branched, containing 2 to 16 carbon atoms and R is hydrogen or an alkyl group with 1 to 6 carbon atoms, which comprises reacting a cycloalkanone having the general formula:

wherein Z is as defined above, with an aliphatic aldehyde having the formula R - CH = O, wherein R is as above and with ammonia in the gas phase at temperatures from approximately 250 to 550°C in the presence of a catalyst having dehydrating and dehydrogenating properties.

2. A process according to claim 1, in which the reaction is carried out at temperatures from approximately 300 to 500°C.

3. A process according to claim 1, in which the reaction is carried out at temperatures from approximately 350 to 450°C.

4. A process according to claim 1, 2 or 3, in which aluminium silicate is used as the catalyst.

5. A process according to claim 1, 2 or 3, in which compounds of the elements Al, F and O which have been pretreated at temperatures from approximately 550 to 1200°C and additionally containing at least one element of Group II, III or IV of the Periodic system are used as the catalyst.

6. A process according to claim 1, 2 or 3, in which the compounds of the elements Al, F and O which have been pretreated at temperatures from approximately 550 to 1200°C and additionally contain at least two elements of Group II, IV, V
or VI of the Periodic system are used as the catalyst.

7. A process according to claim 1, 2 or 3, in which compounds of the elements A1, F and O which have been pretreated at temperatures from approximately 550 to 1200°C and additionally contain at least one element of the second principal Group of the Periodic system are used as the catalyst.

8. A process according to claim 1, 2 or 3, in which approximately 0.2 to 2.0 moles of the aldehyde are used per mole of cycloalkanone.

9. A process according to claim 1, 2 or 3, in which approximately 1 to 20 mole of ammonia are present per mole of cycloalkanone.

10. A process according to claim 1, 2 or 3, in which inert gases are present.

11. A process as claimed in claim 1, 2 or 3 in which Z has 3 to 10 carbon atoms and the alkyl groups have 1 or 2 carbon atoms.

12. A process as claimed in claim 1, 2 or 3, in which the cycloalkanone is selected from cyclobutanone, cyclopentadeca-none, cyclohexadecanone, cyclooctadecanone, 3,5,5-trimethyl cyclohexanone, camphor, 1-decalone, 8-keto-tricyclodecane, carvone, cyclooctanone, cyclodecanone, 2-methyl-cyclohexanone, 3-methyl-cyclohexanone, 4-methylcyclohexanone, 2,2,4-trimethyl-cyclopent-anone, menthone, cyclopentanone, cyclohexanone, cycloheptanone or cyclododecanone and the aldehyde is selected from propionalde-hyde, butyraldehyde, isobutyraldehyde, acetaldehyde and formalde-hyde.

13. A process according to claim 1, 2 or 3, in which approximately 0.3 to 1.0 moles of the aldehyde are used per mole of cycloalkanone.

14. A process according to claim 1, 2 or 3, in which approximately 0.4 to 0.8 moles of the aldehyde are used per mole of cycloalkanone.

15. A process according to claim 1, 2 or 3, in which approximately 2 to 15 moles of ammonia are present per mole of cycloalkanone.

16. A process according to claim 1, 2 or 3, in which approximately 3 to 12 moles of ammonia are present per mole of cycloalkanone.