DE2363705A1 - PROCESS FOR MANUFACTURING PURE CYCLOPENTENE - Google Patents

Description

Process for the production of pure cyclopentene (addendum to patent application P 23 26 196.3)

Subject of the patent (patent application P 23 26 I96.3)

is a process for the production of pure cyclopentene, whereby ice, cis-cyclodecadiene- (1,6) with a metathesis catalyst optionally in the presence of a solvent at temperature

or lets react above 0 C,

It has now been found that in a further development of this method Pure cyclopentene can be prepared by using a heterogeneous metathesis catalyst consisting of

a) a carrier material and

b) an oxide of the elements of groups 6a or 7a of the periodic System of elements

used.

In the context of this invention, pure cyclopentene is understood to mean a product which, above all, with regard to the possible subsequent polymerization with the aid of metathesis catalysts does not contain any conjugated dienes such as cyclopentadiene.

The starting product of the process according to the invention, cis, cis-cyclodecadiene (1,6), can be produced by known processes of the prior art. First, cis, trans-cyclodecadiene (1,5) from the inexpensive monomers butadiene and ethylene, which are available in almost unlimited quantities produced (G. Wilke and P. Heimbach, Angew. Chem. JJ5 (1963), page 10). Then this ice, trans-cyclodecadiene (i, 5) with the help of an isomerization catalyst in the ice, cis-cyclodecadiene (1,6) converted (DT-PS 1 230 023 or Dissertation H.G. Nüssel, Ruhr University Bochum (197O), page 89).

7V73

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As is known, metathesis catalysts are homogeneous and Understood heterogeneous catalysts, the compounds of metals of the 5 · to 7 · subgroup of the periodic system, primarily of niobium, tantalum, molybdenum, tungsten and rhenium and, if necessary, compounds of the metals of the 1st to 3rd Main group of the periodic system, e.g. their alkyls or hydrides, optionally with other ligands, such as halogen, Alkoxyl or carboxylate, or contain Lewis acids in their place. In addition, as is known, the metathesis catalysts can contain other activating additives, such as alcohols, epoxides, tert-butyl hypochlorite, Contain peroxides, carboxylic acids, aromatic nitro compounds, vinyl halides, vinyl and allyl ethers and esters.

The heterogeneous metathesis catalysts which can be used according to the invention exist from a) a support material and b) an oxide of the elements .der groups 6a or 7a of the Periodic Table of Elements.

Commercially available aluminum oxides or oxides of the elements of the k. Group of the PSE, preferably silicon dioxide, is used. These refractory oxides usually contain a small amount of alkali metal ions resulting from the manufacturing process. In the case of aluminum oxide, an amount of about 0.2 percent by weight Na 0 is expedient.

Oxides of molybdenum and rhenium are preferably used as catalyst component b), rhenium heptoxide being particularly preferred is.

The heterogeneous catalysts can be prepared once by simply mixing the components. However, it is preferred the method of manufacture in which the carrier material with the solution is impregnated with a suitable compound of the transition metals mentioned above and then activated. Under active

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vierung understood a thermal treatment in which the connections be converted into oxides. In the present process, preference is given to using a catalyst in which aluminum oxide is used impregnated with a solution of a perrhenate, preferably ammonium perrhenate, and then in a stream of air or oxygen is heated so that a conversion of the perrhenate takes place in the oxide. The transfer of the compounds of the above Transition metals into the oxides is generally in the temperature range from 300 to 650 C, preferably in the range from 350 to 45Ο G.

The heterogeneous metathesis catalysts which can be used in the process according to the invention generally contain 1 to 30 parts, preferably 5 to 20 parts, molybdenum or rhenium oxide in the valency level active in the metathesis reaction per 100 parts Carrier material,

The process according to the invention is generally carried out at temperatures carried out above 0 C. The reaction temperature becomes upwards through the thermal stability of the catalyst or through the increase in undesired side reactions and afterwards limited below by the excessively reduced reaction rate. It is advantageous to work at temperatures between 4θ and 180 c, especially between 5 0 and 120 G.

However, care must be taken that the reaction temperature and also the support material of the catalyst are chosen so that that isomerization reactions largely do not occur.

The reaction can, if appropriate, also take place in the presence of a solvent be carried out, which allows the implementation of metathesis reactions with the catalysts mentioned. the most important representatives from the group of aliphatic, alicyclic, aromatic and halogenated hydrocarbons are

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the following: pentane, hexane, heptane, n- and iso-octane, isononane (hydrogenated trimerpropene), n-decane, isododecane (hydrogenated tetramerpropene), Cyclopentane, cyclohexane, methylcyclopentane, methylcyclohexane, ethylcyclohexane, isopropylcyclohexane, cyclooctane, Decahydronaphthalene, hydrogenated terpenes such as pinane and camphan, Cyclohexane and its substitution products, benzene, toluene, o-, m-, p-xylene, ethylbenzene, o-, m-, p-diethylbenzene, n-propylbenzene, Isopropy! Benzene and other mono- to polyalkylbenzenes, tetrahydronaphthalene, Methylene chloride, chloroform, carbon tetrachloride, 1,2-dichloroethylene, trichlorethylene, tetrachlorethylene, chforbenzene, o-dichlorobenzene, trichlorobenzene (mixture of isomers), bromobenzene, Fluorobenzene, 1,2-dichloroethane.

It is essential that the solvents as well as the cis, cis-cyclodecadiene (1,6) free of water and other H-acidic compounds as well as compounds with donor functions (Lewis bases) can be used.

The process according to the invention can be carried out either batchwise or continuously. Appropriately selects such a reaction procedure in which the cyclopentene formed is separated from the reaction zone as soon as possible. It can then optionally be purified by distillation be subjected. The ice, cis-cyclodecadiene (1,6) is used up to complete consumption brought into contact with the catalyst.

The different boiling points of ice, cis-cyclodecadiene- (1.6) and cyclopentene allow the latter to be optimally withdrawn by a suitable choice of the pressure in the reaction apparatus.

The cyclopentene produced by the process according to the invention is particularly suitable for the production of trans-1,5-polypentenamer rubber, which is of great technical interest (cf. Hydrocarbon Processing, December 1972, page 71).

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The following examples serve to illustrate the claimed Procedure.

Examples 1 to 10

Ice, cis-cyclodecadiene (1.6) is poured into a three-necked flask equipped with an internal thermometer and boiling capillary under inert gas submitted. The flask is made up of a circulating apparatus from a riser pipe, a Liebig cooler, a Soxhlet-like one thermostatisxerbaren extractor and one arranged below this graduated dropping funnel equipped with pressure compensation. Of the The extractor is used to take up the heterogeneous metathesis catalyst, the dropping funnel is used to control the catalyst passing ice, cis-cyclodecadiene (1,6) amount from the dropping funnel can flow back into the three-necked flask. The educated Cyclopentene is drawn off by means of a vacuum tube attached above the extractor and condensed in a cold trap.

The extractor each contains 38 g of a catalyst on was produced as follows: 88 g of an aluminum oxide (surface: 300 m / g, pore volume: 0.5 em / g, debris weight: 880 g / l, alkali content: 0.4 percent by weight Nä θ) are with a Solution of 11 g of ammonium perrhenate in 100 ml of distilled water soaked, excess water stripped off on a rotary evaporator, the remaining residue dried in vacuo at 100 to 120 c and then heated in a tube furnace at 380 to 420 c for 5 to 20 hours.

The table below shows the results when changing the process parameters are obtained.

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cn ο co α> ro oo - ^

Ex.
No. variable Reaction
temp. (° C) pressure
(mm) Attempt
duration
(min) received
Cyclopentene
U) CDD - (, 1.6) -
Throughput
per hour
(ml / hl Cyclopentene /
Total throughput
CDD- (I, 6) 1 temperature 60 ■ 146 424 2.7 531 0.71 2 100 147 ' 432 9.7 549 2.45 3 60 146 412 6.0 180 5.14 ■ 4 100 150 424 14.6 184 1 1, 20 5 Dwell time 60 100 433 5.3 570 1, 28 6th 60 100 427 5.8 174 4.68 7th 6o 100 121 8.2 103 39.42 8th 100 148 432 9.7 549 2.45 9 100 146 426 8.2 387 2.98 10 100 146 416 8.4 189 6.41

CO CD CO

Claims (1)

Claims 1. Further development of the process according to the patent. . (Patent application P 23 26 196.3) ^{for the} production of pure cyclopentene, with cis, cis-cyclodecadiene (1,6) with a metathesis catalyst, optionally in the presence of a solvent at temperatures ο
is implemented above 0 C, characterized in that one consisting of a heterogeneous metathesis catalyst a) a carrier material and b) an oxide of the elements of Group 6a or Yes. of the Periodic Table of the Elements used. 2. The method according to claim 1, characterized in that the support material used is an aluminum oxide containing alkali ions used. 3. The method according to claims 1 and 2,
characterized in that an oxide of molybdenum or rhenium is used as catalyst component b). h . Method according to claim 3, characterized in that rhenium heptoxide is used. 5. The method according to claims 1 to h, characterized in that the reaction temperature is 40 to 180.degree. 509 8 2 8/0898 - 8 - OZ 2755 December 20, 1973 6. The method according to claim 5 »" characterized in that the reaction temperature is 50 to 120 ° C. \. 509828/0898