DD154983A1 - METHOD OF ISOBUTENOLIGERIZATION - Google Patents

Abstract

The invention relates to a process for isobutene oligomerization using pure isobutene or C 4-hydrocarbon mixtures, as obtained after but-1,3-diene extraction or in refinery plants. It has been found that, with the aid of zeolites modified by organoaluminum compounds, it is possible to prepare isobutene oligomers with a wide variety of possible uses in a continuous and technically simple process.

Description

225,596

Title of the invention

Process for isobutene oligomerization

Applicability of the invention

The invention relates to a process for the preparation of isobutene oligomers by oligomerization of pure isobutene and by selective oligomerization of the isobutene from C. hydrocarbon geraischen, as z. B. in pyroly, seanlagen for ethylene production and in refinery plants arise. The other unsaturated and saturated hydrocarbons of the C. mixtures remain unreacted and are available for further reactions.

Characteristic of well-known, tecnical solutions

It is known that isobutene, but-1-ene and E- and Z-but-2-ene can be oligomerized and polymerized in a cationic way. The isobutene shows the greatest tendency to polymerize, which manifests itself in the high reaction rate and the achievable high molecular weights of the polymers.

It is also known that oligomerizations of isobutene can be carried out from its mixtures with other saturated and unsaturated components, but only in the rarest of cases are pure oleo-oligomerizates obtained.

Thus, according to US Pat. No. 3,960,978, crystalline aluminosilicate zeolites of the types Z.SM-5 and ZSM-11, which can be used with

2 - 22 5 596

) -. * 18 H ₂ O or with CrClo, make oligo-initiations, it being possible to set a low aromatization activity by suitable pretreatment of the zeolites, so that not more than 20 % aromatics are formed.

According to GB-PS 1,489,646 'zeolites containing heavy metal ions of the nickel or cobalt are also used for the oligomerization of Cp-C, --- olefins, at temperatures between 93 and 427 ⁰ C.

The methods mentioned here show the disadvantages that side reactions such as aromatizations take place and that higher temperatures have to be used, which is uneconomical because of the high energy costs. In addition, the modification of the aluminosilicates is often quite complicated and therefore time-consuming and costly,

Object of the invention

The aim of the invention is to develop an economical and efficient process for the preparation of oligomers of isobutene both from the pure monomer and in a particularly advantageous manner from the mixture of isobutene with other saturated and unsaturated C, hydrocarbons out, the disadvantages known methods are eliminated.

Indication of the essence of the invention

The invention has for its object to develop an economical and efficient process for the preparation of homo-isomers of isobutene from both the pure monomers and from C ^ -hydrocarbon mixtures without prior separation of the isobutene.

The object is achieved according to the invention by pure isobutene or isobutene, which is dissolved in a C 2 hydrocarbon mixture with other saturated and unsaturated components.

-, 3 - 225 596

is present, is oligomerized on modified zeolites.

The modification of the zeolites, which are aluminosilicates of the Wolfen-Zeosorb 10 X type, is carried out by organoaluminum compounds of the AlR ₂ OR 'type, the said compounds used for the modification being in the form of a hydrocarbon solution or in pure form, as previously described heated zeolites are applied. In the compounds used for modification R and R 'are aliphatic or cycloaliphatic hydrocarbon radicals, preferably ethyl and butyl substituents. The zeolites modified in the manner mentioned can be used immediately for the oligomerizations without further pretreatment.

The Oligotnerisationsn can be carried out in a conventional manner both in the gas phase and in the liquid phase either using a co-solvent, eg, from the series of saturated aliphatic or cycloaliphatic hydrocarbons or in a gasoline fraction, or without auxiliary solvent.

The oligomerization temperatures are between -20 and +150 ⁰ C, but preferably between +20 and +70 ⁰ C, wherein a pressure between normal pressure and a maximum of 35 atu sets,

The examples given are intended to illustrate the process according to the invention.

Execution game

1, 1 kg of zeolite Wolfen-Zeosorb 10 X are placed in a 21-quartz glass flask, which is heated to 400 ⁰ C. Within two hours there is ater removed at a pressure of 5 Torr, the adsorbed V /, · After cooling down to 20 ⁰ C 0.35 Raol diethylaluminum to the support are applied _e The catalyst thus prepared is active without · further treatment.

₄ _ 2 2 5 5 9

2. In the oligomerization apparatus shown in the figure, a total of 1.5 kg of the catalyst prepared according to Example 1 are introduced into the two tube reactors 1. Continuously purified isobutene is withdrawn and passed through the tubular reactor at a temperature of 40 ⁰ G from a "reservoir. 2 The effluent from the tubular reactors oligomer is collected in collecting vessels 3 at about 40 ⁰ G, so that the solubility of the unreacted isobutene in At a flow rate of 160 1 isobutene per hour per kilogram of catalyst, an oligomer of the following composition is produced at 100% conversion: 65 % of diisobutene

25 % triisobutene

6% tetraisobutene

68 % of the diisobutene consists of 2,4,4-trimethylpent-1-ene, 15 % of 2,4,4-trimethylpent-2-ene, 11,5% of 2,3,4-trimethylpent-1-ene and 5 % by capillary gas chromatographic analysis. from 2.3 "4-trimethylpent-2-ene,

In the manner described in Example 2, instead of pure isobutene, a butene fraction of the folloWing composition freed from acetylenes and allenes by known means and methods is passed over the catalyst:

Co-hydrocarbons 1.2%

n-butane 10 % i-butane 5.5. %

But-1-ene 26.5 %

Isobutene 41 % E-but-2-ene S% '

Z-but-2-ene 6 %

But-1.3-diene 0.8 %

At 93% isobutene conversion, an oligomer of the following composition is formed:

- 5 - 2 2 5 5 9 6

68 % diisobutene + codimerate with but-1-ene 23% triisobutene 6 % tetraisobutene

The codimer fraction in the Dimerenfraktion is 10%, so the reaction dal3 Rait at least 95% selectivity based <runs on isobutene.

4. In a glass autoclave with stirring device and a capacity of 2 1 150 g of the catalyst prepared according to Example 1 are charged and 1.5 1 of a 'butene fraction of the composition mentioned in Example 3 was added. With stirring, through which no comminution of the catalyst must take place, the isobutene conversion is complete after about two hours at a reaction temperature of 60 ⁰ C. After relaxing to remove the residual gases, the resulting oligomerizate is subjected to distillation

78% dimers 18% trimers and 2 % tetramers

emerged.

Claims (2)

- 6 - 2255 9 6 Invention claim 1. A process for Isobutenoligomerisation, characterized in that pure isobutene or isobutene of C ^, - hydrocarbon mixtures of ethylene production plants or refineries of modified zeolites, preferably aluminosilicates of the type 10 X is oligomerized and that are used to modify the zeolites aluminum organics AlRpOR type ⁵ in which R and R ^{f represent} aliphatic and cycloaliphatic hydrocarbon radicals, preferably ethyl and butyl substituents, and these organoaluminum compounds are applied in the form of a hydrocarbon solution or in pure form to the previously heated zeolites. 2 * process for Isobutenoligomerisation, characterized in that the oligomerization both-> in the gas phase and in the Plüssigphase at temperatures between -20 and +150 ⁰ C, but preferably between room temperature and +70 C is performed and that in the Plüssigphase without and using an auxiliary solvent, e.g. B. from the series of aliphatic and cycloaliphatic hydrocarbons, is working. For this 1 page drawings