CS214922B1 - Alkylene alkylation process of aromatic hydrocarbons - Google Patents

Abstract

The invention relates to a method for the alkylation of aromatic hydrocarbons with alkenes containing at least two carbon atoms in the molecule, using metallic aluminum as a source of catalyst formed in the reaction mixture in the most active form, in the nascent state. The aim of the invention is to make more efficient in a simple and technically feasible way: the production of alkylaromatics, e.g. the production of alkylbenzenes containing 10 to 14 carbon atoms in the molecule used for the production of anionic surfactants. The benzene is treated with either a mixture of an alkene or alkenes and an alkyl chloride, preferably one that has the same number of carbon atoms in the molecule as the alkene. The mixture of organic substances is fed to metallic aluminum, where as a result of the formation of HCl, AlCl3 is formed by reaction with metallic aluminum, which forms an organic complex active as a catalyst for the conversion of aromatic hydrocarbons to alkenes. The reaction can occur without the presence of alkyl chloride, but in the presence of anhydrous HCl. This process produces fewer by-products and the yield of the target product is at least twice as high as in the alkylation of aromatic hydrocarbons with alkyl chlorides. The alkylation reaction is carried out at atmospheric pressure at a temperature of preferably 65 to 80 °C and at a space velocity of 0.5 h-1 to 10 h-1 calculated per alkylating agent.

Description

2

The present invention relates to a process for the alkylation of aromatic hydrocarbons by alkenes in the presence of metallic aluminum. The principle of this method is the simultaneous feeding of aluminum-based aromatic hydrocarbon, alkene, alkyl halide and / or anhydrous hydrogen halide. For metallic aluminum, a mixture consisting of individual alkenes or a mixture of alkenes of individual aromatic hydrocarbons, or mixtures thereof, of alkyl halides or a mixture of alkyl halides at a temperature of 25 ° C to 120 ° C, at a rate of 0 ° C 5 h-1 to 10 h-1 calculated alkylating agent. Czechoslovak Patent No. 85,511 discloses a method for the continuous alkylation of aromatic hydrocarbons with alkyl chlorides using activated aluminum metal.

According to the present invention, the use of aluminum metal as a source of catalytic system in the state is solved by alkylating aromatic hydrocarbons with alkenes containing at least 2 carbon atoms in the molecule by the presence of an alkyl halide containing preferably the same number of carbon atoms in the molecule as alkene or). anhydrous hydrogen halide. The alkyl halide is involved in the alkylation reaction to liberate the hydrogen halide. The hydrogen halide formed in the alkylation reacts with metallic aluminum to form aluminum chloride forming liquid organic complexes of the high-activity catalytic alkylation system with the aromatic hydrocarbons present.

The liquid aluminum halide catalyst system, in the most active state, can also be prepared by supplying anhydrous hydrogen halide to an aluminum carbonate flooded with an aromatic hydrocarbon.

The hydrogen formed by the reaction of the halogen hydrocarbon with metallic aluminum is removed from the reaction medium.

As alkylating agents, straight chain and branched alkenes having a double bond at the end or in any position within the chain can serve. It can be alkene formed by the pyrolysis of hydrocarbons, thermal or catalytic cracking of hydrocarbons, catalytic dehydrogenated alkyne alkenes, oligomerization, disproportionation and copolymerization alkenes.

As the alkyl halide, mono-, di-, tri- and poly-halides can be used in the form of mono-, di-, and polytropic derivatives. Preferably, monohalogenerates having the same number of carbon atoms in the molecule as the alkene are used to alkylate the aromatic hydrocarbon. In such a case, the alkylation of the aromatic hydrocarbon with an alkyl halide produces the same product as the alkylene alkylation. The separation of the alkylation mixture is thereby simplified. In practice, alkyl chlorides are currently the most widespread.

The process according to the invention can be alkylated for example with benzene, mono-, di-, tri- and polyalkylbenzenes, naphthalene and its alkyl derivatives, tri- and polycyclic aromatic hydrocarbons, phenol, mono-, di-, tri- and polyalkylphenols. nols, naphthols and their alkyl derivatives.

The molar ratio of alkyl halide to alkenes can vary widely during alkylation, depending both on the halogen content of the alkyl halide and, depending on the amount of hydrogen halide added to the reactant and on the desired conversion of alkenes.

At least one mole of hydrogen halide 50 moles of alkene must be fed to the aluminum metal bed if no alkyl halide is present.

The hydrogen halide does not need to be introduced into the reacting alkylation mixture when the mole ratio of alkyl monochloride to alkene is 1: 30.

For example, the molar ratio of the aromatic hydrocarbon to the alkene or to the mixture of alkenes and alkyl halide may range from 0.6: 1 to 1:12, depending on the desired composition of the target alkylaromate.

Alkylation of aromatic hydrocarbons with alkenes takes place in the presence of activated aluminum in the temperature range of 25 ° C to 120 ° C at atmospheric pressure or pressure given by the resistance of the alkylation device. Alkylation of aromatic hydrocarbons occurs at a volume rate of 0.5 h -1 to 10 h -1 calculated on an alkene, or a mixture of alkenes, respectively a mixture of an alkene, or an alkene with an alkyl halide, or with alkyl halides, i.e., calculated on the alkylating agent.

To accelerate the alkylation reaction, aluminum metal is preferred. It may be soaked with anhydrous hydrocarbon or an alkylating mixture, preferably at an elevated temperature of 30 ° C to 75 ° C, with anhydrous halide acids.

Activation of aluminum can be accomplished by laminating the halides of the elements known as alkylation catalysts, such as aluminum chloride, zinc chloride, fluoridoboronium, antimony trichloride.

The simplest way of activating metal aluminum is to overlay it with a liquid organic halide complex separated from the alkylation mixture.

Alkylation of aromatic hydrocarbons with alkenes in the presence of activated aluminum can occur in batch reactors or column reactors operating continuously. Depending on the type of reactor, the aluminum is fed to the reactor either in the form of powder, chippings, pulp, or in the form of granules, chips, rollers, cubes, chips,

Claims (2)

3 bodies obtained by pouring molten aluminum into water. Advantages of the process for alkylation of aromatic hydrocarbons with alkenes according to the present invention are the following: - simplicity of alkylation apparatus with high throughput per unit volume of reactor, - high content of alkyl alkylate in the alkylation mixture, - reduced production costs due to increased alkylaromate content in the alkylate and thereby reduced energy consumption on mainly due to the alkylation of aromatic hydrocarbon metal alkyl halides, - the relatively low cost of construction equipment materials compared to the process of alkylating aromatic hydrocarbons with alkenes in the presence of hydrogen fluoride or boron trifluoride and acocatalyst, - reduced by-product formation, in particular, the organic halide complex as compared to the alkylation of aromatic hydrocarbons with alkenes such as aluminum chloride, - high purity of the target product mainly from the point of view of alkylindenes, the formation of organic aluminum chloride complex, thereby reducing the amount of chemical science. Thus, the environment will be improved. EXAMPLE 1 One mole of a C1 to C13 alkyl chloride fraction is continuously added to a 75 cm layer of aluminum granules having a diameter of 10 to 20 mm flooded with an organic aluminum chloride complex in benzene and heated to 70 DEG C. 12 and a chlorine content of 10% by weight, one mole of normal Cu-C13 alkenes having an average molecular weight of 168, a double bond statistically divided into a carbon chain length and a purity of 96% and 12 mole benzene. The slurry of alkyl chloride and alkenes feeds onto the aluminum layer at a rate of 6 h -1. After leaving the reactor, the reaction mixture is cooled to 20 ° C, the organic aluminum chloride complex is separated in the form of a heavier liquid and withdrawn from the pump by the pump. The alkylbenzene mixture with unreacted benzene was subjected to transfer and 3% sodium hydroxide solution and subjected to fractionation. Benzene is distilled off under atmospheric pressure. Unreacted alkanes are distilled off at 13.3 kPa and the alkylbenzenes are distilled off in a further column under 10 kPa vacuum. Polybenzenalkanes and polyalkylbenzenes are withdrawn from the bottom of the second vacuum column. It has been found that the benzene-free alkylate has the following composition: 23% by weight of n-alkanes Cu to C13, 70% by weight of alkylbenzenes having a purity of at least 98% and 7% by weight of higher hydrocarbon feeds. The alkylenes in the alkylbenzenes were 7% by weight. EXAMPLE 2 The procedure is the same as in Example 1, except that 2 moles of normal Ct1-C13 alkanes of beacons beacons statistically distributed over the length of the carbon chain, 10 moles of benzene and 2/3 mol of HCl, are continuously dosed into the layer of activated aluminum granules. After separation of the organic aluminum chloride complex and distillation of the unreacted benzene, an alkylate was obtained which contained 3% alkanes and 2% higher aromatic hydrocarbon 95% target alkylbenzenes of practically free alkylindanes. OBJECT A process for the alkylation of aromatic hydrocarbons with alkenes, characterized in that the individual alkenes contain at least two carbon atoms in the molecule, or a mixture of alkenes and individual aromatic hydrocarbons, or a mixture thereof, together with the individual alkyl halides or the alkyl alcohol mixture. of at least one mole alkyl halide per 30 moles of alkene or alkenes a) or with a hydrogen halide in the present invention at least one mole of hydrogen halide 50 moles of alkene is contacted with metallic aluminum at a temperature of 25 ° C to 120 ° C, volume 0.5 hours -1 up to 10 h ”1 calculated on the alkylating agent. 2. A method according to claim 1, wherein the aluminum is activated with anhydrous halide acids or elemental halides known as alkylation catalysts.