JPH02215732A - Alkylation catalyst of toluene and preparation thereof - Google Patents

Abstract

PURPOSE: To obtain a catalyst for alkylating toluen containing Na₂O on a K₂CO₃ support, easy in the treatment of a starting material and having the same activity as an alkali metal catalyst, by mixing Na₂O and K₂CO₃.

CONSTITUTION: Na₂O and K₂CO₃ are heated at 260-280°C for 0.5-1 hr pref. under reduced pressure to obtain the catalyst containing Na₂O on a K₂CO₃ support Na₂O and K₂CO₃ do no show any catalytic activity independently but, though no chemical reaction is not generated between Na₂O and K₂CO₃ in the above mentioned catalyst, this catalyst shows excellent catalytic activity. The proper concn. of Na₂O in the catalyst is 10-70% (pref., 40-60%). The alkylation of toluene by propylene is designated as an example and the main product in this case is isobutylbenzene.

COPYRIGHT: (C)1990,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a toluene alkylation catalyst and a method for producing the same.

[Prior Art and Problems] As is well known, an alkali metal catalyst is suitable for alkylating the side chain of an alkyl aromatic compound with an olefin, and metallic sodium or metallic potassium is dispersed on an inorganic or graphite carrier. discloses a catalyst containing metallic sodium. British Patent No. 1.289.28
No. 0 discloses a catalyst produced by dispersing sodium and/or lithium on a non-aqueous potassium compound. Finnish patent application no. 8B53[f3, also by the present inventor, refers to a catalyst in which sodium is thermally dispersed from a sodium-containing compound onto the surface of solid K 2 CO 3 .

One of the disadvantages of these catalysts is that the preparation and handling of the catalyst is complicated, the activity at high temperatures is relatively low, and the activity decreases rapidly due to tarring and coking.

[Means for Solving the Problems] Compared to the above-mentioned catalysts, the catalyst of the present invention has easier processing of the starting material and, moreover, has an activity similar to that of an alkali metal catalyst.

The catalyst of the present invention contains sodium oxide (Na21) on a potassium carbonate (K2COG) support.

The method for producing the catalyst of the present invention is to oxidize IJium (N a 2
It is characterized by mixing O) and potassium carbonate (KaCO3).

The catalyst of the present invention used for the alkylation of toluene comprises sodium oxide (Na2) on a potassium carbonate (K2CO3) support.
It is characterized by a system containing O).

The catalyst of the present invention can be produced simply by mixing sodium oxide and potassium carbonate and then heating the mixture. Heating temperature is 100-400℃, preferably 280-280℃
The heating time is 0.5 to 1 hour. It is advantageous, but not an absolute requirement, for this heating to be carried out under reduced pressure.

It is surprising that the catalyst of the present invention does not exhibit any catalytic activity when using either sodium oxide or potassium carbonate alone. Furthermore, according to X-ray diffraction analysis of the final catalyst, both sodium oxide and potassium carbonate phases were observed, so no chemical reaction occurred between sodium oxide and potassium carbonate.

The catalyst of the present invention was tested in the alkylation reaction of the side chain of toluene with propylene.

This alkylation reaction can be explained by the following reaction formula: toluene isobutylbenzene The main product obtained in this reaction is isobutylbenzene. n-phthylbenzene, 4- which is a propylene dimer
Methyl-1-pentene is produced as a by-product as a result of side reactions.

The test was carried out in an l da' continuous microreactor.

After the reaction, the gas and liquid phases were analyzed by gas chromatography.

[Example] Next, a method for producing the catalyst of the present invention and an alkylation reaction using the catalyst will be described with reference to Examples, but the present invention is not limited thereto.

The catalyst was heated to l da3 Paar at 270°C in a steel reactor.
, prepared under reduced pressure. The desired amounts of sodium oxide and potassium carbonate were weighed and charged, and the container was sealed and reduced pressure was applied. The mixture was heated to 260°C to 280°C and the temperature was 0°5 to 1.0°C.
Holds time.

A catalyst of Gll was prepared, but its sodium content was 0.
It was varied in the range of ~100% by weight.

11 The finished catalyst exhibits a dark gray or brown color. When producing catalysts with a sodium oxide content of 14 to 90% by weight, a metallic phase can be observed on the walls of the reactor. X-ray diffraction method (
MRD). The phases observed in the catalyst in this diffraction analysis are sodium oxide, potassium carbonate and possibly sodium metal. Sodium oxide has large crystals and a high concentration. The low and broad nature of these peaks indicates that the potassium carbonate is either small crystals or coated with sodium oxide.

The catalyst was used in a reaction to alkylate the side chain of toluene with propylene. This test was conducted in an ldm3Parr autoclave and continuous microreactor.

The reaction conditions were chosen as follows: reaction time t=19 hours, reaction temperature T: 175°C, toluene/propylene molar ratio n(T)n(P)=0.7, catalyst mass −=
23.0 g of catalyst was charged into the reactor under nitrogen atmosphere. The reactor was closed and vacuum applied. Toluene was charged using vacuum through a valve on the reactor lid. Propylene was fed into the reactor in liquid form.

After the reaction (175°C, 19 hours), the gas and liquid phases were analyzed by gas chromatography.

/I - The main product obtained in this reaction was isobutylbenzene CIBB). The reaction mixture obtained as a result of the side reaction also contains n-butylbenzene (NBB) and 4-methyl-1-pentene (4MI), which is a dimerized product of propylene.
P), and isomerized products of 4-methyl-1-pentene, and various hexene isomers.

The test results are shown in Table 1. From the product composition, the conversion of starting materials, the selectivity of various product components, and the activity of the catalyst with respect to IBB were calculated. FIG. 1 is a plot of toluene and propylene conversion to product versus sodium oxide in the catalyst. Figure 2 shows the catalytic activity g-I
It shows the activity of the catalyst expressed as BB/(g-cat).

(Left below) As can be seen from Table 1 and Figures 1 and 2, the conversion rate and activity in the reaction are highest when the sodium concentration is 60% by weight. However, sodium oxide is 2O or 40
It can be seen that the results are not too bad even in terms of weight percentage.

When the Na*O/K*COa catalyst was compared with the B%Na/CO, catalyst, the activity and conversion rate of the catalyst was 2O. The 40 and 60 wt% oxide catalysts gave much better results. N tested under the same conditions
With a/K2CO3 catalyst, the conversion rate of toluene is 3
0%, propylene conversion rate is 42%, catalyst activity is 4-5
・IBB/(g-cat), whereas the conversion rate of the catalyst containing 110% by weight of sodium oxide 2O-1 is 46~
B is 5% and 64-74%, and the catalytic activity is 5-7.
IBB/(g-cat).

In addition, the oxide catalyst was easily activated and no induction period was observed. In other words, the reaction pressure began to drop immediately after the reaction temperature rose to 175°C. The alkali metal catalyst required about 1 hour to start the reaction.

A significant difference between alkali metal and oxide catalysts is the isomerization efficiency for 4-methyl-I-pentene in the latter case. The selectivity for the formation of 4-methyltopentene isomers is approximately twice as high in the case of oxide catalysts as in the case of alkali metal catalysts. However, this isomerization reaction can be reduced by lowering the temperature and shortening the reaction time.

For testing in a continuous microreactor and 17 degrees 4%N
A2O/K2CO3 catalyst was chosen. The test parameters were as follows: toluene feed rate of approximately 9g;
/br, propylene feed rate approximately 2O g/hr, reaction temperature 170°C, reaction pressure 90 bar, catalyst f1 2B
The g.Na2O/KzCO3 catalyst is considered particularly suitable for producing isobutylbenzene in a continuous reactor. The reason for this is that the production of heavier tar components is particularly less than that of NBB. The tar content does not increase in either case, even if the temperature increases or the catalyst becomes more aged. Na2O/
Although the KaCOa catalyst is more like a fine powder, no pressure loss is observed in the reactor because the catalyst is not contaminated by tar. Therefore, the temperature inside the reactor can be raised to 200°C. N a 2 O / K QC0
The disadvantage of the 3-catalyst is that the dimerization product is 4-methyl-
It has a tendency to form 2-pentene.

This isomerization tendency is highly dependent on the reaction temperature. 150℃
When the temperature is lowered to , this isomerization ratio becomes Na/Ka
Reduced to close to that of CO3 catalyst (blank below)

[Brief explanation of the drawing]

FIG. 1 is a graph showing the conversion rates of toluene and propylene with respect to the concentration of sodium oxide in the catalyst, and FIG. 2 is a graph showing the catalytic activity to isobutylbenzene with respect to various concentrations of sodium oxide in the catalyst. Agent Akira Akimoto 14.・1 other person

Claims (9)

[Claims] (1) Toluene alkylation catalyst containing sodium oxide (Na_2O) on a potassium carbonate (K_2CO_3) support. (2) The catalyst according to claim 1, wherein the sodium oxide concentration in the catalyst is 10 to 70%. (3) The catalyst according to claim 1, wherein the sodium oxide concentration is 40 to 60%. (4) A method for producing a toluene alkylation catalyst containing sodium oxide (Na_2O) on a potassium carbonate (K_2CO_3) carrier, the method comprising:
A manufacturing method consisting of mixing O) and potassium carbonate (K_2CO_3). (5) The method according to claim 4, wherein the concentration of sodium oxide in the catalyst is 10 to 70% by weight. (6) The method according to claim 4, wherein the concentration of sodium oxide in the catalyst is 40 to 60% by weight. (7) The catalyst according to claim 1 for use in the alkylation of toluene with propylene. (8) The catalyst according to claim 7, wherein the sodium oxide concentration in the catalyst is 10 to 70%. (9) The catalyst according to claim 7, wherein the sodium oxide concentration in the catalyst is 40 to 60%.