CZ303211B6 - Strongly acid ion exchange catalyst with affinity to lipophilic reagents and process for preparing thereof - Google Patents

Abstract

The present invention relates to a strongly acid ion exchange catalyst with affinity to lipophilic reagents with sulfone aromatic nuclei of polymer skeleton in which 20 to 70 percent of the aromatic nuclei of the catalyst polymer skeleton comprise acyl groups with a chain containing 2 to 12 carbon atoms. The invention also relates to a process for preparing the above-described strongly acid ion exchange catalyst, the preparation process being characterized in that prior introduction by sulfonation of strongly acid groups the polymer skeleton is subjected to the action of am acylation agent at a temperature ranging from 50 degC up to boiling point of the acylation agent, and for a period of 1 to 4 hours.

Description

Strongly acidic ion exchange catalyst with affinity for lipophilic reagents and process for its preparation

Technical field

The present invention relates to a strongly acidic ion catalyst with affinity for lipophilic reagents with sulfonated aromatic nuclei of a polymer backbone and a process for its preparation.

BACKGROUND OF THE INVENTION

The strongly acidic ion exchangers prepared by the sulfonation of styrene-divinylbenzene copolymers are preferably used as catalysts for various chemical processes replacing soluble acids. Conventionally, strong acid ion exchangers produced by virtually complete styrene-divinylbenzene copolymerization are used as catalysts. Only the sterically unavailable and catalytically inactive skeletal domains remain unsulfonated. Due to the presence of strongly acidic sulfo groups, conventional ion exchange catalysts are highly hydrophilic in nature. This renders them well compatible with polar reagents but detracts from their usefulness for reactions involving lipophilic reagents.

Satisfactory results in such cases can be achieved either by the presence of high concentrations of polar reaction components, or by the use of so-called macroreticular types of ion exchange catalysts having a portion of their porous structure independent of polymer swelling. race well above the stoichiometric need (Jerabek K. et al., J. Mol. Catal. A: Chem. 333 (2010) 109-113).

For the reactions of molecules with markedly different polarities, it may be advantageous to combine strongly acidic hydrophilic centers and hydrophobic zones in the catalyst (Mbaraka, I.K .; Shanks, B. H. J. Am. Oil Chem.

Soc. 83 (2006) 79).

In a polymer catalyst, a combination of lipophilic and hydrophilic zones can be formed by copolymerization of functionalized and non-functionalized comonomers (Jerabek, K., Prokop, Z., Revillon, A .: React. Func. Polym., 33, (1997), 103). However, this process requires relatively expensive raw materials and does not allow broad control of the morphology of the resulting catalysts.

The partial sulfonation method is not very suitable for creating the desired high dispersion of functionalized and non-functionalized sites in the polymer mass of styrene-divinylbenzene copolymers (Hanková L, Holub L., Jeřábek K .: React. Funct. Polym. 66 (2006) 592).

Kobayashi and coworkers have described the preparation of hydrophobic catalysts with strongly acidic sulfo groups, but the process proposed by them based on the introduction of very long alkyl or acyl groups into the polymer backbone allows the preparation of catalysts with only a very low concentration of acid groups suitable for special reactions in aqueous media

S., Manabe, K., Kobayashi, S., Org. Letters 5, (2003) 101 and Org. Biomol. Chem. I (2003) 2416).

SUMMARY OF THE INVENTION

SUMMARY OF THE INVENTION The strongly acidic ionic catalyst having affinity for lipophilic reagents having sulfonated aromatic cores of the polymer backbone is characterized in that 20 to 70% of the aromatic cores of the polymeric backbone catalyst contain 2 to 12 carbon acyl groups.

-1 CZ 303211 B6

An essential feature of the process for preparing the catalyst is that before the introduction of the strongly acidic groups by sulfonation, the polymer skeleton is exposed to the acylating agent at a temperature of from 50 ° C to the boiling point of the acylating agent and for 1 to 4 hours.

This method can be further advantageously developed or specified by the following procedures:

Prior to controlled acylation, the acylating agent is allowed to act on the polymer backbone at normal temperature for 1 to 24 h.

Gel or macroreticular copolymers of styrene and technical divinylbenzene containing from 1 to 40 moles are used as the starting basis of the polymer backbone. % divinylbenzene.

The acylating agent contains 2 to 12 carbon atoms and is preferably selected from the group of acyl halides.

Anchoring the acyl groups to the polymer backbone allows the formation of adsorption centers for lipophilic reagents. This is because acylation deactivates the benzene nucleus for subsequent sulfonation, and the unsulfonated benzene nuclei thus retain a lipophilic nature. The alkyl chains of the acyl groups also serve as adsorption centers for the lipophilic reagents. The beneficial effect of the presence of lipophilic reagent adsorption centers on the catalyzed reaction can only be expected in the vicinity of hydrophilic, strongly acidic sulfo groups. It is therefore necessary to select the acylation conditions so that they proceed to the desired degree throughout the polymer volume of the carrier material as evenly as possible. This objective benefits from ensuring good swelling of the starting polymer during acylation, either in excess of the acylating agent or by the addition of an inert solvent swelling styrenic polymers such as 1,2-dichloroethane. In the subsequent concentration sulfonation, the strongly acidic hydrophilic groups are then introduced primarily at the non-acylated sites and the bulk of the acylated aromatic nuclei of the polymeric carrier will remain unsulfonated. The resulting polymer has a lower exchange capacity than conventional strong acidic ion exchangers used as catalysts. Under conditions where there is a large excess of polar constituents in the reaction mixture, it exhibits lower catalytic activity than conventionally prepared ion exchanger in the same starting polymer, but in an environment with low (and often technologically preferred) concentration of polar constituents invention significantly higher.

DETAILED DESCRIPTION OF THE INVENTION

Example 1

10 g of styrene-divinylbenzene copolymer containing 2% divinylbenzene were poured over 100 ml of acetyl chloride and allowed to swell overnight. The next day, aluminum chloride (alternatively 5 or 7.5 g) was added portionwise to the mixture while stirring, and the contents of the flask were heated at reflux temperature of acetyl chloride (51-52 ° C) for 3 hours. After cooling, the reaction was quenched by the addition of 50 ml of water, the polymer was transferred to the column and washed first with a 1: 1 mixture of hydrochloric acid and dioxane followed by a 1: 1 mixture of deionized water and dioxane until loss of reaction to chlorides. ₃ ). Finally, the polymer was washed with methanol and dried. After the reaction, the weight of the polymer increased by 20.7%, which corresponds to the acylation of approximately 50% of the aromatic nuclei of the polymer.

Example 2 g of a styrene-divinylbenzene copolymer containing 2% divinylbenzene were poured over 50 ml

1,2-dichloroethane and 50 ml of butyryl chloride are allowed to swell overnight. The next day, aluminum chloride (alternatively 5 or 7.5 g) was added portionwise to the mixture while stirring, under reflux.

The flask contents were then heated at the boiling point of the mixture (85-90 ° C) for 3 hours. After cooling, the reaction was quenched by the addition of 50 ml of water, the polymer was transferred to the column and washed first with a 1: 1 mixture of hydrochloric acid and then a 1: 1 mixture of deionized water until the reaction to chloride disappeared (AgNO ₃ solution added). . Finally, the polymer was washed with methanol and dried. After the reaction, the weight of the polymer increased by 36.7%, corresponding to the acylation of approximately 50% of the aromatic nuclei of the polymer.

Example 3 g of styrene-divinylbenzene copolymer containing 2% divinylbenzene were poured over 50 ml

1,2-dichloroethane and 50 ml octanoyl chloride and allowed to swell overnight. The next day, aluminum chloride (alternatively 5 or 7.5 g) was added portionwise to the mixture while stirring, and the contents of the flask were heated to reflux (85-90 ° C) for 3 hours. After cooling, the reaction was quenched by the addition of 50 ml of water, the polymer was transferred to the column and washed first with a 1: 1 mixture of hydrochloric acid and dioxane and then with a 1: 1 mixture of deionized water until the reaction to chloride disappeared. AgNCl 3). Finally, the polymer was washed with methanol and dried. After the reaction, the weight of the polymer increased by 36.7%, corresponding to the acylation of approximately 50% of the aromatic nuclei of the polymer.

Example 4

The sulfonation of all the acylated polymers prepared by the procedures described in Examples 1 to 32 and the comparative non-acylated polymer was carried out as follows: 10 g of polymer was swelled overnight in excess of 1,2-dichloroethane. The next day the excess aspirated Solvents and swollen polymer was poured 40 ml of 96% HsSO _fourth The mixture was then refluxed with 1,2-dichloroethane (84 ° C) for 3 hours with stirring.

After cooling, the contents of the reaction vessel were diluted with several portions of successively dilute sulfuric acid 30 and then washed with deionized water until neutral. The resulting catalyst was then dried overnight at 110 ° C and stored in a desiccator over phosphorus pentoxide. Overview of catalyst preparation conditions.

Table 1

Overview of the preparation conditions and the resulting exchange capacity of the catalysts prepared by the procedures described in Examples 1-4.

Catalyst 0 AND (B) C D E F Conditions acylation Acetyl chloride (ml) - 100 ALIGN! 100 ALIGN! - - Butyryl chloride (ml) - - - 50 50 Octanoyl chloride (ml) - - - - - 50 50 AlCla (g) - 5 7.5 5 7.5 5 7.5 Dichloroethane (ml) - - - 50 50 50 50 Swap. capacity after sulfonation, meq / g 5.30 4.16 4.03 3.97 3.25 3.54 2.87

Example 5

The activity of the ion exchange catalysts prepared by the procedures described in Examples 1-4 was tested for the reaction of esterification of stearic acid with methanol in a flow reactor. The tests were carried out with a constant weight of 0.5 g of catalyst. The reaction temperature was 85 ° C and a 5 wt. % stearic acid in edible oil and methanol in a ratio

Corresponding to a methanol concentration of 20 and 5 wt. %. The feed rate of the reaction mixture relative to the catalyst weight (W / F) was chosen to achieve relatively low acid conversions, where the conversion value is more proportional to the catalyst activity. The results of the tests, which included a conventionally prepared, non-acylated catalyst (Catalyst 0) for comparison, are shown in Table 2.

Table 2 Results of catalyst activity tests prepared by the procedures described in Examples 1-4.

W / F (g cat, h) / (kg of oil) Concentration of MeOH. % Stearic acid conversion,% 0 AND (B) C D E F 6.5 20 May 47.1 33.7 24.5 25.8 17.2 50.8 42.3 13 20 May 75.3 60.2 45.7 45.3 30.8 73.2 65.0 6.5 5 3.1 7.4 8.3 10.8 12.7 14.5 17.8 13 5 7.0 11.7 14.2 18.9 25.2 27.7 28.7

Table 3

Catalyst volumes prepared as described in Examples 1 to 4 at different methanol concentrations in the reaction mixture.

Mass concentration % MeOH., Volume catalyst bed, ml / g 0 AND (B) C D E F 20 May 6.2 3.5 3.3 3.1 2.5 4,5 3.6 5 2.7 2.3 2.6 2.6 2.6 2.4 2.5

Methanol concentration 20 wt. % corresponded to saturation to supersaturation of the oil phase with methanol and under these conditions the catalyst was fully saturated with methanol. The conventionally prepared comparative catalyst 0 was significantly swelled at this methanol concentration (Table 3) and its catalytic activity was high (Table 2). By limiting the concentration of polar reagents (methanol) in the reaction mixture the swelling and the activity of conventionally prepared catalyst 0 decreased sharply. In contrast, after decreasing the methanol concentration, the decrease in activity of the catalysts prepared according to the invention was much lower. Compared to conventionally prepared Catalyst 0, the activity of Catalysts A to F prepared using acylation was 3 to 5 times higher at a reduced methanol concentration.

Industrial applicability

The strongly acidic ion exchange catalyst with affinity for lipophilic regents can be used as a catalyst for various chemical processes replacing soluble acids.

Claims (6)

PATENT CLAIMS 1. A strongly acidic ion exchange catalyst with affinity for lipophilic reagents having sulfonated aromatic cores of the polymer backbone, characterized in that 20 to 70% of the aromatic cores of the polymeric backbone of the catalyst comprise acyl groups with a chain 2 to 12 carbon atoms. 2. A process for the preparation of strongly acidic ion exchange catalysts having affinity for lipophilic reagents by sulfonating the aromatic nuclei of the polymer backbone according to claim 1, characterized in that the polymer backbone is exposed to acylating agent at a temperature of from 50 [deg.] C. up to boiling of the acylating agent and for 1 to 4 hours. The process according to claim 2, characterized in that before the acylation is controlled, the acylating agent is allowed to act on the polymer backbone at normal temperature for 1 to 24 hours. Process according to claim 2 or 3, characterized in that it is the starting material Gel or macroreticular copolymers of styrene and technical divinylbenzene containing 1 to 40 moles are used for the polymeric backbone. % divinylbenzene. A process according to claims 2 to 4, characterized in that the acylating agent contains 2 and 12 carbon atoms. 6. A process according to claim 5 wherein the acylating agent is selected from the group of acyl halides.