Dithiol

Example 1

2 g of cyanuric chloride (Sigma Aldrich) and 2.4 g of 1,4-dithiol benzene (TCI) were put into 300 mL of 1,4-dioxane (Samchun Chemicals), the resulting solution was stirred, 10 mL of DIPEA (TCI) was added thereto when the solution was completely transparent, and the resulting solution was stirred at 15° C. for 1 hour. Thereafter, the solution was stirred at 25° C. for 2 hours and at 85° C. for 21 hours and filtered, the filtered product was washed with ethanol, and the washed product was sufficiently dried in an oven at 60° C. The produced polymer is represented by “di-S-POL”.

In order to confirm the structures of the polymer supports di-S-POL and tri-S-POL produced in Synthesis Examples 1 and 2, a CP/MAS ¹³C NMR analysis was performed, and the results thereof are shown in the following FIG. 2. As shown by the data in FIGS. 2A and 2B, respectively, the polymers produced in Synthesis Examples 1 and 2 have structures similar to those of Formulas 3 and 6, respectively.

For the analysis of the physical properties of the polymer support, a differential scanning calorimetry (DSC) analysis was performed, and the results thereof are shown in FIGS. 3A and 3B. As shown in FIGS. 3A and 3B, the polymers produced in Synthesis Examples 1 and 2, respectively, were not cross-linked as in the expected structure, and peaks corresponding to Tm and Tc did not appear.

In order to confirm the thermal stability of the polymer supports, the synthesized polymers were subjected to a thermal gravimetric analysis (TGA) in a hydrogen atmosphere, and the results thereof are shown in FIGS. 4, 9, and 10. More specifically, FIGS. 4A, 4B, 9A, 9B, 10A and 10B are graphical representation of the change in weight of the polymer supports as relates to the temperature in a hydrogen atmosphere, as measured by a thermal gravimetric analyzer. As shown by the results of the thermal gravimetric analysis in FIGS. 4A, 4B, 9A, 9B, 10A and 10B, respectively, the polymers produced in Synthesis Examples 1 to 6 were stable up to about 450° C. in a hydrogen atmosphere.

A process was performed in the same manner as in Example 1, except that in Example 1, a commercially available silica (Aldrich, 236772) was used instead of the polymer support produced in Synthesis Example 1. The produced catalyst is represented by “Pd/SiO₂”.

Example 2

A polymer was synthesized in the same manner as in Synthesis Example 1, except that the polymer was synthesized by putting 2.08 g of 1,3,5-trithiol benzene (TCI) thereinto instead of the 1,4-dithiol benzene. The produced polymer is represented by “tri-S-POL”.

A process was performed in the same manner as in Example 1, except that the polymer support produced in Synthesis Example 2 was used instead of the polymer support produced in Synthesis Example 1.

In order to confirm the state of active metals supported on the polymer supports in Examples 1 and 2, a transmission electron microscope (TEM) analysis was performed, and the TEM images are shown in FIGS. 5A and 5B. As shown in the TEM images of FIGS. 5A and 5B, palladium metal particles with a size of about 4 nm were present while being uniformly dispersed in both the Pd/di-S-POL and Pd/tri-S-POL samples, respectively.

In order to confirm the thermal stability of the polymer support catalysts in Examples 1 and 2, the catalyst having palladium supported on the polymer support was subjected to thermal gravimetric analysis (TGA) in a hydrogen atmosphere, and the results thereof are shown in FIGS. 6A and 6B. More specifically, FIGS. 6A and 6B show the change in weight of the catalyst as relates to the temperature in a hydrogen atmosphere, as measured by a thermal gravimetric analyzer. As shown by the results in FIGS. 6A and 6B, the polymers produced in Synthesis Examples 1 and 2, respectively, were stable up to about 250° C. under a hydrogen atmosphere.

Example 3

A polymer was synthesized in the same manner as in Synthesis Example 1, except that 1,3-dithiol benzene was used instead of the 1,4-dithiol benzene.

A process was performed in the same manner as in Example 1, except that the polymer support produced in Synthesis Example 3 was used instead of the polymer support produced in Synthesis Example 1.

The activities of the supported catalysts produced in the Examples and the Comparative Example were confirmed by the following method.

A hydrogenation reaction of acetylene was performed under conditions of 1 atm, 60° C., and a weight hourly space velocity (WHSV) of 0.021 to 1.25 g_C2H2 g_cat⁻¹h⁻¹ by feeding 0.6 kPa of acetylene, 49.3 kPa of ethylene, and 0.9 kPa of hydrogen- and nitrogen-based gases.

In order to analyze product components in the hydrogenation reaction, the product components were analyzed using gas chromatography. The conversion of a reactant (acetylene) and the selectivity of products (ethylene, ethane, and the like) were calculated by the following Equations 1 and 2:

$\begin{array}{cc}\mathrm{Conversion}\left(\%\right)=\left(\mathrm{the}\mathrm{number}\mathrm{of}\mathrm{moles}\mathrm{of}\mathrm{acetylene}\mathrm{reacted}\right)/\left(\mathrm{the}\mathrm{number}\mathrm{of}\mathrm{moles}\mathrm{of}\mathrm{acetylene}\mathrm{fed}\right)\times 100;& \left[\mathrm{Equation}1\right]\\ \mathrm{Selectivity}\left(\%\right)=\left(\mathrm{the}\mathrm{number}\mathrm{of}\mathrm{moles}\mathrm{of}\mathrm{product}\mathrm{produced}\right)/\left(\mathrm{the}\mathrm{number}\mathrm{of}\mathrm{moles}\mathrm{of}\mathrm{acetylene}\mathrm{reacted}\right)\times 100.& \left[\mathrm{Equation}2\right]\end{array}$

The acetylene hydrogenation reaction results using the catalysts produced in Examples 1 and 2 are shown in the following Table 1 and FIGS. 7 and 8. More specifically, FIG. 7 is a graphical representation of the selectivity of ethylene as relates to the value of the acetylene conversion, and FIG. 8 is a graphical representation of the conversion of acetylene as relates to the value of 1/WHSV.

Analysis devices and analysis conditions applied in the present application are as follows.

1) Cross polarization magic-angle spinning ¹³C nuclear magnetic resonance (CP/MAS ¹³C NMR):

Used equipment: Avance III HD (400 MHz) with wide bore 9.4 T magnet (Bruker).

Analysis method: Larmor frequency of 100.66 MHz, repetition delay time of 3 seconds. Chemical shifts were reported in ppm relative to tetramethyl silane (0 ppm).

2) Differential scanning calorimetry (DSC):

Used equipment: DSC131 evo (Setaram).

Analysis method: After a sample was placed on an alumina pan, the conversion was measured by regulating the temperature at a rate of 5 K/min from 313 K to 593 K.

3) Transmission electron microscope (TEM):

Used equipment: JEM-2100F (JEOL) at 200 kV.

4) Thermal gravimetric analysis (TGA):

Used equipment: TGA N-1000 (Scinco).

Analysis method: the conversion was measured by increasing the temperature at 5 K/min from 323 K to 1,025 K. 5) Gas chromatography (GC):

Used equipment: YL6500 (Youngin).

Analysis method: on-line GC, equipped with flame ionized detector (FID), GS-GasPro (Agilent) column was used.

As shown by the Results in Table 1 and FIGS. 7 and 8, that the catalyst (Pd/di-S-POL) of Example 1, the catalyst (Pd-tri-S-POL) of Example 2, and the catalysts of Examples 3 to 6, which are catalysts for a hydrogenation reaction according to exemplary embodiments of the present application, exhibit high ethylene selectivity even at high conversion and have better ethylene selectivity than the catalyst (Pd/SiO₂) of Comparative Example 1 at the same hourly space velocity.

From the experimental results using the polymer support comprising the repeating unit represented by any one of Formulae 3 to 8, similar effects can be obtained even when a functional group such as another alkyl group and aryl group having a similar action principle is additionally bonded to a repeating unit represented by Formula 1 or 2.

Therefore, according to an exemplary embodiment of the present application, a polymer support comprising the repeating unit represented by Formula 1 or 2 can be applied as a support of a catalyst for a hydrogenation reaction.

Further, according to an exemplary embodiment of the present application, the catalyst comprising the polymer support is characterized by having excellent stability in the reaction temperature range of the hydrogenation reaction and being able to improve the selectivity for the product of the hydrogenation reaction.

Example 4

A polymer was synthesized in the same manner as in Synthesis Example 1, except that 1,2-dithiol benzene was used instead of the 1,4-dithiol benzene.

A process was performed in the same manner as in Example 1, except that the polymer support produced in Synthesis Example 4 was used instead of the polymer support produced in Synthesis Example 1.

Example 5

A polymer was synthesized in the same manner as in Synthesis Example 1, except that 2.6 g of 4-methyl-1,2-dithiol benzene was used instead of the 1,4-dithiol benzene.

A process was performed in the same manner as in Example 1, except that the polymer support produced in Synthesis Example 5 was used instead of the polymer support produced in Synthesis Example 1.

Example 6

A polymer was synthesized in the same manner as in Synthesis Example 1, except that 3.3 g of 4-tert-butyl-1,2-dithiol benzene was used instead of the 1,4-dithiol benzene.

A process was performed in the same manner as in Example 1, except that the polymer support produced in Synthesis Example 6 was used instead of the polymer support produced in Synthesis Example 1.