KR20020061434A - Modified nickel-alumina catalyst for selective hydrogenation of diolefins and preparation method thereof - Google Patents

Abstract

PURPOSE: The modified nickel-alumina catalyst for selective hydrogenation of diolefins of the present invention is manufactured by surface modifying gamma-alumina support with one element selected from zirconium, lanthanum and tin, and then it is further supported by nickel. CONSTITUTION: In a modified nickel-alumina catalyst for selective hydrogenation of diolefins that is manufactured by surface modifying gamma-alumina support with one element selected from zirconium, lanthanum and tin, and then it is further supported by nickel, the present invention is characterized in that gamma-alumina support is supported by one element selected from zirconium, lanthanum and tin in an amount of 0.2 to 10 wt.% and nickel in an amount of 0.5 to 10 wt.%, based on the weight of the gamma-alumina support. Before the modified nickel-alumina catalyst is used to convert diolefins to corresponding mono olefins through selective hydrogenation reaction, the modified nickel-alumina catalyst should undergo reduction stage at 400-500deg.C and pretreatment at 300-450deg.C in H2S gas atmosphere.

Description

Modified Nickel-Alumina catalyst for selective hydrogenation of diolefins and preparation method

The present invention relates to a modified nickel-alumina-based catalyst for the selective hydrogenation of diolefin compounds and a method for preparing the same, and more particularly, to a gamma-alumina carrier whose surface is modified with one component selected from zirconium, lanthanum and tin. It relates to a modified nickel-alumina-based catalyst which can be usefully used for selective hydrogenation of aliphatic di-olefin compounds as a catalyst supporting nickel on a phase, and a method for producing the same.

The selective hydrogenation process may be important when the compound to be hydrogenated is desired to control the product at a desired stage. This selective hydrogenation process aims to improve the product quality by removing diene-compound having two double bonds or acetylene hydrocarbon having triple bond in the petrochemical and refining industries as a by-product of the final product. It is very important. In this case, when the diene-compound or acetylene hydrocarbon is included in the product, a side reaction occurs in the next step of the catalytic conversion to reduce the purity or yield of the final product or to prevent the process operation due to the formation of a polymer. May cause.

Therefore, the selective hydrogenation process can fundamentally improve this problem to reduce the load of the separation problem and to be important in improving the purity and yield of the product.

In addition, the mono-olefin produced by the paraffin dehydrogenation process is very important in the petrochemical and oil refining industry. In other words, linear mono-olefin mixtures having a range of 9 to 15 carbon atoms are used to prepare a linear alkylbenzene mixture through an alkylation process with benzene, and such linear alkylbenzenes are used as surfactants and biodegradable detergent raw materials. It is a very important chemical.

However, mono-olefins produced by the dehydrogenation process of linear paraffins inevitably produce di-olefins as side reactants to reduce mono-olefin yields, thereby reducing economics, and furthermore, the presence of di-olefins into linear alkylbenzenes. Not only does it generate a diphenyl compound having a high boiling point as a byproduct in the alkylation process but also unnecessarily increases the consumption of the acid catalyst of the alkylation process. In addition, since the high boiling point diphenyl compound lowers the purity of the linear alkylbenzene used as a soft detergent material and inhibits physical properties, it should be removed in the di-olefin step before the diphenyl compound is produced. There are two methods for removing such di-olefins. One is separation by distillation and the other is by reaction. However, since mono-olefin and di-olefin have similar boiling points, separation by distillation is not so easy. Therefore, the selective conversion of di-olefins to mono-olefin hydrocarbons not only solves the separation problem but also contributes to the improvement of mono-olefin yield, and thus can be expected to have an effect of improving the economics of the process.

Conventional catalyst components used for the selective hydrogenation of di-olefins include nickel, platinum, and palladium. Among them, palladium and platinum are widely used because of their high selectivity for hydrogenation. Industrially preferred.

However, the nickel-supported catalysts used up to now have excellent activity on the hydrogenation reaction, but have almost no selectivity, thus reducing not only the double bond of the di-olefin but also the unsaturated double bond of the mono-olefin without further treatment. Furnace is difficult to apply to the selective hydrogenation reaction.

As a conventional method for solving such a problem, a method of preparing a supported catalyst and reducing it, followed by pretreatment with a sulfur compound such as hydrogen disulfide or thiophene, greatly reduces the activity of nickel, and is generally used. That is, sulfur-treated Ni-Al ₂ O ₃ has been proposed by various groups as a catalyst for the selective hydrogenation of various types of di-olefins (US Pat. No. 3,234,298, US Pat. No. 3,472,763, US Pat. No. 3,919,341). , US Pat. No. 4,695,560]. Representatively, U.S. Patent No. 4,695,560, proposed by UOP, proposes a sulfur-treated Ni-Al ₂ O ₃ catalyst as a selective hydrogenation catalyst for C10-13 linear di-olefin hydrocarbons, wherein the catalyst is 0.05-. It contains a sulfur component in the range of 1.5% by weight and 1.0 to 25% by weight of nickel, and has a pore volume of 1.4 to 2.5 cc / g, a surface area of 150 m 2 / g or more and a pore diameter of 150 mm or less, which is 25% or less of the total pore volume. The pore diameter of at least 500 mm 3 has at least 60% of the total pore volume.

In addition, Shell Oil (US Pat. No. 4,078,011) proposes a nickel catalyst having a sulfide of aluminum as a selective hydrogenation catalyst instead of an alumina carrier, and in the case of the catalyst, three to six di-olefin hydrocarbons are used. There is a characteristic applied to selective hydrogenation.

As such, in many cases, a nickel-alumina-based catalyst is used in the di-olefin selective hydrogenation process, and the catalyst is charged in the reactor to increase the selectivity of the catalyst, and then sulfur-treated before the reaction to significantly reduce the activity to proceed with the reaction. I'm using.

However, in spite of such sulfur treatment, the mono-olefin selectivity of the nickel-alumina catalyst is only 50% or less, and thus the catalyst improvement for improving the catalyst selectivity is required.

As described above, since the catalyst for selective hydrogenation of the conventional di-olefin compound still lacks catalyst selectivity, there is an urgent need for development of a new selective hydrogenation catalyst having the above problems.

The present invention modifies the surface of the carrier by adding one component of zirconium, lanthanum and tin to the gamma-alumina carrier of the conventional nickel-alumina catalyst to improve the above problems, thereby weakening the activity of the excessively strong nickel and improving selectivity. It is an object to provide a modified nickel-alumina-based catalyst.

In the nickel-alumina catalyst for selective hydrogenation of di-olefin compounds contained in a hydrocarbon mixture, nickel is supported on a gamma-alumina carrier whose surface is modified with one of zirconium, lanthanum and tin. It is characterized by a modified nickel-alumina based catalyst.

The present invention provides a method for preparing a nickel-alumina catalyst for the selective hydrogenation of di-olefin compounds contained in a hydrocarbon mixture, wherein a component selected from zirconium, lanthanum and tin is dissolved in distilled water to add a gamma-alumina carrier to wet it. Preparing a modified gamma-alumina carrier by impregnation and supporting the modified gamma-alumina carrier in distilled water in which nickel nitrate is dissolved in a modified gamma-alumina carrier by wet impregnation or precipitation. It is another feature of the method for producing a modified nickel-alumina-based catalyst consisting of.

The present invention is further characterized by a method of selectively hydrogenating a di-olefin compound contained in a hydrocarbon mixture using the modified nickel-alumina-based catalyst.

The present invention will be described in more detail as follows.

The modified nickel-alumina catalyst according to the present invention is a mono-olefin by selectively hydrogenating a di-olefin compound to a mono-olefin compound having the same carbon number in a hydrocarbon mixture having 8 to 15 carbon atoms containing one or two double bonds. It relates to a modified nickel-alumina-based catalyst capable of improving the yield of -olefin.

In the present invention, by impregnating, sedimentation deposition, sol-gel method, co-precipitation method, chemical vapor deposition method, ion exchange method, etc., the nickel is supported on a gamma-alumina carrier whose surface is modified with one component selected from zirconium, lanthanum and tin. To prepare a nickel-alumina-based catalyst.

Looking at such a modified nickel-alumina-based catalyst according to the manufacturing process in detail as follows.

The modified nickel-alumina-based catalyst undergoes two steps of preparation, namely, modification of the gamma-alumina carrier and nickel loading of the modified gamma-alumina.

First, gamma-qualified process of the alumina support is a zirconium nitrate as the zirconium source ^{_{(. ZrO (NO 3) 2}} xH 2 O), lanthanum nitrate as the lanthanum source ^{_{(. La (NO 3) 3}} 6H 2 O), tin source dichloride tin salts ^(. SnCl ₂ 2H ₂ O), create a component of an aqueous solution dissolved in distilled water, selected from the group consisting of gamma-gamma drying an aqueous solution of an appropriate amount according to the concentration of 0.2 to 10% by weight based on the alumina carrier-alumina carrier (non- Surface area 210 m ² / g, pore volume 0.75 mL / g) and prepared by wet impregnation method. The material thus obtained is dried in an oven at 110 ° C. for 4-6 hours and then placed in a kiln for 4 hours at 500 ° C. Then, nickel nitrate _{(Ni (NO 3) 2 6H} 2 O.) An aqueous solution of gamma dissolved in distilled water - is supported on the alumina-based on the alumina support of gamma qualified by the wet impregnation method according to the concentration of 0.5 to 10% by weight Or supported by gamma-alumina modified by precipitation using ammonia water. The material thus obtained is dried in an oven at 110 ° C. for 4 to 6 hours, then placed in a kiln, and calcined at 500 to 700 ° C. for 4 hours to finally prepare a modified nickel-alumina catalyst.

Meanwhile, the selective hydrogenation process using the modified nickel-alumina-based catalyst prepared by the method described above is as follows. The selective hydrogenation activity is measured through the hydrogenation process.

In the measurement of the catalytic activity of the present invention, a typical fixed bed catalytic reactor manufactured in the laboratory is used. Before the selective hydrogenation catalyst is added to the reactor, a pretreatment is performed, i.e., 1 g of the catalyst prepared above is charged into a 3/8 inch stainless steel reactor to apply the catalyst prepared above to the selective hydrogenation reaction. 5% hydrogen with a flow rate of 50 mL per minute was reduced for 1 to 4 hours in the range of 400 to 500 ° C., followed by nitrogen gas containing 1000 ppm of H ₂ S gas for 2 hours in the range of 300 to 450 ° C. per minute. After passing through the catalyst bed at a flow rate of 100 mL, pretreatment is carried out to lower the reaction temperature. In this case, in order to prevent the catalyst powder from sinking to the bottom of the reactor during the reaction, the reactor is fixed by welding a stainless steel filter having pores of 1 μm in the middle of the reactor and then filling the catalyst thereon.

After pretreatment of the catalyst as described above, a liquid reactant consisting of a linear aliphatic hydrocarbon mixture having 8 to 15 carbon atoms, which is adjusted to the reaction temperature to be measured, is quantitatively injected into the reactor using an HPLC pump (ICI LC 1110). The reaction is passed through the catalyst bed for 5 minutes at a volume of 5 ml per minute so as to completely wet the furnace. In this case, the linear aliphatic hydrocarbon mixture having 8 to 15 carbon atoms is obtained by dehydrogenation of linear aliphatic paraffins using a Pt-Sn-based dehydrogenation catalyst, and unreacted linear aliphatic paraffins, mono-olefins and di-olefins. A mixture of a product, an aromatic compound, and the like is used for the reaction, for example, a mixture of 84.5% by weight of paraffin, 10.3% by weight of mono-olefin, 1.2% by weight of di-olefin, and 4.0% by weight of aromatic compound. Can be used for the reaction.

Then, the liquid reactant and hydrogen are passed through the catalyst bed at a constant ratio according to the reaction conditions, and the liquid from the cooler after the reactor is collected in a vial and analyzed for the concentration of hydrocarbon before and after the reaction using HPLC. . At this time, the reaction conditions include a reaction temperature of 80 to 250 ° C., a reaction pressure of 1 to 12 atm, and a liquid hourly space velocity (LHSV) of liquid reactant per hour of 4 to 12 per hour, hydrogen: di- in a linear aliphatic hydrocarbon mixture. Catalyst activity is measured in the range of 1.0-3.0: 1 the ratio of an olefin. The temperature of the reactor is controlled by an electric heater and a programmable thermostat, and the reaction pressure is controlled by a back pressure regulator installed after the reactor. The flow rate of the added hydrogen is controlled by an automatic flow control device (MKS Instrument, Model 247C), and it is difficult to accurately match the flow rate of hydrogen because of the very small amount added to react quantitatively with the reactant di-olefin. Immediately after the automatic flow regulator, hydrogen is periodically injected using an automatic on-off valve called a solenoid valve.

In the present invention, the composition of the hydrocarbon before and after the reaction is analyzed using HPLC with a refractive index detector, in which the column is connected by connecting two silica HPLC columns in series, and the elution solvent of the HPLC is n-hexane. use.

The modified nickel-alumina catalyst according to the present invention as described above can selectively convert di-olefin hydrocarbons from linear aliphatic hydrocarbon mixtures to the same moles of mono-olefin hydrocarbons to convert the hydrogenated compound to the desired step of the product. It may be important for the hydrogenation process to control the selectivity.

Hereinafter, the present invention will be described in more detail based on the following examples, but the present invention is not limited by the examples.

Example 1

The nickel-zirconia-alumina catalyst (Ni-Zr-Al ₂ O ₃ ) used in this example was prepared in a two step process.

Wet impregnation was first used to modify the gamma-alumina carrier. A zirconium source of zirconium nitrate ^{_{(ZrO (NO 3) 2.}} XH 2 O) to an aqueous solution of an appropriate amount such that 4.5 wt% at a concentration of the zirconium metal, create a solution dissolved in distilled water, 1.8 ~ 2.0 mm The dried spherical gamma having a diameter of -Added to an alumina carrier (specific surface area 210 m ² / g, pore volume 0.75 mL / g) and thoroughly mixed, the material thus obtained was dried in an oven at 110 ^o C for 4 to 6 hours and then placed in a baking furnace at 4 ^o 500 ^o C. It was obtained through the calcination process of time. Then prepare a nickel nitrate aqueous solution by an amount corresponding to the pore volume of the alumina support is dissolved in a ^{_{(Ni (NO 3) 2.}} 6H 2 O) of distilled water, and according to a concentration of 4.5% by weight based on the nickel metal to the aqueous solution It was mixed with gamma-alumina modified with zirconium. The material thus obtained was dried in an oven at 110 ^° C. for 4 to 6 hours and then placed in a kiln to finally produce a baking process at 500 ^° C. for 4 hours.

Example 2

A nickel-zirconia-alumina catalyst was prepared by obtaining alumina carrier modified with 2% by weight of zirconia using the same method as in Example 1 and supporting nickel oxide by precipitation-deposition. In the method of supporting nickel oxide, 1M of nickel nitrate aqueous solution was prepared, and then stired vigorously at 60 ° C. for 6 hours in a ratio required for 500 mL of 1M ZrCl ₄ aqueous solution obtained by recrystallization, followed by adding 29.8% ammonia water (Fisher Scientific). After the precipitate was added until the pH was 10, the precipitate was filtered, washed with 5% dilute ammonia water until no more chlorine ions were observed, and then washed with distilled water. The material thus obtained was dried in an oven at 110 ^° C. for 4 to 6 hours and then placed in a kiln to finally produce a baking process at 500 ^° C. for 4 hours. The amount of nickel supported at this time was 3.0 wt% based on the nickel metal.

Example 3

A nickel-zirconia-alumina catalyst was prepared in the same manner as in Example 1 except that the content of zirconium was 6.0 wt% and the amount of nickel was 6.0 wt%.

Example 4

It was prepared in the same manner as in Example 1 except that lanthanum was used instead of zirconium as a component to modify the gamma-alumina carrier, and the content of lanthanum was 2.0% by weight and the amount of nickel was 6.0% by weight of nickel-lanthanum-alumina (Ni -La-Al ₂ O ₃ ) catalyst was prepared.

Example 5

Prepared in the same manner as in Example 1 except that tin was used instead of zirconium to modify the gamma-alumina carrier, and the tin content was 3.0% by weight and the nickel loading was 6.0% by weight of nickel-tin-alumina (Ni -Sn-Al ₂ O ₃ ) catalyst was prepared.

Comparative Example 1

A nickel-alumina-based catalyst containing 5% by weight of nickel was prepared by impregnation to compare with the selective hydrogenation activity of the modified nickel-alumina-based catalyst obtained in the examples. As the carrier, the same gamma-alumina as in Example 1 was used. In the preparation process, 1 mol of nickel nitrate aqueous solution was added to 20 g of the spherical gamma-alumina support so as to meet the supporting amount of 4.5 wt% and stirred at 50 ° C. for 6 hours. Then, a flask containing a solution was connected to a rotary vacuum evaporator, and the water was evaporated while rotating at a temperature of 100 torr and a temperature of 80 ° C. The catalyst precursor powder having evaporated water was put in a drying oven, dried at 100 ° C. for 12 hours, and then put in a kiln, and calcined at 650 ° C. for 4 hours in air to prepare a nickel-gamma-alumina (Ni-γ-Al ₂ O ₃ ) catalyst. Got it.

Experimental Example 1

The selective hydrogenation activity of the catalysts obtained in Examples 1 to 5 and Comparative Example 1 was measured by the following method, and the results are shown in Table 1 below.

A typical fixed bed catalytic reactor manufactured in the laboratory was used to measure the catalytic activity. Before adding the selective hydrogenation catalyst to the reactor, the pretreatment process is carried out with a 3/8 inch with electric heater, programmable thermostat (HY P-100) and back pressure regulator. 1 g of the catalyst prepared above was charged to a sized stainless steel reactor with 5% hydrogen having a flow rate of 50 mL per minute, reduced for 1 to 4 hours in the range of 400 to 500 ° C., and then again for 2 hours in the range of 300 to 450 ° C. A nitrogen stream containing 1000 ppm H ₂ S gas is passed through the catalyst bed at a flow rate of 100 mL per minute, pretreated, and lowered to the reaction temperature for use in the reaction. At this time, the reactor was fixed by welding a stainless steel filter having pores of 1 μm in the middle of the reactor and filling the catalyst thereon. After pretreatment of the catalyst as described above, a liquid reactant consisting of a linear aliphatic hydrocarbon mixture having a carbon number of 8 to 15, adjusted to the reaction temperature to be measured, is quantitatively injected into the reactor using an HPLC pump (ICI LC 1110). The reaction is passed through the catalyst bed for 5 minutes at a volume of 5 ml per minute so as to completely wet the reaction. In this case, the linear aliphatic hydrocarbon mixture having 8 to 15 carbon atoms is obtained by dehydrogenation of linear aliphatic paraffins using a Pt-Sn-based dehydrogenation catalyst, and unreacted linear aliphatic paraffins, mono-olefins and di-olefins. The product, an aromatic compound, and the like were mixed, and the composition was 84.5 wt% of paraffin, 10.3 wt% of mono-olefin, 1.2 wt% of di-olefin, and 4.0 wt% of aromatic compound. Meanwhile, after wetting the catalyst with the reactant, the liquid reactant and hydrogen are passed through the catalyst layer at a constant ratio according to the reaction conditions, and the liquid from the cooler after the reactor is collected in a vial to collect the hydrocarbon before and after the reaction using HPLC. Analyze the concentration. At this time, in order to compare the selective hydrogenation activity of the catalyst obtained in the Example and the catalyst obtained in the Comparative Example, the reaction temperature is 200 ℃ range, the reaction pressure is 10 atm, the liquid hourly space velocity (LHSV) of the liquid reactant per hour is 6 per hour The catalytic activity was measured under the condition that the ratio of di-olefins in the hydrogen: linear aliphatic hydrocarbon mixture was 1.5: 1. The composition of the hydrocarbon before and after the reaction was analyzed using HPLC (Shimadzu LC-10AD) attached with a refractive index detector (Shimadzu RIS-10A), wherein the column was composed of two silica (Waters, Spherisorb 5 μm) HPLC columns. Were used in series, and the elution solvent of HPLC used n-hexane.

In Table 1 below, the selective hydrogenation activity of the catalysts prepared in Examples 1 to 5 and the catalysts prepared in Comparative Example 1 were compared. Is expressed as an average value.

In Table 1, the Ni-γ-Al ₂ O ₃ catalyst of Comparative Example 1 has a high di-olefin conversion but relatively low selectivity for mono-olefin (42.8%), but modified with zirconium, lanthanum or tin. In the case of the nickel catalyst supported on the gamma-alumina support, the mono-olefin selectivity is greatly increased compared to the Ni-γ-Al ₂ O ₃ catalyst, resulting in a mono-olefin yield of a minimum compared to the Ni-γ-Al ₂ O ₃ catalyst. Results have been improved from 15% up to 29%.

As described above, the modified nickel-alumina-based catalysts useful for the selective hydrogenation of di-olefin compounds contained in the hydrocarbon mixtures of the present invention are simple forms of N i- which are widely used in petrochemical processes in the sulfur treatment. Compared to the γ-Al ₂ O ₃ catalyst it can improve the mono-olefin selectivity suggests that it can be utilized as a way to greatly alleviate the separation problem by the by-product treatment and increase the yield of the product.

Claims (6)

Nickel-alumina catalyst for selective hydrogenation of di-olefin compounds contained in a hydrocarbon mixture, characterized in that the nickel is supported on a gamma-alumina carrier whose surface is modified with one of zirconium, lanthanum and tin. Modified nickel-alumina-based catalyst. The modified nickel-alumina catalyst according to claim 1, wherein the zirconium, lanthanum and tin are contained in an amount of 0.2 to 10 wt% based on gamma-alumina. The modified nickel-alumina catalyst according to claim 1, wherein the nickel is contained in an amount of 0.5 to 10 wt% based on gamma-alumina. In the method for producing a nickel-alumina catalyst for the selective hydrogenation of the di-olefin compound contained in the hydrocarbon mixture, Dissolving one component selected from zirconium, lanthanum and tin in distilled water to prepare a gamma-alumina carrier modified by wet impregnation by adding a gamma-alumina carrier; and Supporting the modified gamma-alumina carrier in the modified gamma-alumina carrier by wet impregnation or precipitation in distilled water in which nickel nitrate was dissolved; Method for producing a modified nickel-alumina catalyst, characterized in that consisting of. A process for selectively converting di-olefin hydrocarbons into mono-olefin hydrocarbons having the same carbon number on the modified nickel-alumina-based catalyst according to claim 1 is carried out. The method of claim 5, wherein the selective hydrogenation of the di-olefin compound is carried out under a condition that the modified nickel-alumina catalyst is subjected to a pretreatment step of reducing at 400 ~ 500 ℃, H ₂ S gas at 300 ~ 450 ℃ Selective hydrogenation method of the di-olefin compound, characterized in that.