Copper aluminum catalyst used for the production of 1,4-butynediol

Abstract

The present invention relates generally to novel catalyst compositions and processes for producing 1,4-butynediol by catalytic ethynylation of formaldehyde, known as the Reppe reaction. The lower copper content of the catalysts of the present invention provides an advantageous combination of improved copper utilization, reduced copper leaching, and enhanced filterability, with minimal to no impact on catalyst activity.

Description

[Technical Field]

[0001] The present invention relates generally to novel catalyst compositions and processes for producing 1,4-butynediol by catalytic ethynylation of formaldehyde, known as the Reppe reaction. The lower copper content of the catalysts of the present invention provides an advantageous combination of improved copper utilization, reduced copper leaching, and enhanced filterability, with minimal to no impact on catalyst activity. [Background technology]

[0002] 1,4-Butynediol (BYD) is an important organic compound intermediate, forming various chemicals and derivatives. In recent years, the high growth of its hydrogenation product, 1,4-butanediol (BDO), and its downstream products, namely, gamma-butyrolactone (GBL), tetrahydrofuran (THF), polybutylene terephthalate (PBT), and polyurethane (PU), has increased the demand for 1,4-butynediol. The industrial method for producing 1,4-butynediol is mainly via the coal chemical industry, through the ethynylation reaction of formaldehyde and acetylene. Due to the abundance of coal sources, production via the coal chemical route has unique advantages and very low costs.

[0003] State-of-the-art 1,4-butynediol production in China is carried out via ethynylation in a slurry-phase reactor, which reduces operating pressure and the risk of explosion compared to the high-pressure fixed-bed reactors of the past century. Typically, the catalyst is a micron-sized solid powder containing copper oxide, bismuth oxide, and silicic acid-containing materials. For example, the preparation and application of a copper oxide / bismuth oxide catalyst on a magnesium silicate support using a silica binder are separately disclosed in U.S. Patent Nos. 9,006,129 and 10,537,886. However, one drawback of this type of catalyst is the leaching of silica during the catalytic reaction. The leached silica in the product solution is detrimental to the subsequent nickel-catalyzed hydrogenation of 1,4-butynediol. Generally, silica must be removed from the product solution using an ion exchanger, which usually generates a large amount of wastewater and incurs high treatment costs.

[0004] Chinese Patent Application No. 110876939 discloses a method for preparing an ethynylation catalyst on a silica-free alumina support. The prepared catalyst exhibits significantly lower silica leaching compared to commercial catalysts. However, the copper oxide content in the disclosed examples is relatively higher than that of commercial catalysts to achieve comparable activity. A higher copper oxide content increases the likelihood of copper leaching, leading to a serious accumulation of polymeric species that are inevitably formed during long-term operation, blocking active sites, and increasing the risk of flammability.

[0005] Copper acetylide derived from copper oxide is considered to be the active species for the ethynylation reaction. Reducing the copper content in the catalyst is an attractive approach to lower the operational risk if the catalytic activity can be maintained at a comparable level. The Cu / Bi ratio is also adjusted to simultaneously achieve good catalytic activity and filterability. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] U.S. Patent No. 9,006,129 [Patent Document 2] U.S. Patent No. 10,537,886 [Patent Document 3] Chinese Patent Application No. 110876939 Summary of the Invention [Problem to be solved by the invention]

[0007] It is an object of the present invention to provide a catalyst composition for the Reppe reaction that contains lower amounts of copper species and has improved catalytic activity and filterability compared to commercial catalysts. [Means for solving the problem]

[0008] In one embodiment, a catalyst composition is provided comprising: 5% to 35% by weight Cu, calculated as CuO; 0.1% to 7% by weight Bi, calculated as Bi2O3; and 60% to 95% by weight Al, calculated as Al2O3.

[0009] In another aspect, there is provided a method for producing the above-described catalyst composition, comprising the steps of: 1) precipitating a copper-containing and bismuth-containing aqueous solution onto a particulate support using a precipitating agent; and 2) drying the treated particulate support and calcining it at 300 to 800°C to form the catalyst composition, wherein the particulate support comprises an alumina source.

[0010] In another aspect, there is provided a method of using the above-described catalyst composition for hydrogenation, dehydrogenation, hydrocracking, or ethynylation. [Effects of the Invention]

[0011] The catalyst composition prepared in the present invention with a lower copper content can achieve the same activity as commercial catalysts. Although the copper content is lower, the catalytic activity remains at the same level compared to the alumina support examples disclosed in the prior art, and the catalytic activity of copper oxide is higher. Furthermore, the leaching of Cu in the product solution of the catalyst of the present invention is much lower than that of the prior art. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 shows a plot of the comparative production rate of 1,4-butynediol per gram of catalyst. [Figure 2] FIG. 2 shows a plot of the comparative rate of 1,4-butynediol production per gram of CuO species in the catalyst. [Figure 3] FIG. 3 shows a plot of the comparative filtration rates of samples after intensive attrition in H2O for 24 hours. [Figure 4] FIG. 4 shows the microstructure of the catalyst of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] Before describing some exemplary embodiments of the invention, it is to be understood that the invention is not limited to the detailed structures or method steps set forth in the following description, as the invention may be practiced or carried out in other embodiments and in various ways.

[0014] The following definitions are provided for terms used in this disclosure.

[0015] Throughout this specification, including the claims, the terms "comprising one" or "comprising a" should be understood to be synonymous with the term "comprising at least one" unless otherwise specified, and the terms "between" or "from" should be understood to be inclusive of their limits.

[0016] The words "a", "an" and "the" are used to refer to one or to more than one (i.e. to at least one) of the grammatical object of the article.

[0017] The term "and / or" includes the meanings "and", "or" and all other possible combinations of the elements connected to this term.

[0018] All percentages and ratios are by weight unless otherwise specified.

[0019] Thus, in one aspect of the present invention, there is provided a catalyst composition comprising: Cu, calculated as CuO, in an amount of 5% to 35%, preferably 10% to 30%, more preferably 15% to 30%, and most preferably 20 to 30%, including 25 to 28% by weight; Bi, calculated as Bi2O3, in an amount of 0.1% to 7%, preferably 0.4, 1.0, 1.5, 2.0, 2.5, 3.0, and 3.5%, by weight; and Al, calculated as Al2O3, in an amount of 60% to 95%, preferably 70% to 90%, including 75, 80, and 85%, by weight.

[0020] In one or more embodiments, the molar ratio of Cu to Bi is 55 to 300:1, preferably 80 to 200:1.

[0021] In one or more embodiments, Al2O3 has a D of 0.1 to 20 μm, preferably 0.2 to 15 μm. 50 It has.

[0022] As described herein, "D 50 " has the usual meaning of median diameter, referring to the point at which the percentage of particles having a diameter smaller than and larger than this value is 50%. Particle size distribution is measured using a laser diffraction particle size analyzer.

[0023] In one or more embodiments, the catalyst composition has a D of 0.5 to 40 μm, preferably 1 to 30 μm. 50 It has.

[0024] Another embodiment includes a method for producing the above-described catalyst composition, comprising the steps of: 1) precipitating an acidic copper-containing aqueous solution onto a particulate support using a precipitating agent; 2) drying the treated particulate support and calcining it at 300 to 800° C. to form a catalyst composition; wherein the particulate support comprises alumina.

[0025] The type of alkaline aqueous solution used as the precipitating agent is not particularly limited, but inorganic alkalis such as aqueous solutions of sodium hydroxide, potassium hydroxide, and ammonium hydroxide, as well as mixtures thereof, are commonly used.

[0026] As used herein, the term "mixture" or "combination" means, but is not limited to, a combination of any physical or chemical form, such as a blend, solution, suspension, alloy, composite, etc.

[0027] With regard to the copper source, typical copper sources may include, but are not limited to, copper acetate, copper chloride, copper phosphate, copper pyrophosphate, copper nitrate, copper ammonium sulfate, copper albuminate, copper sulfate, copper gluconate, copper lactate, copper saccharinate, copper fructoate, copper dextrinate, and mixtures thereof.

[0028] With regard to the bismuth source, typical bismuth sources may include, but are not limited to, bismuth chloride, bismuth oxychloride, bismuth bromide, bismuth silicate, bismuth hydroxide, bismuth trioxide, bismuth nitrate, bismuth subnitrate, bismuth oxycarbonate, and mixtures thereof.

[0029] Typical aluminas used herein can be alpha-alumina, beta-alumina, gamma-alumina and mixtures thereof.

[0030] Other embodiments include methods of using the above-described catalyst compositions for hydrogenation, dehydrogenation, hydrocracking, or ethynylation.

[0031] Various embodiments are described below, and it should be noted that the specific embodiments are not intended as exhaustive or as limitations on the broader aspects discussed herein.

[0032] Catalyst preparation The particulate alumina support is first added to water in a precipitation vessel. The acidic solution is composed of a mixture of copper-containing salt and bismuth-containing salt in a separate vessel. The basic solution is composed of sodium hydroxide in a separate vessel. The temperature of the solution in the precipitation vessel is set to the precipitation temperature and maintained constant throughout the precipitation process, anywhere from about 40°C to about 90°C. The acidic mixture and sodium hydroxide solution are simultaneously added to the vessel containing the water and particulate support. Precipitation is carried out at a constant pH of about 7 to about 11. During precipitation, the flow of the acidic solution is maintained constant, while the flow of the NaOH solution is adjusted to maintain a constant pH for the precipitation. The precipitation time can be anywhere from 15 minutes to 120 minutes. Typically, the time is about 30 minutes to about 60 minutes. After the precipitation process, the precipitate can be aged for a short period of time, from about 15 minutes to about 120 minutes. The precipitate is then filtered, washed, and dried. The dried material is calcined in air. The firing temperature can vary between about 300°C and about 800°C, including 400, 500, 600, and 700°C.

[0033] Catalytic performance testing of catalysts Using the same test conditions as in U.S. Pat. No. 9,006,129, an activated catalyst is preferably produced by introducing acetylene into the formaldehyde-catalyst reaction medium. In a first reactor, the calcined catalyst is mixed with an aqueous formaldehyde solution. The pH of the aqueous medium is adjusted to a range of 7.0 to 10.0, preferably 8.0. pH control is necessary to suppress the formation of formic acid, which reacts with copper compounds and increases copper loss due to leaching into the solution. Catalyst activation is carried out after introducing an acetylene flow and heating the reactor from room temperature to about 80°C. The activation process typically takes 5 hours.

[0034] The slurry is then removed, centrifuged, and decanted, leaving the wet catalyst for activity testing. In a second reactor, a specific amount of the wet catalyst is mixed with an aqueous formaldehyde solution. An acetylene stream is then introduced at a partial pressure, typically 0.5 to 1.9 atmospheres, preferably 1.0 atmospheres. The catalyst is present in an amount of about 1 to 20 parts by weight per 100 parts by weight of the aqueous formaldehyde medium. The reactor is heated from room temperature to about 80°C. The reaction process typically takes 5 hours, and the pH of the aqueous medium after the reaction is about 5.0. The product mixture is analyzed by gas chromatography to quantify butynediol (the main product) and propargyl alcohol (a product intermediate) to determine the activity of the catalyst.

[0035] Catalyst filterability test In the in-plant ethynylation process, filtration is used to separate the spent catalyst and reaction products. In this case, the spent catalyst is recycled, mixed with fresh catalyst, and fed back into the reactor. Therefore, the filtration rate of the spent catalyst is important for the recycling efficiency. The filtration rate is tested against the catalyst after attrition: about 4 g of fresh catalyst is added to 40 mL of DI H2O and stirred at room temperature for a sufficiently long time. The slurry is then filtered, the time used for filtration is recorded, and the filtration rate is calculated accordingly.

[0036] The present invention is particularly described and illustrated by the following examples, which should not be considered limiting but are merely exemplary of the invention, as well as the appended claims, in which all parts and percentages are by weight unless otherwise specified. [Example]

[0037] Example 1 Average particle size D of 5 μm 50 The α-alumina support having the formula (I) was added to water to obtain a 37% by weight slurry. 117.3 g of a solution of copper nitrate (containing 15.5% by weight Cu) and bismuth nitrate (Cu / Bi molar ratio 95 / 1) was precipitated onto the particulate support using 15% by weight aqueous sodium hydroxide. After the precipitation step, the precipitate was aged at 35°C for 10 minutes. The precipitate was then filtered and dried. The catalyst was obtained after calcination at 450°C, and its composition is shown in Table 1.

[0038] Example 2 Average particle size D of 5 μm 50 The α-alumina support having the formula (I) was added to water to obtain a 37% by weight slurry. 117.3 g of a solution of copper nitrate (containing 15.5% by weight Cu) and bismuth nitrate (Cu / Bi molar ratio 190 / 1) was precipitated onto the particulate support using a 15% by weight aqueous sodium hydroxide solution. After the precipitation process, the precipitate was aged at 35°C for 10 minutes. The precipitate was then filtered and dried. The catalyst was obtained after calcination at 450°C, and its composition is shown in Table 1.

[0039] Example 3 Average particle size D of 5 μm 50 The α-alumina support having the formula (I) was added to water to obtain a 37% by weight slurry. 55.4 g of a solution of copper nitrate (containing 15.5% by weight Cu) and bismuth nitrate (Cu / Bi molar ratio 190 / 1) was precipitated onto the particulate support using a 15% by weight aqueous sodium hydroxide solution. After the precipitation step, the precipitate was aged at 35°C for 10 minutes. The precipitate was then filtered and dried. The catalyst was obtained after calcination at 450°C, and its composition is shown in Table 1.

[0040] Example 4 Average particle size D of 5 μm 50 The α-alumina support having the formula (I) was added to water to obtain a 37% by weight slurry. 55.4 g of a solution of copper nitrate (containing 15.5% by weight Cu) and bismuth nitrate (Cu / Bi molar ratio 48 / 1) was precipitated onto the particulate support using 15% by weight aqueous sodium hydroxide. After the precipitation process, the precipitate was aged at 35°C for 10 minutes. The precipitate was then filtered and dried. The catalyst was obtained after calcination at 450°C, and its composition is shown in Table 1.

[0041] Example 5 Average particle size D of 14 μm 50 The α-alumina support having the formula (I) was added to water to obtain a 37% by weight slurry. 117.3 g of a solution of copper nitrate (containing 15.5% by weight Cu) and bismuth nitrate (Cu / Bi molar ratio 190 / 1) was precipitated onto the particulate support using a 15% by weight aqueous sodium hydroxide solution. After the precipitation process, the precipitate was aged at 35°C for 10 minutes. The precipitate was then filtered and dried. The catalyst was obtained after calcination at 450°C, and its composition is shown in Table 1.

[0042] Comparative Example 1 Average particle size D of 5 μm 50 The α-alumina support having the formula (I) was added to water to obtain a 26% by weight slurry. 117.3 g of a solution of copper nitrate (containing 15.5% by weight Cu) and bismuth nitrate (Cu / Bi molar ratio 48 / 1) was precipitated onto the particulate support using a 15% by weight aqueous sodium hydroxide solution. After the precipitation process, the precipitate was aged at 35°C for 10 minutes. The precipitate was then filtered and dried. The catalyst was obtained after calcination at 450°C, and its composition is shown in Table 1.

[0043] Comparative Example 2 Average particle size D of 15 μm 50The α-alumina support having the formula (I) was added to 200 mL of water to obtain a slurry, which was then heated to 60°C. 500 mL of a 1 mol / L copper nitrate solution containing 10 g / L bismuth nitrate was prepared. Using a peristaltic pump, 50 mL of the Cu / Bi nitrate solution was added to the support slurry and stirred for 10 minutes. Then, 1 mol / L sodium carbonate solution was added to the slurry to adjust the pH of the slurry to 7.0. Another 50 mL of the Cu / Bi nitrate solution was added to the support slurry and stirred for 10 minutes. Then, 1 mol / L sodium carbonate solution was added to the slurry to adjust the pH of the slurry to 7.0 again. The above procedure was repeated until all 500 mL of the Cu / Bi nitrate solution had been added. The precipitate was then filtered, washed, and dried. The catalyst was obtained after calcination at 400°C for 4 hours, and its composition is shown in Table 1.

[0044] Table 1 shows the catalyst components in terms of CuO, Bi2O3, and Al2O3, as well as the molar ratio of Cu / Bi for Examples 1-5 and Comparatives 1 and 2.

[0045] [Table 1]

[0046] The catalytic test was carried out in two steps. First, the catalyst was activated to form activated copper acetylide on the catalyst surface. It was then transferred to a reactor. The detailed procedure is as follows: Activation was carried out in a reactor containing 100 mL of formalin (a 37% by weight aqueous formaldehyde solution). 1.5 M sodium hydroxide solution was added to the formalin to adjust the initial pH to approximately 7.5-9.0, and then 15 g of catalyst was added to the pH-adjusted formalin. The reactor was inactivated by purging with nitrogen, and then the gas flow was changed to 80 mL / min of acetylene. Stirring was started, and heating to 80 °C was initiated with online control of the pH at approximately 8.0 via NaOH solution. The reaction was maintained for 5 hours. The reactor was then cooled to room temperature under acetylene gas flow. For deactivation, nitrogen was purged into the reactor, and the slurry was discharged, centrifuged, and decanted, leaving the wet catalyst for activity testing. 0.8 g of catalyst (dry basis) was added to the reactor along with an aqueous formaldehyde solution. Similarly, the initial pH of the formalin was adjusted to 8.0 with sodium hydroxide solution. The acetylene flow rate was maintained constant at 50 mL / min, and the reaction temperature was 80°C. After 5 hours, the reactor was cooled under a gas stream of acetylene, followed by a nitrogen purge for deactivation. The slurry was discharged and centrifuged. The product mixture was analyzed by gas chromatography to quantify butynediol and propargyl alcohol. The amount of formaldehyde remaining in the product was determined using the sodium sulfite titration method. The activity of the catalyst was then evaluated by the butynediol production rate, calculated based on a 300-minute reaction time and a catalyst mass of 0.8 g. Similar catalytic tests were carried out for Examples 2, 3, 5 and Comparative Example 2 with a longer reaction time of 40 hours. The copper content in the product solution was then measured, and the results are shown in Table 2.

[0047] Filterability tests were performed by simulating the attrition of the catalyst in solution. Approximately 4 g of fresh catalyst was added to approximately 40 mL of DI H2O. Agitation was initiated at a constant speed of 250 rpm and maintained at room temperature for 24 hours each. The slurry was then filtered, the time used for filtration was recorded, and the corresponding filtration rate in mL / min was calculated.

[0048] A comparison of catalytic activity per gram of catalyst and per gram of CuO for the Examples and Comparative Examples is shown in Figures 1 and 2. The Examples with lower Cu content and higher Cu / Bi ratios have similar production rates of 1,4-butynediol per gram of catalyst but higher CuO catalytic activity compared to the Comparative Examples, indicating a higher utilization efficiency of the active species of the alumina-supported CuO / Bi2O3 catalyst.

[0049] The lower Cu content of the catalyst of the present invention reduces the possibility of Cu leaching. As shown in Table 2, after 40 hours of reaction time, the Cu leached into the product solution is reduced for the catalyst of the present invention compared to the prior art sample.

[0050] [Table 2]

[0051] The filterability comparison for the Examples and Comparative Examples is shown in Table 3. It shows that less CuO or more alumina support in the catalyst has a positive effect on improving the filterability.

Claims

1. A catalyst composition for catalyzing the reaction of acetylene with formaldehyde to produce 1,4-butynediol, comprising: 5% to 35% by weight of Cu, calculated as CuO; Bi 2 O 3 0.1% to 7% by weight of Bi, calculated as: Al 2 O 3 60% to 95% by weight of Al, calculated as A catalyst composition, wherein the molar ratio of Cu to Bi (Cu:Bi) is 80 to 200:

1.

2. 10. The catalyst composition of claim 1, comprising 10% to 30% by weight of Cu, calculated as CuO.

3. Bi 2 O 3 3. The catalyst composition of claim 1, comprising 0.2 to 4% by weight of Bi, calculated as:

4. Al 2 O 3 4. The catalyst composition according to claim 1, wherein the catalyst composition contains 70% to 90% by weight of Al, calculated as:

5. The Al 2 O 3 D is 0.1 to 20 μm 50 The catalyst composition according to any one of claims 1 to 4, wherein

6. The Al 2 O 3 D of 0.2 to 15 μm 50 5. The catalyst composition of claim 4, wherein

7. D of 0.5 to 40 μm 50 The catalyst composition according to any one of claims 1 to 6, wherein

8. D of 1 to 30 μm 50 8. The catalyst composition of claim 7, wherein

9. A method for producing the catalyst composition of any one of claims 1 to 8, comprising: 1) precipitating an acidic copper and bismuth-containing aqueous solution onto a particulate support using a precipitating agent; 2) drying the treated particulate support and calcining it at 300-800°C to form a catalyst composition; wherein the particulate support comprises alumina.

10. A method for producing 1,4-butynediol from acetylene and formaldehyde, using the catalyst composition of any one of claims 1 to 8.

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