A method for continuously synthesizing high-carbon ketone alcohols by catalyzing ethanol in one step

Abstract

The invention discloses a method for catalyzing ethanol to continuously synthesize high-carbon ketone alcohols in one step, and relates to the technical field of synthesis of high-carbon ketone and alcohol compounds. x The high-carbon ketones and high-carbon alcohols were synthesized continuously through a one-step fixed-bed heterogeneous catalytic process under the catalysis of the catalyst. x The catalyst can realize the effective coupling of a series of elementary steps such as ethanol dehydrogenation, ketonization reaction, nucleophilic attack, carbon-carbon bond breaking and hydrogenation, and obtain C7+ high-carbon ketones and alcohol-based oil phase products with high selectivity under the preferred reaction conditions.

Description

Technical Field

[0001] The invention belongs to the technical field of catalytic synthesis of high-carbon ketone and alcohol compounds, and particularly relates to a method for catalyzing ethanol to continuously synthesize high-carbon ketone alcohols in one step. Background Art

[0002] As energy and fuel security and environmental issues become increasingly prominent, the development and production of renewable fuels and chemicals have received widespread attention. High-carbon ketones and high-carbon alcohols can be used as precursors of sustainable hydrocarbon fuels, lubricants and fine chemicals, and have important applications. The development of alternative synthesis methods for high-carbon ketone alcohols is of great significance. However, high-carbon ketone alcohols are difficult to synthesize in a simple one-step manner and have a low carbon number range. Summary of the invention

[0003] In view of the above technical problems, the present invention proposes a method for catalyzing ethanol to continuously synthesize high-carbon ketone alcohols in one step. The method solves the defects and shortcomings of expensive precious metal catalysts, difficult product carbon chain growth (low selectivity of C7+ products), and low ethanol conversion efficiency. With ethanol as the initial raw material, high-carbon ketones and high-carbon alcohols are continuously synthesized through a single-step fixed bed heterogeneous catalytic process under the catalysis of CuZnZrOx catalyst. With the help of the multifunctional CuZnZrOx catalyst, the effective coupling of a series of elementary steps such as ethanol dehydrogenation, ketonization reaction, nucleophilic attack, carbon-carbon bond breaking and hydrogenation is achieved, and an oil phase product mainly composed of C7+ high-carbon ketones and alcohols is obtained with high selectivity under preferred reaction conditions.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A method for catalyzing ethanol to continuously synthesize high-carbon ketone alcohols in one step, wherein anhydrous ethanol and an inert gas are introduced into a CuZnZrO x A one-step continuous reaction is carried out in a fixed bed reactor of the catalyst to obtain a product, and the product is continuously condensed to obtain C7+ high-carbon ketone alcohol.

[0006] Furthermore, the method specifically comprises the following steps:

[0007] The catalyst is filled into a fixed bed reactor and a high temperature reduction reaction is carried out in a hydrogen atmosphere;

[0008] The atmosphere in the fixed bed reactor is switched to an inert atmosphere, and anhydrous ethanol is added to react to obtain C7+ high-carbon ketone alcohols.

[0009] Furthermore, the preparation method of the catalyst comprises the following steps: adding copper salt, zinc salt and zirconium salt into water to dissolve, then mixing with NaOH solution, stirring, aging, washing, drying and calcining to obtain CuZnZrO x catalyst.

[0010] Furthermore, the molar ratio of copper, zinc and zirconium is (0.1-0.5):0.43:1;

[0011] The copper salt is one or more of copper nitrate, copper chloride and copper acetate;

[0012] The zinc salt is one or more of zinc nitrate, zinc chloride and zinc acetate;

[0013] The zirconium salt is one or more of zirconium nitrate, zirconium citrate and zirconium hydroxide;

[0014] The calcination parameters are: heating rate 5°C / min, temperature 550°C, and time 3h.

[0015] Furthermore, the parameters of the high temperature reduction reaction under hydrogen atmosphere are: pressure 0.1 MPa, gas hourly space velocity 600-3000h -1 , heating rate 5℃ / min, temperature 300-400℃, reaction time 2h.

[0016] Furthermore, the reaction parameters under the inert atmosphere are: pressure 1.0-4.0 MPa, temperature 300-360°C, liquid space velocity 0.3-1.2 h -1 , gas hourly space velocity 600-3000h -1 , reaction time 12h.

[0017] Furthermore, the inert atmosphere is a nitrogen atmosphere or an argon atmosphere.

[0018] The present invention also provides a high-carbon ketol prepared by the above preparation method.

[0019] The reaction mechanism of the invention comprises the following steps: ethanol dehydrogenation as the starting elementary step, acetaldehyde condensation and chain scission to obtain acetone intermediates and aldehyde intermediates, and then aldehyde-ketone coupling, Guerbet coupling and other elementary reaction steps to synthesize high-carbon ketones and high-carbon alcohols. The synthesis method realizes the synchronous carbon chain growth of double CC coupling active sites by utilizing the double-sided electronegative carbon nucleophilic centers of the intermediate acetone, thereby improving the selectivity of C7+ high-carbon ketone alcohols.

[0020] Compared with the prior art, the present invention has the following advantages and technical effects:

[0021] The invention comprehensively considers the active centers and reaction conditions required for the orderly coupling of a series of elementary steps such as ethanol dehydrogenation, ketonization reaction, nucleophilic attack, carbon-carbon bond breaking and hydrogenation, and proposes a synthesis method which takes ethanol dehydrogenation as the starting elementary step, obtains acetone intermediates and aldehyde intermediates through acetaldehyde condensation and chain breaking, and then synthesizes high-carbon ketones and high-carbon alcohols through elementary reaction steps such as aldehyde-ketone coupling and Guerbet coupling. The synthesis method realizes the synchronous carbon chain growth of double CC coupling active sites by utilizing the double-sided electronegative carbon nucleophilic centers of the intermediate acetone, thereby improving the selectivity of C7+ high-carbon ketone alcohols.

[0022] The present invention constructs CuZnZrO by co-precipitation strategy x Composite catalyst promotes the reaction of Cu and ZnZrO x The oxide carrier forms a strong metal-carrier interaction and simultaneously forms acid-base catalytic active sites, which promotes the one-step catalytic conversion of ethanol to C7+ high-carbon ketone alcohols through CC coupling and aldehyde-ketone condensation. At the same time, the appropriate ratio of copper, zinc and zirconium metals can effectively inhibit the production of bond breaking by-products and promote carbon chain growth.

[0023] The synthesis method provided by the present invention has the advantages of simple preparation, low cost, high loading, low particle size, excellent catalytic efficiency, high reaction activity, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0025] Figure 1 The CuZnZrO prepared in Example 1 of the present invention x XRD pattern of catalyst. DETAILED DESCRIPTION

[0026] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0027] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0028] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0029] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0030] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0031] The C7+ high carbon ketone alcohols described in the present invention refer to: the sum of the total amount of high carbon ketones and high carbon alcohols with a carbon number of 7 or more (including 7), and the high carbon ketone alcohols here refer to high carbon ketones and high carbon alcohols.

[0032] The present invention provides a method for catalyzing ethanol to continuously synthesize high-carbon ketone alcohols in one step, wherein anhydrous ethanol and an inert gas are introduced into a fixed bed reactor loaded with a catalyst for a one-step continuous reaction to obtain a product, and the product is continuously condensed to obtain an oil-water separation product, wherein the oil phase product is mainly a C7+ high-carbon ketone alcohol product. Bioethanol technology already has a large-scale industrial foundation, so the present invention uses ethanol as a raw material to synthesize high-carbon ketones and alcohols, which has the dual advantages of green and low-carbon and large-scale supply, and is a potential high-carbon ketone and alcohol alternative synthesis route.

[0033] A method for catalyzing the one-step continuous synthesis of high-carbon ketone alcohols from ethanol by using multifunctional CuZnZrO x The catalyst continuously synthesizes high-carbon ketones and high-carbon alcohols in a single-step fixed-bed heterogeneous catalytic process. The method for catalytically synthesizing high-carbon ketone alcohols is carried out in a fixed-bed reactor. The synthesis method comprises the following steps:

[0034] (1)CuZnZrO x Preparation of catalyst: copper salt, zinc salt and zirconium salt are dissolved in water, then mixed with NaOH solution, stirred, aged, washed, dried and calcined to obtain CuZnZrO x catalyst;

[0035] (2) CuZnZrO xThe catalyst is loaded into a fixed bed reactor and subjected to controlled high temperature reduction in a hydrogen gas atmosphere;

[0036] (3) The gas atmosphere of the fixed bed reactor is switched to an inert atmosphere, and anhydrous ethanol is added to the fixed bed reactor by a horizontal flow pump, and the reaction pressure, temperature, gas space velocity, and ethanol liquid velocity are adjusted to carry out the reaction.

[0037] In some preferred embodiments, in step (1), the molar ratio of copper, zinc and zirconium is (0.1-0.5):0.43:1, preferably 0.3:0.43:1;

[0038] The copper salt is one or more of copper nitrate, copper chloride and copper acetate, preferably copper nitrate;

[0039] The zinc salt is one or more of zinc nitrate, zinc chloride and zinc acetate, preferably zinc nitrate;

[0040] The zirconium salt is one or more of zirconium nitrate, zirconium citrate and zirconium hydroxide, preferably zirconium nitrate;

[0041] The calcination parameters are: heating rate 5°C / min, temperature 550°C, and time 3h.

[0042] In some preferred embodiments, step (2) of the high temperature reduction reaction in hydrogen atmosphere has the following parameters: pressure 0.1 MPa, gas hourly space velocity 600-3000 h -1 (Preferably 2400h -1 ), heating rate 5°C / min, temperature 300-400°C (preferably 400°C), reaction time 2h.

[0043] In some preferred embodiments, step (3), the reaction parameters under the inert atmosphere are: pressure 1.0-4.0 MPa (preferably 2.5 MPa), temperature 300-360° C. (preferably 330° C.), liquid space velocity 0.3-1.2 h -1 (Preferably 0.6h -1 ), gas hourly space velocity is 600-3000h -1 (Preferably 2400h -1 ), reaction time 12h.

[0044] The "normal temperature" mentioned in the present invention refers to 20-30°C unless otherwise specified.

[0045] The raw materials used in the present invention are all purchased from the market.

[0046] The technical solution of the present invention is further illustrated by the following embodiments.

[0047] Example 1

[0048] A method for synthesizing high-carbon ketone alcohols by catalyzing ethanol in one step, the steps are as follows:

[0049] (1)CuZnZrO x Preparation of catalyst:

[0050] Copper nitrate, zirconium nitrate and zinc nitrate were dissolved in distilled water at a molar ratio of 0.3:0.43:1 among copper, zinc and zirconium to prepare a 0.1M (total concentration) metal salt solution; NaOH was dissolved in distilled water to prepare a 0.1M alkaline solution; the two solutions were uniformly mixed at a volume ratio of 1:1 and stirred at 600 rpm for 2 hours, then fully washed until the pH of the system reached neutrality (pH=7), and then transferred to an oven at 110°C and dried for 12 hours to obtain CuZnZrO x Catalyst precursors;

[0051] CuZnZrO x The catalyst precursor was placed in a muffle furnace, heated to 550°C at 5°C / min, and calcined for 3 h to obtain CuZnZrO x catalyst.

[0052] (2) Loading CuZnZrO in a fixed bed reactor x Catalyst, mixed with quartz sand to maintain a certain catalyst bed (mixed with quartz sand to maintain a certain volume on the bed side, the amount used is 3mL, the same below); in a hydrogen atmosphere, the temperature was raised from room temperature to 400℃ at a rate of 5℃ / min for 2400h -1 Hydrogen gas space velocity 0.1MPa reduction for 2h;

[0053] (3) N 2 Inert gas atmosphere replaces H 2 , the pressure was increased to 2.5Mpa, the reaction temperature was 330℃, and the reaction time was 0.6h -1 Anhydrous ethanol was added to the reactor at a liquid rate of 2400 h. -1 , react for 12h.

[0054] Figure 1 The CuZnZrO prepared in Example 1 of the present invention x XRD diagram of the catalyst. It can be seen from the figure that the catalyst has no characteristic peaks of oxides and Cu is evenly dispersed on the carrier.

[0055] Example 2-15

[0056] A method for synthesizing high-carbon ketone alcohols by catalyzing ethanol in one step, wherein the steps are the same as those in Example 1, and the differences are shown in Table 1. The parameter variables in Table 1 refer to the parameter changes in step (3).

[0057] Table 1 Reaction parameters of the synthesis method of Examples 1-15

[0058]

[0059]

[0060] Example 16

[0061] Same as Example 1, except that the nitrogen atmosphere in step (3) is replaced by argon atmosphere.

[0062] Embodiment 17

[0063] Same as Example 1, except that in step (1), the molar ratio of copper, zinc and zirconium is 0.1:0.43:1.

[0064] Embodiment 18

[0065] Same as Example 1, except that in step (1), the molar ratio of copper, zinc and zirconium is 0.5:0.43:1.

[0066] Comparative Example 1

[0067] The same as Example 1, except that in step (1), the zinc salt and the zirconium salt are replaced by silica sol, and the molar ratio of copper to silicon is 0.3:1.

[0068] Comparative Example 2

[0069] Same as Example 1, except that no zinc salt is added in step (1), and the molar ratio of copper to zirconium is 0.3:1.

[0070] The gases produced by the reactions of the above-mentioned embodiments and comparative examples were collected and detected and analyzed by FID-TCD gas analysis spectrum. At the same time, the liquid products of the above-mentioned embodiments and comparative examples were centrifuged and layered, and the upper organic phase and the lower aqueous phase were taken after standing, and detected and analyzed by gas chromatography; the results are shown in Table 2.

[0071] Table 2 Analysis of reaction results of various embodiments and comparative examples

[0072]

[0073]

[0074] It can be seen from Table 2 that the performance of Comparative Examples 1 and 2 is significantly worse, and C cannot be synthesized in Comparative Example 1. 7 + High carbon ketones and high carbon alcohols indicate that long-chain ketone alcohol products require an acidic or alkaline carrier for aldehyde-ketone condensation. 7 +The content of high-carbon ketones and high-carbon alcohols is obviously insufficient, indicating that the zirconium oxide carrier is needed to provide sufficient acidic sites and coupling active sites during the reaction.

[0075] The present invention adopts CuZnZrO x The catalyst can catalyze the conversion of ethanol into C7+ high-carbon ketone alcohols in one step, with the ethanol conversion rate up to 95.6% and the selectivity of liquid product C7+ high-carbon ketone alcohol up to 60%. x The selectivity of gaseous by-products such as light hydrocarbons is less than 20%, which takes into account the balance of high ethanol conversion rate, long high-carbon ketone alcohol carbon chain and high selectivity.

[0076] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for catalyzing ethanol to continuously synthesize high-carbon ketone alcohols in one step, characterized in that: Anhydrous ethanol and inert gas are passed into the CuZnZrO x A one-step continuous reaction is carried out in a fixed bed reactor containing a catalyst to obtain a product, and the product is continuously condensed to obtain C7+ high-carbon ketone alcohol; The CuZnZrO x The preparation method of the catalyst comprises the following steps: adding copper salt, zinc salt and zirconium salt into water to dissolve, then mixing with NaOH solution, stirring, aging, washing, drying and calcining to obtain CuZnZrO x catalyst; The molar ratio of copper, zinc and zirconium in the copper salt, zinc salt and zirconium salt is (0.1-0.5):0.43:1; The copper salt is one or more of copper nitrate, copper chloride and copper acetate; The zinc salt is one or more of zinc nitrate, zinc chloride and zinc acetate; The zirconium salt is one or more of zirconium nitrate, zirconium citrate and zirconium hydroxide; The calcination parameters are: heating rate 5°C / min, temperature 550°C, and time 3h.

2. The method for continuously synthesizing high-carbon ketone alcohols from ethanol in one step according to claim 1, characterized in that: During the reaction, the pressure is 1.0-4.0MPa and the temperature is 300-360°C.

3. The method for catalyzing ethanol to continuously synthesize high-carbon ketone alcohols in one step according to claim 1, characterized in that: The gas hourly space velocity during the reaction is 0.3-1.2h -1 .

4. The method for catalyzing ethanol to continuously synthesize high-carbon ketone alcohols in one step according to claim 1, characterized in that: The heating rate during the reaction was 5°C / min and the reaction time was 12h.

5. The method for catalyzing ethanol to continuously synthesize high-carbon ketone alcohols in one step according to claim 1, characterized in that: The method specifically comprises the following steps: CuZnZrO x The catalyst is filled into a fixed bed reactor and subjected to high temperature reduction reaction in a hydrogen atmosphere; The hydrogen atmosphere in the fixed bed reactor is switched to an inert atmosphere, and anhydrous ethanol is added to react to obtain C7+ high-carbon ketone alcohols.

6. The method for catalyzing ethanol to continuously synthesize high-carbon ketone alcohols in one step according to claim 1, characterized in that: The conditions of the high temperature reduction reaction are: pressure of 0.1 MPa, gas hourly space velocity of 600-3000 h -1 , heating rate is 5℃ / min, temperature is 300-400℃, and reaction time is 2h.

7. The method for catalyzing ethanol to continuously synthesize high-carbon ketone alcohols in one step according to claim 1, characterized in that: The inert atmosphere is a nitrogen atmosphere or an argon atmosphere.

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