Mesoporous NiO-Al with alkaline carrier material2O3Molybdenum-based catalyst for preparing low-carbon alcohol from synthesis gas as carrier and preparation method thereof
阅读说明：本技术 以碱性载体材料介孔NiO-Al2O3为载体的合成气制低碳醇钼基催化剂及其制备方法 (Mesoporous NiO-Al with alkaline carrier material2O3Molybdenum-based catalyst for preparing low-carbon alcohol from synthesis gas as carrier and preparation method thereof ) 是由 胡瑞珏 屈皓 苏海全 于 2020-12-30 设计创作，主要内容包括：本发明公开了一种以碱性载体材料介孔NiO-Al-2O-3为载体的合成气制低碳醇钼基催化剂及其制备方法,属于催化剂技术领域。所述催化剂由以下步骤制得：合成前体NiAl-LDH；将所得NiAl-LDH进行升温煅烧,得煅烧材料NiO-Al-2O-3；制备MoS-2-NiO-Al-2O-3；将(NH-4)-2MoS-4溶于浓氨水中,再加入NiO-Al-2O-3不断搅拌,晾干后研磨,再进行烧制,冷却后得MoS-2-NiO-Al-2O-3；将MoS-2-NiO-Al-2O-3与K-2CO-3研磨混合压片,过筛,得K-Mo-S/NiO-Al-2O-3。该催化剂具有优异的合成气制低碳醇活性、高的醇选择性和运行稳定性,成本低且制备方便。(The invention discloses a mesoporous NiO-Al with an alkaline carrier material 2 O 3 A molybdenum-based catalyst for preparing low-carbon alcohol from synthesis gas as a carrier and a preparation method thereof, belonging to the technical field of catalysts. The catalyst is prepared by the following steps: synthesizing a precursor NiAl-LDH; heating and calcining the obtained NiAl-LDH to obtain a calcined material NiO-Al 2 O 3 (ii) a Preparation of MoS 2 ‑NiO‑Al 2 O 3 (ii) a Will be (NH) 4 ) 2 MoS 4 Dissolving in concentrated ammonia water, adding NiO-Al 2 O 3 Continuously stirring, air-drying, grinding, firing, and cooling to obtain MoS 2 ‑NiO‑Al 2 O 3 (ii) a Mixing MoS 2 ‑NiO‑Al 2 O 3 And K 2 CO 3 Grinding, mixing, tabletting and sieving to obtain K-Mo-S/NiO-Al 2 O 3 . The catalyst has excellent activity of preparing low-carbon alcohol from synthesis gas, high alcohol selectivity and operation stability, low cost and convenient preparation.)
1. Mesoporous NiO-Al with alkaline carrier material2O3The preparation method of the molybdenum-based catalyst for preparing the low-carbon alcohol from the synthesis gas as the carrier is characterized by comprising the following steps of:
step one, synthesizing a precursor NiAl-LDH: adding Ni (NO) in sequence according to the proportion3)2·6H2O，Al(NO3)3·9H2Stirring O and a template agent to react for a certain time, adjusting the pH, and washing and drying the precipitate to obtain NiAl-LDH;
step two, calcining: heating and calcining the NiAl-LDH obtained in the step one to obtain a calcined material NiO-Al2O3；
Step three, preparing MoS2-NiO-Al2O3: will be (NH)4)2MoS4Dissolving in concentrated ammonia water, adding NiO-Al2O3Continuously stirring, airing at room temperature, grinding, firing the product, and naturally cooling to obtain MoS2-NiO-Al2O3；
Step four, preparing the low-carbon alcohol molybdenum-based catalyst by using the synthesis gas: the product MoS obtained in the third step2-NiO-Al2O3And K2CO3Grinding, mixing, tabletting and sieving to obtain the catalyst K-Mo-S/NiO-Al for preparing low-carbon alcohol from synthesis gas2O3。
2. The mesoporous NiO-Al with basic support material as claimed in claim 12O3Synthesis for the supportThe preparation method of the gas-to-low carbon alcohol molybdenum-based catalyst is characterized in that the template agent and Ni (NO) are adopted3)2·6H2O and Al (NO)3)3·9H2The molar ratio of O is 0.014-0.033: 3: 1.
3. the mesoporous NiO-Al with basic support material as claimed in claim 12O3The preparation method of the molybdenum-based catalyst for preparing the low-carbon alcohol from the synthesis gas serving as the carrier is characterized in that the template agent in the step one is P123 or F127.
4. The mesoporous NiO-Al with basic support material as claimed in claim 32O3The preparation method of the low-carbon alcohol molybdenum-based catalyst prepared from the synthesis gas serving as the carrier is characterized in that the calcined material NiO-Al in the step two2O3Expressed as niao-F127/P123-X% -Y, where X ═ 3, 5 or 7, and Y ═ 320 ℃, 500 ℃ or 750 ℃.
5. The mesoporous NiO-Al with basic support material as claimed in claim 12O3The preparation method of the low-carbon alcohol molybdenum-based catalyst prepared from the synthesis gas serving as the carrier is characterized in that the stirring reaction time in the step one is 1-4 hours.
6. The mesoporous NiO-Al with basic support material as claimed in claim 12O3The preparation method of the low-carbon alcohol molybdenum-based catalyst prepared from the synthesis gas serving as the carrier is characterized in that the pH is adjusted to 9.5-11 in the step one, and the pH is adjusted by using an alkaline solution; and step one, drying the precipitate at 60 ℃ for 12-48 h under vacuum.
7. The mesoporous NiO-Al with basic support material as claimed in claim 62O3The preparation method of the low-carbon alcohol molybdenum-based catalyst by using the synthesis gas as the carrier is characterized in that in the step one, 1-2 mol/L sodium hydroxide solution is used for adjusting the pH value.
8. The method of claim 1Mesoporous NiO-Al of alkaline carrier material2O3The preparation method of the molybdenum-based catalyst for preparing the low-carbon alcohol from the synthesis gas as the carrier is characterized in that (NH) added in the third step4)2MoS4And NiO-Al2O3The molar ratio of (a) to (b) is 0.1 to 0.5: 1-3, firing the product specifically comprises the following steps: the temperature rise program is 5 ℃/min, and the temperature is kept for 4h at 550 ℃.
9. The mesoporous NiO-Al with basic support material as claimed in claim 12O3The preparation method of the low-carbon alcohol molybdenum-based catalyst prepared from the synthesis gas serving as the carrier is characterized by comprising the step four of MoS2-NiO-Al2O3And K2CO3The molar ratio of (a) to (b) is 3-10: 0.1 to 0.7.
10. Mesoporous NiO-Al with basic support material according to any of claims 1 to 92O3The synthesis gas prepared by the preparation method of the low-carbon alcohol molybdenum-based catalyst by using the synthesis gas as a carrier is used for preparing the low-carbon alcohol molybdenum-based catalyst.
Technical Field
The invention belongs to the field of synthesis gas (CO and H)2) The technical field of catalysts for preparing mixed low-carbon alcohol, in particular to a mesoporous NiO-Al with an alkaline carrier material2O3A molybdenum-based catalyst for preparing low-carbon alcohol from synthesis gas as a carrier and a preparation method thereof.
Background
The lower mixed alcohol is called low-carbon alcohol for short, and is represented by C1～C5Alcohol, and a liquid mixture. The low-carbon alcohol has high octane number, good miscibility with gasoline, excellent combustion, chemical processing and other properties, and can replace seriously polluted methyl tert-butyl ether (MTBE) to become a preferred clean gasoline additive. The low-carbon alcohol can also be used as a new-generation low-pollution clean fuel of the engine to directly replace petroleum. Meanwhile, ethanol and the like C2+Alcohols (mixture of ethanol, propanol, butanol, pentanol, etc.) are bulk chemical raw materials and have wide application. The synthesis gas is prepared from coal, natural gas, biomass and the like, and is catalytically converted into C such as ethanol2+The alcohol can save grains, reduce environmental pollution and relieve the overlarge consumption pressure of the grain industry in China. If the process of preparing ethanol from synthesis gas is combined with the ethanol dehydration process, ethylene can be directly generated, the existing petrochemical route is replaced to a certain extent, and the problem that the world petroleum resources are increasingly in short supply is expected to be solved.
At present, a great deal of reports are available on the synthesis of lower alcohols by hydrogenation of carbon monoxide. Of these, four types of catalysts are representative. (1) Modification ofMethanol synthesis catalyst (Cu-Zn/Al, Zn-Cr): the catalyst is obtained by modifying a methanol synthesis catalyst by adding a proper amount of alkali metal or alkaline earth metal compound, and more typical patents include C.E. Hofsta et al EP-0034338-A2 and U.S. Pat. No. 4513100 (funded by Snam corporation, invented by Fattore et al). Although the catalyst has high activity and high isobutanol content in the product, the reaction conditions are harsh (the pressure is 14-20MPa, the temperature is 350-450 ℃), and the reaction temperature is C2+The alcohol selectivity is low (generally less than 35 percent), and the water content in the product is high (generally 30 to 50 percent); (2) Cu-Co catalyst: the french institute for petroleum (IFP) first developed Cu-Co coprecipitation lower alcohol catalysts (US Patent 4122110,4291126 and GB Patent 218061,2158730). The products synthesized by the catalyst are mainly C1-C6Straight chain normal alcohol, the by-product is mainly C1～C6Aliphatic hydrocarbons, the reaction conditions are mild, but the stability is poor. (3) Rh-based catalysts (e.g. US Patent 4014913 and 4096164): after one or two transition metal or metal oxide assistants are added into the supported Rh catalyst, the supported Rh catalyst has higher activity and selectivity on low-carbon alcohol, especially on C2+The selectivity of the alcohol is higher, and the product is mainly ethanol. However, Rh compound is expensive and the catalyst is liable to be CO2And (4) poisoning. (4) MoS2Base catalyst: molybdenum sulfide catalysts developed by DOW corporation in the united states (US Patent 4882360, EP0119609A) are MoS catalysts doped with a base2The composition has unique sulfur resistance, is not easy to form carbon, and can be used in the field of high sulfur content (20-100 mg/m)3) And lower H2The catalyst is used under the condition of raw material gas with a/CO ratio of 0.7-1. Thus avoiding the problems of harsh conditions and expensive cost brought by the deep desulfurization process of the raw material gas. At the same time, the product has a low water content, C2+The alcohol selectivity is high and reaches 30-70%, wherein ethanol and n-propanol are mainly used. In recent years, molybdenum sulfide catalyst systems have been studied more extensively in Shanxi coal chemical industry of Chinese academy of sciences (see CN1631527A, CN1663683A, CN1431049A, etc.). The industrialization of the low carbon alcohol synthesis process is attracting increasing attention in the fuel chemical industry, and how to improve the activity and selectivity of the catalyst to improve the efficiency of the production process becomes a technical bottleneck restricting the practicability and industrialization of the low carbon alcohol synthesis process.
Although the MoS is modified with an alkali metal compound adjuvant2The base catalyst has good performance of synthesizing low-carbon alcohol, but is far from the requirement of large-scale industrial production, and the main problems are low yield of alcohol and relatively high content of methanol in the product. The great improvement of the overall activity and the selectivity of the alcohol is the research focus of this type of catalyst. Active component MoS in molybdenum disulfide catalyst system2The low specific surface area, and the limitation of particle size and morphology are also one of the factors that restrict the activity and alcohol selectivity. The silicon oxide mesoporous material is considered as an ideal novel catalyst carrier due to higher specific surface area, larger pore volume, thicker pore wall and regular pore channel and improved mechanical hydrothermal stability (Zhao D Y, et., Science,1998,279: 548-. A molybdenum disulfide catalyst taking SBA-15 as a carrier is reported to be used for hydrodesulfurization reaction (Huang Z D, et Al, Catal.Lett.,2008,124:24-43), active components Co and Mo are loaded on an SBA-15 mesoporous material through an impregnation method, and the hydrodesulfurization reaction of the catalyst CoMo/SBA-15 prepared through roasting and vulcanization is compared with CoMo/gamma-Al for the hydrodesulfurization reaction of diphenylthiophene2O3Has higher reactivity and selectivity. The performance of the catalyst for the reaction of preparing the low carbon alcohol from the synthesis gas is a result of the synergistic effect of various complex factors, and the chemical composition of the carrier, the pore structure (pore size and pore size distribution) of the carrier, the acidity and alkalinity of the carrier, the particle size, the dispersion and the morphology of the active components, the interaction among the carriers of the active components and the like all influence the reaction activity, the product selectivity and the operation stability of the catalyst. The carrier is acidic, which is beneficial to the selectivity of hydrocarbons in the catalytic product of the synthesis gas; and the alkaline carrier is favorable for the selectivity of the alcohol in the product.
Disclosure of Invention
The invention aims to solve the defects of the prior art and provide a mesoporous NiO-Al with an alkaline carrier material2O3The catalyst can effectively improve the conversion per pass, the selectivity of low-carbon alcohol and the space-time yield, and has excellent activity for preparing low-carbon alcohol from synthesis gas and high alcohol contentSelectivity and operation stability, low cost, convenient preparation and practical application value.
The invention adopts the following technical scheme:
mesoporous NiO-Al with alkaline carrier material2O3The preparation method of the molybdenum-based catalyst for preparing the low-carbon alcohol from the synthesis gas as the carrier comprises the following steps:
step one, synthesizing a precursor NiAl-LDH: adding Ni (NO) in sequence according to the proportion3)2·6H2O，Al(NO3)3·9H2Stirring O and a template agent to react for a certain time, adjusting the pH, and washing and drying the precipitate to obtain NiAl-LDH;
step two, calcining: heating and calcining the NiAl-LDH obtained in the step one to obtain a calcined material NiO-Al2O3；
Step three, preparing MoS2-NiO-Al2O3: will be (NH)4)2MoS4Dissolving in concentrated ammonia water, adding NiO-Al2O3Continuously stirring, airing at room temperature, grinding, firing the product, and naturally cooling to obtain MoS2-NiO-Al2O3；
Step four, preparing the low-carbon alcohol molybdenum-based catalyst by using the synthesis gas: the product MoS obtained in the third step2-NiO-Al2O3And K2CO3Grinding, mixing, tabletting and sieving to obtain the catalyst K-Mo-S/NiO-Al for preparing low-carbon alcohol from synthesis gas2O3。
Further, the template, Ni (NO)3)2·6H2O and Al (NO)3)3·9H2The molar ratio of O is 0.014-0.033: 3: 1.
further, in the first step, the template agent is P123 (polyethylene glycol polypropylene glycol triblock polymer) or F127 (polyethoxy polypropoxy triblock polymer).
Further, the calcined material NiO-Al in the second step2O3Expressed as niao-F127/P123-X% -Y, where X ═ 3, 5 or 7, and Y ═ 320 ℃, 500 ℃ or 750 ℃.
Further, the stirring reaction time in the step one is 1-4 h.
Further, adjusting the pH value to 9.5-11 in the step one, and adjusting by using an alkaline solution; and step one, drying the precipitate at 60 ℃ for 12-48 h under vacuum.
Furthermore, in the first step, 1-2 mol/L sodium hydroxide solution is used to adjust the pH.
Further, addition of (NH) in step three4)2MoS4And NiO-Al2O3The molar ratio of (a) to (b) is 0.1 to 0.5: 1-3, firing the product specifically comprises the following steps: the temperature rise program is 5 ℃/min, and the temperature is kept for 4h at 550 ℃.
Further, MoS in step four2-NiO-Al2O3And K2CO3The molar ratio of (a) to (b) is 3-10: 0.1 to 0.7.
The invention also provides the alkaline carrier material mesoporous NiO-Al2O3The synthesis gas prepared by the preparation method of the low-carbon alcohol molybdenum-based catalyst by using the synthesis gas as a carrier is used for preparing the low-carbon alcohol molybdenum-based catalyst.
Compared with the prior art, the invention has the beneficial effects that:
firstly, the method comprises the following steps: the invention takes NiAl double-metal layered hydroxide (NiAl-LDH) as an alkaline carrier material, namely mesoporous NiO-Al2O3Calcining the precursor by taking F127 or P123 as a template agent to generate a mesoporous carrier; (NH)4)2MoS4Is used as an active component raw material, and a mesoporous structure catalyst MoS with uniform particles and narrow pore size distribution is prepared by two steps of isochoric impregnation and thermal decomposition2-NiAlOxThe catalyst can realize the modulation of the particle size, the pore diameter and the pore volume of the carrier by changing the preparation conditions (temperature, concentration, pressure, reaction ratio and the like).
Secondly, the method comprises the following steps: the catalyst of the invention has the characteristics of sulfur resistance, no carbon deposition and good operation stability.
Thirdly, the method comprises the following steps: when the catalyst prepared by the invention is used, the CO conversion rate can reach 38 percent, and the selectivity of the total alcohol can reach 88.2 percent; the space-time yield of total alcohol was > 107mg/g cat/h.
Drawings
FIG. 1 is an XRD test pattern of a precursor NiAl-LDH of the present invention;
FIG. 2 shows the NiO-Al carrier of the present invention2O3(MMO) XRD test pattern;
FIG. 3 is (NH)4)2MoS4XRD test pattern of (1);
FIG. 4 shows the catalyst MoS2-NiO-Al2O3XRD test pattern of (1).
Detailed Description
The present invention is further illustrated by the following examples and accompanying drawings, it is to be understood that these examples are given solely for the purpose of illustration and not as a definition of the limits of the invention, and that various equivalent modifications of the invention which fall within the limits of the appended claims will become apparent to those skilled in the art upon reading the present disclosure.
Example 1
(1) Mesoporous NiO-Al of alkaline carrier material2O3
Soft template method for synthesizing ordered mesoporous metal oxide NiO-Al2Precursor of O NiAl-LDH (NiAl double metal layered hydroxide): adding Ni (NO) in proportion3)2·6H2O，Al(NO3)3·9H2O and a template P123/F127 (the amounts of the added materials are shown in Table 1), and the mixture is stirred vigorously at room temperature (the stirring time is 1 hour, and the rotating speed is 250 rpm). The final reaction mixture was adjusted to pH 10.0 with sodium hydroxide solution (concentration 1mol/L), and the resulting precipitate was filtered, washed and dried (several times with distilled water until the pH of the filtrate was 7, and then the washed precipitate was dried under vacuum at 60 ℃ for 12 hours) to give NiAl-LDH;
then the NiAl-LDH is calcined in a muffle furnace by temperature programming (the temperature of the calcination in the muffle furnace is increased by 5 ℃ per minute, the calcination time is 5 hours), and the obtained calcined material NiO-Al is added2O3Expressed as NiAlO-F127/P123-X% -Y, wherein X represents the percentage content of the template agent; y represents the calcination temperature in degrees celsius).
TABLE 1 mesoporous metal oxide NiO-Al2Preparation material ratio of precursor NiALDH of O
As can be seen from FIG. 1, F127 was added in different amounts, but the peak positions of the precursors remained substantially the same, with diffraction planes at 11.37 °, 23.08 °, 34.81 °, 39.19 °, 46.79 °, 60.68 ° being NiAl (OH) respectively4(003), (006), (009), (015), (018), (110).
As can be seen from FIG. 2, the amount of F127 added was 3%, and the peak was more pronounced at a calcination temperature of 750 ℃ and the crystallization was better. The amount of F127 added was 5%, and the crystallinity was slightly poor at a calcination temperature of 320 ℃. By comparison with a standard card, the carrier NiAlO contained both monoclinic NiO and cubic Al.
(2) Catalyst K-Mo-S/NiO-Al2O3
Firstly, synthesizing a precursor NiAl-LDH by adopting a coprecipitation method: 0.015mol of nickel nitrate hexahydrate and 0.005mol of aluminum nitrate nonahydrate are added into a beaker, then different amounts of F127 or P123 are added and dissolved in 30mL of deionized water under stirring, then the pH value of the system is adjusted to be approximately equal to 10.0 by 2mol/LNaOH (aq), and the stirring speed is increased gradually when NaOH (aq) is added, so that the local pH value is prevented from being too high to influence the measurement. The suspension was heated in an ultrasonic water bath at 65 ℃ for 1 hour. Then centrifugal separation is carried out, and the light green solid precipitate is washed for more than 3 times by deionized water until the pH value of clear liquid is 7. The product was placed in a vacuum oven and dried under vacuum at 60 ℃ for 12 h. The variables in the experiment were the amount of F127 or P123 added, expressed as X%. The product LDH was weighed and recorded (see table 1).
Grinding LDH into powder, putting the powder into a muffle furnace for calcination, heating the powder at a temperature of 5 ℃/min, calcining at 320 ℃ to obtain a black product, calcining at 750 ℃ to obtain a green product, and preparing a NiO-Al product2O3Specifically expressed as NiAlO-F127/P123-X% -Y (X: the percentage content of the template agent F127 or P123 is 3, 5 and 7%; Y: the calcination temperature is 320,500 and 750 deg.c). The product was weighed and recorded.
1.221g of (NH) are accurately weighed out on an analytical balance4)2MoS4Dissolved in 9ml of concentrated ammonia water. Then accurately weighing 3.00g of NiO-Al by using an analytical balance2O3Adding into a beaker for dipping and stirring continuously. Air-drying at room temperature for 1-2 days, and grinding the product with a mortar. Placing the sample in a container with N2Firing in a tubular furnace of protective gas, heating at 5 ℃/min, keeping at 550 ℃ for 4h, and naturally cooling to obtain MoS2-NiO-Al2O3Black powder. Mixing the brown black powder 2.00g with 0.333g K2CO3Grinding, mixing, tabletting, and sieving with 40-60 mesh sieve. Obtaining the catalyst K-Mo-S/NiO-Al for preparing the low-carbon alcohol by the synthesis gas2O3. Wherein the mass fraction of the active component Mo is 10.2%, the mass fraction of the additive K is 4.0%, and the carrier NiO-Al2O3The mass fraction of (b) is 68.5%.
From the catalyst MoS of FIG. 42-NiAlOxThe XRD test analysis result shows that Ni3S2The characteristic peak position and the corresponding crystal plane are: 21.77 ° (101), 30.82 ° (012), 31.13 ° (110), 37.78 ° (003), 38.31 ° (021), 44.37 ° (202), 49.7 ° (113), 50.16 ° (211), 54.6 ° (104), 55.2 ° (122), 55.4 ° (300); the characteristic peak position and the corresponding crystal plane of Cubic NiO are 37.3 degrees (111) and 62.9 degrees (220); NiAl2O4：Cubic 37.0°(311)，45.0°(400)，65.5°(440)；Monoclinic MoO2The characteristic peak position and the corresponding crystal plane are: 26.0 ° (11-1), 26.04 ° (110), 37.0 ° (111), Hexagonal NiS characteristic peak positions and corresponding crystal planes are: 29.9 ° (100), 34.3 ° (101), 45.2 ° (102), 53.2 ° (110), Hexagonal MoS2The characteristic peak position and the corresponding crystal plane are: 14.4 ° (002), 39.6 ° (013), 49.9 ° (015), 32.8 ° (010), Ni among them3S2Mainly occurs in the final product obtained when the calcination temperature of the carrier is 320 ℃, MoS2Mainly in the final product obtained at a calcination temperature of the support of 750 c. As a result of the analysis, MoS2The reason for the low content may be due to O and MoS in the carrier2S in the molybdenum is replaced to MoO2The forms of (a) exist in large numbers.
Evaluation of catalytic activity of catalyst for preparing low-carbon alcohol from synthesis gas in pressurized fixed bed continuous flow reactorOn a GC system. The catalyst loading was 2.0 g; the raw material gas is synthesis gas, and H is controlled2The ratio of the catalyst to the catalyst is 1:1, Ar is used as an internal standard, and the space velocity is 3000h-1The reaction was carried out under the reaction conditions of 11MP and 320 ℃. After the reaction is stabilized and balanced, the mixed alcohol in the tail gas is analyzed on line by a gas chromatograph of GC-2014C of Shimadzu company of a Stabilmax capillary column and provided with a hydrogen flame detector (FID); CO, Ar, CH in tail gas4And CO2On-line analysis was performed by a gas chromatograph GC-2014C of Shimadzu corporation equipped with a TDX-01 stationary phase column, Thermal Conductivity Detector (TCD); the mixed hydrocarbons in the tail gas were analyzed on-line by a Shimadzu GC-2014C gas chromatograph equipped with a Propack-Q stationary phase chromatographic column equipped with a FID detector.
The results of evaluating the catalytic activity of the catalyst for producing lower alcohols from synthesis gas are shown in Table 2.
Wherein the catalyst with the most excellent performance is Mo-S-K2CO3/NiAlO-F127-5％-320℃。
The preparation method of the catalyst comprises the following steps: 0.015mol of 4.36 g of nickel nitrate hexahydrate and 0.005mol of 1.88 g of aluminum nitrate nonahydrate are added into a beaker, 5 percent of F1270.45 g is added and dissolved in 30mL of deionized water under stirring, then the pH value of the system is adjusted to be approximately equal to 10.0 by 2mol/L NaOH (aq), the stirring is vigorously carried out when NaOH (aq) is added, and the stirring speed is gradually increased to prevent the local pH value from being too high to influence the measurement. The suspension was heated in an ultrasonic water bath at 65 ℃ for 1 hour. Then centrifugal separation is carried out, and the light green solid precipitate is washed for more than 3 times by deionized water until the pH value of clear liquid is 7.
And (3) putting the product in a vacuum drying oven, drying for 12h at 60 ℃ under a vacuum condition to obtain NiAl-LDH, grinding the NiAl-LDH into powder, putting the powder into a muffle furnace for calcination, and heating the powder at a temperature of 5 ℃/min, wherein the product is black NiAlO-F127-5-320 ℃ after calcination at 320 ℃.
Mixing the brown black powder 2.00g with 0.333g K2CO3Grinding, mixing, tabletting, and sieving with 40-60 mesh sieve to obtain the catalyst Mo-S-K for preparing low carbon alcohol from synthesis gas2CO3NiAlO-F127-5% -320 ℃), the total alcohol selectivity of the catalyst is up to 72.7% under the reaction conditions of 11MP and 320 ℃, and C2+The selectivity of alcohol is as high as 77.8%.
TABLE 2 catalyst K-Mo-S/NiO-Al2O3Evaluation of (2)
The results of the evaluation of the catalytic activity of the catalyst in the preparation of lower alcohols from synthesis gas are shown in Table 2. As can be seen from table 2: K-Mo-S/NiO-Al2The O series catalyst can effectively catalyze CO hydrogenation to prepare low-carbon mixed alcohol. Under the reaction conditions of 11MP and 320 ℃, the selectivity of alcohols in the product is higher than 64.6 percent, and C is2+The proportion of the alcohol in the total alcohol is higher than 50 percent; catalyst C obtained when template is used F127 when prepared2+The alcohol selectivity was overall better than that of the catalyst obtained with P123, the former C2+The proportion of the alcohol in the total alcohol is higher than 66%; wherein the catalyst with the most excellent performance is Mo-S-K2CO3NiAlO-F127-5% -320 ℃, the total alcohol selectivity is up to 72.7%, C2+The proportion of alcohol in the total alcohol is up to 77.8 percent, C2+The selectivity of the alcohol in the total liquid product is as high as 56.6 percent.
Counter catalyst Mo-S-K2CO3The influence of the reaction temperature of NiAlOx-P123-3% -750 ℃ at 11MP and 290-320 ℃ on the catalytic performance is evaluated, and experiments show that: the effect of increasing temperature on the CO conversion of the catalyst was insignificant, with CO conversion at 290 ℃ of about 12% and at 305 and 320 ℃ of about 13%; the selectivity of total alcohol decreased significantly with increasing temperature (76.8% at 290 ℃, 71.1% at 305 ℃ and 64.6% at 320 ℃), while C was2+The distribution ratio of alcohol was significantly increased (59.0% at 290 ℃, 66.9% at 305 ℃ and 74.4% at 320 ℃), and C was found to increase with increasing temperature2+The selectivity of the total liquid alcohol product was also slightly increased (45.3% at 290 ℃, 47.5% at 305 ℃ and 48.1% at 320 ℃), as was the space-time yieldAnd also increases with reaction temperature.
The embodiments of the present invention have been described in detail with reference to the above examples, but the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge of those skilled in the art. The above description is only for the purpose of illustrating preferred embodiments of the present invention and is not intended to limit the scope of the present invention, which is defined by the appended claims.