阅读说明：本技术 一种多相催化加氢中即时消除金属催化剂一氧化碳中毒的方法与应用 (Method for immediately eliminating carbon monoxide poisoning of metal catalyst in heterogeneous catalytic hydrogenation and application ) 是由 林海强 陈建 许康 段新平 袁友珠 于 2021-09-01 设计创作，主要内容包括：本发明公开了一种多相催化加氢中即时消除金属催化剂一氧化碳中毒的方法,步骤如下：在气或液流动态环境下使用金属催化剂催化多相加氢反应时,通过往反应体系中引入少量氧化性气体即可消除或防止金属催化剂的一氧化碳中毒。本发明所提供的方法是通过往反应气氛中掺入微量的氧气或氧化性气体后,催化剂表面吸附的一氧化碳能够优先被氧化生成二氧化碳并快速脱附,释放出被毒化的活性位点,从而恢复其催化加氢能力。将本发明所提供的方法应用于不饱和醛或酮选择加氢反应、酯类催化选择加氢反应和木质素含氧化合物氢解反应中,不仅改善了催化活性和选择性,还能提高催化剂的稳定性和寿命。此外,本发明所提供的方法还具有操作简单且重复性好的优点。(The invention discloses a method for instantly eliminating carbon monoxide poisoning of a metal catalyst in heterogeneous catalytic hydrogenation, which comprises the following steps: in the gas or liquid flow dynamic environment, when the metal catalyst is used to catalyze the heterogeneous hydrogenation reaction, a small amount of oxidizing gas is introduced into the reaction system to eliminate or prevent the carbon monoxide poisoning of the metal catalyst. The method provided by the invention is characterized in that after trace oxygen or oxidizing gas is doped into the reaction atmosphere, carbon monoxide adsorbed on the surface of the catalyst can be preferentially oxidized to generate carbon dioxide and is rapidly desorbed to release poisoned active sites, so that the catalytic hydrogenation capability of the catalyst is recovered. The method provided by the invention is applied to selective hydrogenation reaction of unsaturated aldehyde or ketone, catalytic selective hydrogenation reaction of esters and hydrogenolysis reaction of lignin oxygen-containing compounds, so that the catalytic activity and selectivity are improved, and the stability and the service life of the catalyst are improved. In addition, the method provided by the invention also has the advantages of simple operation and good repeatability.)

1. A method for instantly eliminating carbon monoxide poisoning of a metal catalyst in heterogeneous catalytic hydrogenation is characterized by comprising the following steps: in the gas or liquid flow dynamic environment, when the metal catalyst is used to catalyze the heterogeneous hydrogenation reaction, a small amount of oxidizing gas is introduced into the reaction system to eliminate or prevent the carbon monoxide poisoning of the metal catalyst.

2. The method of claim 1, wherein the metal catalyst is one or more of Fe, co, Ni, Cu, Ru, Rh, Pd, Ag, Os, Ir, Pt or Au containing catalytic hydrogenation catalyst.

3. The method for eliminating carbon monoxide poisoning of a metal catalyst in a heterogeneous catalytic hydrogenation process as claimed in claim 1, wherein the oxidizing gas is one or more of air, ozone and oxygen.

4. The use of the method of claim 1 for the catalytic selective hydrogenation of unsaturated aldehydes or ketones for the immediate elimination of carbon monoxide poisoning of metal catalysts in heterogeneous catalytic hydrogenation.

5. The use of the method of claim 1 for eliminating carbon monoxide poisoning of a metal catalyst in a heterogeneous catalytic hydrogenation process for the production of alcohols by selective hydrogenation of esters.

6. The use of the method of claim 1 for the catalytic hydrogenolysis of lignin oxygenates for the immediate elimination of carbon monoxide poisoning of metal catalysts in heterogeneous catalytic hydrogenation.

Technical Field

The invention belongs to the technical field of catalyst application, and particularly relates to a method for instantly eliminating carbon monoxide poisoning of a metal catalyst in situ in heterogeneous catalytic hydrogenation and application thereof.

Background

Catalytic reaction processes are important processes in modern industry and are key steps in the production of clean fuels and higher-order chemicals. In some catalytic Hydrogenation industrial processes, although the use of crude hydrogen as a hydrogen source has the characteristics of simple industrial device, higher economy and the like, a small amount of carbon monoxide (from tens to thousands of ppm) contained in crude hydrogen prepared from carbon-based raw materials can cause the inactivation of a Hydrogenation metal catalyst because of strong interaction between the carbon monoxide and a metal active center, and quickly occupy a catalytic active site in the catalytic reaction process, so that reactant molecules cannot be adsorbed on the surface of a catalyst to cause poisoning inactivation (b.campo, c.petit, a.mar ia, Hydrogenation o, etc.)f crotonaldehyde on different Au/CeO₂catalysts.[J]J.Catal.,2008,254(1) 71-78; waghray, D.G.Blackmond, isolated spectra carbon monoxide pic studios of the adsorption and reaction of 3-methyl-2-nuclear over alkali-promoted Ru/SiO₂ catalysts.[J]J.Phys.chem.,1993,97(22): 6002-6006). Thus, modern catalytic hydrogenation processes typically add expensive and complex hydrogen purification systems to produce high purity hydrogen as a hydrogen source (x.c. lan, k.z.xue, t.f. wang, carbon monoxide bound synthetic and steric effects for high purity selective hydrogenation [ J]J.Catal.,2019,372: 49-60; K.H.Doster, C.P.O' Brien, F.Ivars-Barcelo, et al, spectrometers carbon monoxide ntrol selection in surface chemistry, and vironement partial hydrogenation over Pd [ J].J.Am.Chem.Soc.,2015,137(42):13496-13502.)。

The development of a novel technology to improve the carbon monoxide tolerance of a metal catalyst and directly utilize crude hydrogen to carry out efficient catalytic hydrogenation, thereby reducing the hydrogenation cost and simplifying industrial devices is a major challenge in the research field.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a method for instantly eliminating or preventing carbon monoxide poisoning of a metal catalyst in heterogeneous catalytic hydrogenation and an application thereof, and the solution is as follows:

a method for instantly eliminating carbon monoxide poisoning of a metal catalyst in heterogeneous catalytic hydrogenation is characterized by comprising the following steps: in the catalytic hydrogenation reaction using the metal catalyst in a gas or liquid flow dynamic environment, a small amount of oxidizing gas is introduced into the reaction system to help eliminate or prevent carbon monoxide poisoning of the metal catalyst.

Preferably, the metal catalyst is one or more of a combination of catalytic hydrogenation catalysts comprising Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Os, Ir, Pt or Au.

Preferably, the oxidizing gas may be one or more of air, ozone or oxygen.

The method for instantly eliminating the carbon monoxide poisoning of the metal catalyst in the heterogeneous catalytic hydrogenation is applied to catalyzing the selective hydrogenation of alcohol of alpha and beta-unsaturated aldehyde.

The method for instantly eliminating the carbon monoxide poisoning of the metal catalyst in the heterogeneous catalytic hydrogenation is applied to the preparation of alcohol by catalyzing selective hydrogenation of esters.

The method for instantly eliminating the carbon monoxide poisoning of the metal catalyst in the heterogeneous catalytic hydrogenation is applied to catalyzing the hydrogenolysis reaction of the lignin oxygen-containing compound.

The specific principle of the invention is as follows:

the metal active center of the metal catalyst has adsorption and activation capacities and differences on carbon-carbon double bonds, carbon-oxygen double bonds and carbon-nitrogen double bonds contained in a hydrogenation reaction substrate, and the differences are the root causes of the occurrence of catalytic hydrogenation and the differences of product selectivity. When carbon monoxide existing in a reaction system is strongly adsorbed on a metal active center, the occupied catalytic active sites can not adsorb and activate a hydrogenation substrate any more, so that the catalytic hydrogenation reaction can not be smoothly carried out, and the metal catalyst is poisoned and inactivated. Carbon monoxide adsorbed on the metal catalyst is difficult to desorb at a lower temperature (<423K), hydrogenation reaction can not be carried out to generate water, methane and the like, and the catalytic active center is difficult to recover. After a small amount of oxygen or oxidizing gas is doped into the reaction atmosphere, carbon monoxide adsorbed on the surface can be oxidized preferentially to generate carbon dioxide and is desorbed rapidly to release poisoned active sites, so that the catalytic hydrogenation capacity is recovered. Therefore, the principle of the invention is to provide a brand-new method for eliminating the active site occupying substance by doping a trace amount of oxidizing gas into the atmosphere of a reaction system and carrying out in-situ oxidation, so that the catalytic hydrogenation reaction is ensured to be smoothly and continuously carried out, and no obvious inactivation phenomenon is found in the evaluation process of hundreds of hours.

The invention has the advantages that:

(1) the method for instantly eliminating the carbon monoxide poisoning of the metal catalyst in the heterogeneous catalytic hydrogenation provided by the invention can be used for eliminating the active site occupiant by in-situ oxidation by doping a small amount of oxidizing gas into the reaction system atmosphere, thereby not only improving the activity and selectivity of the catalytic hydrogenation, but also prolonging the service life of the catalyst.

(2) The method for instantly eliminating the carbon monoxide poisoning of the metal catalyst in the heterogeneous catalytic hydrogenation has the advantages of simple operation and good repeatability.

(3) The method for instantly eliminating the carbon monoxide poisoning of the metal catalyst in the heterogeneous catalytic hydrogenation provided by the invention is used for obviously improving the conversion rate and the selectivity when the alcohol is prepared by ester catalytic selective hydrogenation and the hydrogenolysis reaction of lignin oxygen-containing compounds.

Detailed Description

The present invention will be described in further detail with reference to examples. It should also be understood that the following examples are only for illustrating the present invention and should not be construed as limiting the scope of the present invention, and the specific mass ratio, reaction time, temperature and other process parameters in the examples are only an example of suitable ranges, and that the insubstantial modifications and adjustments made by those skilled in the art according to the above disclosure are included in the scope of the present invention. The examples, where specific techniques or conditions are not indicated, are performed according to the techniques or conditions described in the literature in the art or according to the product specifications. The reagents or instruments used are not indicated by manufacturers, and are all conventional products which can be purchased in the market.

In all examples, the conversion and selectivity were calculated as follows:

substrate conversion (%). The moles of substrate reacted/moles of substrate fed x 100%

Product selectivity (%). The product moles generated/reaction substrate moles 100%

Example 1

The preparation steps of the catalyst are as follows:

1.0g of iridium acetylacetonate Ir (acac)₃Dissolving in acetylacetone to obtain 3.9264mg/mL Ir (acac)₃The precursor solution of (1); 0.190g of SiO₂The vehicle was charged to 2.547mL Ir (acac)₃Performing ultrasonic treatment on the precursor solution after stirring the obtained mixture for 20min, transferring the mixture to a dark place, standing for 24h, then placing the mixture into a drying oven to dry for 3h at 383K, finally placing the obtained solid into a muffle furnace to calcine, and increasing the speed at 2K/minHeating to 773K and maintaining for 3h, cooling to obtain 0.2g of 5% Ir/SiO₂A catalyst.

The specific reaction steps for preparing the crotyl alcohol by catalyzing the gas-phase selective hydrogenation of the crotonaldehyde are as follows: the catalyst activity evaluation is carried out on a fixed bed device at normal pressure, and 25mg of 5 percent Ir/SiO₂The catalyst was loaded into a quartz reaction tube at a high purity of H of 10mL/min₂The temperature is increased to 773K at the rate of 20K/min under the air flow for reduction for 0.5h for catalyst activation; then high-purity H is introduced₂Reacting with crotonaldehyde steam, wherein the ratio of hydrogen to aldehyde is 80, the total gas flow is 10mL/min, the reaction pressure is normal pressure, and the reaction temperature is 373K. Gaseous substances coming out of the bottom of the reactor enter a gas chromatograph (GC-2010, Shimadzu) provided with a hydrogen ion flame detector through a heat preservation pipeline (393K) for online quantitative analysis, and stable data after 120min are taken for comparison. The evaluation results are shown in Table 1, 5% Ir/SiO₂When the catalyst uses high-purity hydrogen as a hydrogen source, the conversion rate of crotonaldehyde is 52.3 percent, and the selectivity of unsaturated alcohol crotyl alcohol is 92.3 percent.

Example 2

The preparation procedure of the catalyst was the same as that of example 1, and the reaction conditions for producing crotyl alcohol by catalytic gas-phase selective hydrogenation of crotonaldehyde were the same as in example 1 except that high-purity H was used₂Is changed into H containing trace carbon monoxide₂The conditions of the mixed gas (carbon monoxide concentration 100ppm) were the same as in example 1. The results of the evaluation are shown in Table 1, and when hydrogen gas similar to crude hydrogen (containing a low concentration of carbon monoxide) was used as a hydrogen source, the conversion of crotonaldehyde was only 1.2%, and the selectivity of crotyl alcohol as a product was 72.5%.

Example 3

The catalyst deactivated by carbon monoxide poisoning in example 2 was activated with an activating gas containing O₂And H₂Mixed gas (O)₂The concentration of (1) is 0.02 percent), the activation temperature is 423K, and the activation time is 2 h; the reaction conditions for producing crotyl alcohol by gas phase selective hydrogenation of crotonaldehyde after activation were the same as in example 1, and the reaction results are shown in Table 1, wherein the conversion of crotonaldehyde was 48.1% and the selectivity of crotyl alcohol as a product was 91.5%.

Example 4

The preparation steps of the catalyst are the same as example 1, and the reaction conditions for preparing crotyl alcohol by catalyzing crotonaldehyde gas-phase selective hydrogenation are the same as example 1 except that the reaction gas is high-purity H₂Change into trace of carbon monoxide and O₂And H₂Gas mixture (carbon monoxide concentration 100ppm, O)₂0.02%) under the same conditions as in example 1; the reaction results are shown in Table 1, with crotonaldehyde conversion of 59.1% and crotyl alcohol product selectivity of 92.4%.

TABLE 1 Ir/SiO in different reaction atmospheres₂Performance of catalytic selective hydrogenation of crotonaldehyde

Reaction conditions are as follows: the catalyst dosage is 0.025g, the reaction pressure is normal pressure, the reaction temperature is 373K, the hydrogen-aldehyde ratio is 80, and the total flow is 10 mL/min.

As can be seen from Table 1, Ir/SiO₂The conversion rate of 48.1 percent can be achieved under the atmosphere of high-purity hydrogen, but after a trace amount of carbon monoxide is doped into a reaction system, the phenomenon of deactivation occurs immediately, and the conversion rate is directly reduced to 1.2 percent, which indicates that carbon monoxide as a strong adsorption species can poison active sites and cannot be desorbed to leave the surface of the catalyst. The deactivated catalyst is activated by using hydrogen-oxygen mixed gas with low oxygen concentration under 423K, the activity is completely recovered after the treatment, and the conversion rate reaches 52.3 percent. Directly using CO and O at 373K₂And H₂Mixed gas (CO concentration 100ppm, O)₂0.02%) as raw material gas, the conversion rate of crotonaldehyde on the same catalyst can be up to 59.1%, the selectivity of crotyl alcohol is 92.4%, its performance is superior to that of high-purity hydrogen reaction system, and its activity and selectivity are not reduced after more than 48 hr.

Example 5

The catalyst was prepared in the same manner as in example 1, and the conditions for the gas phase selective hydrogenation reaction were as in example 1 except that crotonaldehyde was changed to acrolein and the other conditions were the same. The reaction results are shown in Table 2, the conversion of acrolein is 29.4%, and the selectivity of the product propenol is 29.3%.

Example 6

The catalyst was prepared in the same manner as in example 1, and the conditions for the gas phase selective hydrogenation reaction were as in example 2 except that crotonaldehyde was changed to acrolein and the other conditions were the same. The reaction results are shown in Table 2, the conversion of acrolein is 2.6%, and the selectivity of the product propenol is 12.3%.

Example 7

The catalyst deactivated by carbon monoxide poisoning in example 6 was subjected to oxygen-supplying activation treatment using an activating gas containing O₂And H₂Mixed gas (O)₂The concentration of (1) is 0.02 percent), the temperature is 373K, and the time is 2 h; the conditions for the gas phase selective hydrogenation reaction were as in example 3, except that crotonaldehyde was changed to acrolein and the remaining conditions were the same. The reaction results are shown in Table 2, the catalytic performance is not obviously improved after treatment, the conversion rate of the acrolein is 3.7 percent, and the selectivity of the product allyl alcohol is 13.6 percent.

Example 8

The catalyst was prepared in the same manner as in example 1, and the conditions for the gas phase selective hydrogenation reaction were as in example 4 except that crotonaldehyde was changed to acrolein and the remaining conditions were the same. The reaction results are shown in Table 2, the conversion of acrolein is 34.3%, and the selectivity of the product propenol is 24.0%.

TABLE 2 Ir/SiO in different reaction atmospheres₂Performance of catalytic acrolein selective hydrogenation

Reaction conditions are as follows: the catalyst dosage is 0.025g, the reaction pressure is normal pressure, the reaction temperature is 373K, the hydrogen-aldehyde ratio is 80, and the total flow is 10 mL/min.

As can be seen from Table 2, Ir/SiO for the Selective hydrogenation of acrolein₂When the catalyst uses high-purity hydrogen as a hydrogen source, the conversion rate can reach 29.4 percent, and the selectivity of the allyl alcohol is 29.3 percent; but after a trace amount of carbon monoxide is doped into the reaction system, the obvious activity reduction occurs, the conversion rate is reduced to 2.6 percent, and the carbon monoxide is provedAs a strongly adsorbed species, poison the active sites and inhibit the catalytic reaction. When a small amount of O is mixed into hydrogen containing CO₂The obtained product is used as a hydrogen source for hydrogenolysis reaction, so that the catalytic activity is obviously improved, the conversion rate is increased to 34.3 percent, and the CO poisoning phenomenon is eliminated.

Example 9

The preparation steps of the catalyst are as follows:

4.6g of copper nitrate Cu (NO)₃)₂Dissolving in 150mL of deionized water, adding 15.7g of 40% silica sol and 6.5g of urea into a copper nitrate solution, stirring the obtained mixture, heating and stirring at 353K in a constant-temperature tank for reflux treatment for 12 hours, centrifugally washing the obtained solid for 3 times, drying the solid in a drying oven at 383K for 6 hours, finally putting the obtained solid into a muffle furnace for calcination, heating to 623K at the speed of 2K/min, keeping the temperature for 2 hours, and cooling to obtain 7.9g of 20% Cu/SiO₂A catalyst precursor.

The activation treatment steps of the catalyst are as follows: placing a proper amount of catalyst precursor in a reactor, introducing high-purity hydrogen, heating to 623K, reducing for 4h at the hydrogen flow rate of 100mL/min, and then reducing to 453K in the high-purity hydrogen atmosphere to start catalytic hydrogenation reaction. The evaluation steps of the catalytic performance of the ethylene glycol prepared by selective hydrogenation of dimethyl oxalate comprise: the filling amount of the catalyst is 0.5g, the reaction temperature is 453K, the reaction pressure is 3Mpa, the flow rate of high-purity hydrogen is 80mL/min, meanwhile, a high-pressure constant flow pump is used for pumping dimethyl oxalate-methanol solution with the concentration of 0.02g/mL into the reactor, the mass flow rate of the dimethyl oxalate is 0.75g/h, the ratio of hydrogen to the dimethyl oxalate is 80, substances discharged from the bottom of the reactor are subjected to heat preservation by 473K and then enter a gas chromatography (GC-2010, Shimadzu) provided with a hydrogen ion flame detector for online quantitative analysis, and stable data after 120min are taken for comparison. The reaction results are shown in Table 3, the conversion of dimethyl oxalate is 65.4%, and the selectivity of the product ethylene glycol is 39.2%.

Example 10

The catalyst was prepared in the same manner as in example 9, and the conditions for the selective hydrogenation of dimethyl oxalate were as in example 9, except that the reaction gas was high-purity H₂Is changed into H containing trace carbon monoxide₂The conditions of the mixed gas (carbon monoxide concentration 100ppm) were the same as in example 9; the reaction results are shown in Table 3, the conversion of dimethyl oxalate was 12.3%, and the selectivity of the product, ethylene glycol, was 23.6%.

Example 11

The catalyst deactivated by carbon monoxide poisoning in example 10 was activated with an activating gas containing O₂And H₂Mixed gas (O)₂The concentration of (A) is 0.02 percent), the activation temperature is 473K, and the activation time is 2 h; the reaction conditions for catalyzing the selective hydrogenation of dimethyl oxalate after the activation are the same as those of example 9, and the reaction results are shown in Table 3, wherein the conversion rate of dimethyl oxalate is 83.2%, and the selectivity of the product ethylene glycol is 53.6%.

Example 12

The catalyst was prepared in the same manner as in example 9, and the conditions for the selective hydrogenation of dimethyl oxalate were as in example 9, except that the reaction gas was high-purity H₂Change into trace of carbon monoxide and O₂And H₂Gas mixture (carbon monoxide concentration 100ppm, O)₂The concentration of (b) was 0.02%), and the other conditions were the same as in example 9. The reaction results are shown in Table 3, the conversion of dimethyl oxalate was 89.6%, and the selectivity of the product, ethylene glycol, was 75.8%.

TABLE 3 Cu/SiO in different atmospheres₂Performance of catalyzing selective hydrogenation of dimethyl oxalate

Reaction conditions are as follows: the loading of the catalyst is 0.5g, the reaction temperature is 453K, the reaction pressure is 3Mpa, the mass flow rate of the dimethyl oxalate is 0.75g/h, and the ratio of hydrogen to the dimethyl oxalate is 80.

As can be seen from Table 3, Cu/SiO for the reaction of selective hydrogenation of dimethyl oxalate to ethylene glycol₂When the catalyst uses high-purity hydrogen as a hydrogen source, the conversion rate of 85.3 percent can be achieved, and the selectivity of ethylene glycol is 58.5 percent; but after a trace amount of carbon monoxide is doped into the reaction system, the obvious activity reduction occurs, the conversion rate is reduced to 12.3 percent, and the carbon monoxide serving as a strong adsorption species can be poisonedThe active sites inhibit the catalytic reaction. When a small amount of O is mixed into hydrogen containing CO₂The obtained product is used as a hydrogen source for hydrogenolysis reaction, so that the catalytic activity is obviously improved, the conversion rate is increased to 89.6%, and the CO poisoning phenomenon is eliminated.

Example 13

The preparation steps of the catalyst are as follows:

2.5g of Ni (NO)₃)₂·6H₂O and 3.6g Fe (NO)₃)₃·9H₂Dissolving O in 100mL of deionized water, adding 9g of Carbon Nanotubes (CNTs) into the solution, performing ultrasonic dispersion for 30min, then performing reflux stirring for 2h at 353K, drying the obtained mixture at 373K, and roasting the obtained black solid for 4h at 573K to obtain the NiFe/CNTs catalyst.

The specific reaction steps are as follows: 0.5g of catalyst was charged into a high-pressure reactor, the front and rear of the catalyst were packed with quartz wool, and 5g of quartz sand was added to the top. Introducing high-purity hydrogen to carry out pre-reduction at 575K, and adjusting the temperature to 555K after 2h to carry out performance evaluation of the guaiacol hydrogenolysis reaction. During the hydrogenolysis reaction, guaiacol raw material liquid is conveyed to a vaporizer for gasification by a high-pressure constant flow pump, then enters a high-pressure reactor together with hydrogen to contact with a catalyst for hydrogenolysis reaction, and substances discharged from the tail end of the reactor enter two chromatographs (Agilent 7890A equipped with an FID detector and GC2060 equipped with a TCD detector) equipped with automatic sampling valves through a heat insulation pipeline for product analysis. The experimental data set forth in table 4 were obtained after a two hour reaction to steady state and the conversion of guaiacol and the selectivity of each product were calculated using calibration factor normalization. The results of the guaiacol hydrogenolysis reaction are shown in table 4: the conversion of guaiacol was 79.0% and the selectivity of the products cyclohexane and cyclohexanol was 65.0 and 28.5%, respectively.

Example 14

The catalyst was prepared as in example 13, and the conditions for the guaiacol catalyzed hydrogenolysis reaction were as in example 13, except that the reaction gas was purified to high purity H₂Is changed into H containing trace carbon monoxide₂The conditions of the mixed gas (carbon monoxide concentration: 100ppm) were the same as in example 13. The reaction results are shown in Table 4: conversion of guaiacol35.8% and the selectivities for the products cyclohexane and cyclohexanol were 31.2% and 50.9%, respectively.

Example 15

The catalyst was prepared as in example 13, and the conditions for the guaiacol catalyzed hydrogenolysis reaction were as in example 13, except that the reaction gas was purified to high purity H₂Change into trace of carbon monoxide and O₂And H₂Gas mixture (carbon monoxide concentration 100ppm, O)₂The concentration of (2) was 0.02%), and the other conditions were the same as in example 13. The reaction results are shown in Table 4: the conversion of guaiacol was 85.9% and the selectivity of the products cyclohexane and cyclohexanol was 77.9% and 18.8%, respectively.

As can be seen from Table 4, for the guaiacol catalytic hydrogenolysis reaction, when high-purity hydrogen is used as a hydrogen source, NiFe/CNTs can reach 79.0% of conversion rate, but after trace carbon monoxide is doped in the reaction system, the obvious activity reduction occurs, the conversion rate is reduced to 35.8%, and the fact that carbon monoxide as a strong adsorption species poisons active sites to inhibit the catalytic reaction is shown. When a small amount of O is mixed into hydrogen containing CO₂The obtained product is used as a hydrogen source for hydrogenolysis reaction, so that the catalytic activity is obviously improved, the conversion rate is increased to 85.9 percent, and the CO poisoning phenomenon is eliminated.

TABLE 4 influence of carbon monoxide on the performance of the NiFe/CNTs catalyzed guaiacol hydrogenolysis reaction

Reaction conditions are as follows: the catalyst loading was 0.5g, the reaction pressure was 3MPa, the hydrogen/guaiacol ratio was 50, the reaction temperature was 553K, and the total flow was 60 mL/min.