Continuous process for the conversion of carbohydrate sources and / or polyols into alcoholic compounds

Abstract

The present application relates to a kind of continuous method for converting carbohydrate source and / or polyhydric alcohol into alcohol compound of equal carbon number and / or less carbon number, especially dihydric alcohol and / or monohydric alcohol and / or polyhydric alcohol containing at least three hydroxyl groups, which can realize economic, simple and stable production capacity, uninterrupted reaction of continuous production, while improving the security and convenience of operation.

Description

Technical Field

[0001] This invention relates to a continuous method for converting carbohydrate sources and / or polyols into alcohols with the number of carbons and / or fewer carbons, particularly diols and / or monools and / or polyols containing at least three hydroxyl groups. Background Technology

[0002] In the process of converting carbohydrate sources and / or polyols into alcohols with equal and / or fewer carbon numbers, an aqueous solvent is used, combined with a hydrogenation catalyst and a tungsten-containing catalyst.

[0003] Among them, tungsten-containing catalysts contain one or more tungsten-containing compounds, complexes, or elemental materials. These substances are transformed into tungsten deposits during hydrolysis reactions, and the reaction rate is accelerated, especially under high temperature and acidic conditions. These deposits accumulate in the reaction system through adsorption, coordination, or deposition, which not only clogs the catalyst pores and reduces the hydrogenation activity of heterogeneous hydrogenation catalysts, but also gradually reduces the gas-solid-liquid three-phase mass transfer efficiency with increasing solid content.

[0004] Deactivation of hydrogenation catalysts not only comes from heterogeneous tungsten deposition, but also from the accumulation of polyhydroxyl structures of carbohydrate compounds, including reactant carbohydrate molecules and product polyols, on the catalyst surface, metal oxidation, and dissolution of catalyst components. In particular, when the amount of deposited tungsten increases, the deposited tungsten, as a Lewis acid catalyst, will accelerate polymer formation.

[0005] WO2020055831A1 proposes a method to add one or more reagents that inhibit tungsten precipitation to the reactor before or simultaneously with the addition of a tungsten-containing reverse aldol catalyst. This means that the tungsten-containing catalyst and inhibitors, such as buffer systems of oxygen-containing organic acids and their corresponding alkali metal conjugate bases or organic oxygen-containing compounds, are added continuously during the reaction. This method not only increases the cost of inhibitor consumption, but also the use of organic oxygen-containing compounds as inhibitors may result in their oxidation to organic acids under reaction conditions, which could actually increase tungsten precipitation. Furthermore, using alkali metal bases requires very high concentrations to completely inhibit tungsten deposition; for example, the examples used very low glucose concentrations and relatively high NaHCO3 concentrations, with NaHCO3 accounting for as much as 4.5% of the glucose mass, leading to high buffer consumption and removal costs. However, due to the low glucose concentration, the concentration of the resulting organic acid is also low, with an actual NaHCO3 concentration of only 450 ppm. In industrial production, glucose concentrations are often higher, therefore the method in WO2020055831A1 is not suitable.

[0006] WO2019175365A1 proposes a method for regenerating a used heterogeneous catalyst by removing deposited tungsten material, with a portion of the regenerated catalyst recycled back to the reactor. The regeneration process is carried out using a scrubbing agent in the absence of hydrogen, and the hydrogenation reaction is completely stopped during regeneration. Therefore, both in-situ and ex-situ operations will affect the effective utilization time of the reactor and increase the energy consumption of subsequent scrubbing liquid separation. Ex-situ regeneration methods also require additional filtration and regeneration units, increasing initial equipment investment and operating costs.

[0007] WO2019175362A1 employs a supported heterogeneous catalyst. It maintains ethylene glycol selectivity by removing spent catalyst with excessive tungsten deposits and continuously or periodically adding additional heterogeneous catalyst to the reactor. This method involves frequent operations. Because it removes catalyst containing tungsten deposits, it is difficult to determine the mass of the removed catalyst in the reactor, thus making it difficult to determine the amount of catalyst to be added. Furthermore, additional equipment and processes are required outside the reaction system to separate the tungsten from the removed catalyst.

[0008] WO2021061969A1 proposed using a control model that correlates the concentration of by-products or intermediates or tracers with the performance of catalysts, adjusting the feed rate or concentration or adding catalyst to maintain catalytic performance. However, reducing the feed rate or concentration will reduce the production capacity of the target product, and adding catalyst cannot solve the problem of tungsten deposition accumulation.

[0009] Therefore, the inventors of this invention seek a continuous and stable method for converting carbohydrate sources and / or polyols into alcohol compounds with equal and / or fewer carbon numbers, thereby achieving economical, simple, and stable continuous production while improving operational safety and convenience. Summary of the Invention

[0010] The purpose of this invention is to provide a continuous method for converting carbohydrate sources and / or polyols into alcohol compounds with equal and / or fewer carbon numbers, particularly diols and / or monools and / or polyols containing at least three hydroxyl groups. This method enables economical, simple, and stable production capacity with uninterrupted reaction, while improving operational safety and convenience.

[0011] Specifically, the present invention relates to a continuous method for converting carbohydrate sources and / or polyols into alcohol compounds with the same and / or fewer carbon numbers, comprising the following steps:

[0012] 1) To continuously react one or more carbohydrate sources and / or polyols in a reactor in the presence of hydrogen, a heterogeneous hydrogenation catalyst and a homogeneous tungsten-containing catalyst to obtain a reaction mixture containing alcohols with equal and / or fewer carbon numbers;

[0013] 2) a) During continuous stable operation, when the reaction time reaches at least 50 hours, the addition of the homogeneous tungsten-containing catalyst shall be stopped, and the addition of a tungsten-free alkaline catalyst shall begin, and / or

[0014] During continuous stable operation, when the pH of the reaction mixture decreases by at least 0.1 and / or the concentration change of certain products in the reaction mixture is at least 0.5% of their original concentration and / or the tungsten deposition is at least 1% by weight of the catalyst, the addition of the homogeneous tungsten-containing catalyst shall be stopped, and the addition of a tungsten-free alkaline catalyst shall begin.

[0015] When selecting the conditions for "stopping the addition of the homogeneous tungsten-containing catalyst", the first condition that occurs shall prevail.

[0016] b) After adding the tungsten-free alkaline catalyst for at least 1 hour and / or the pH of the reaction mixture obtained in a) rises by at least 0.1 and / or the concentration of some products changes again by at least 3% of their original concentration and / or at least 10% of the deposited tungsten is converted to homogeneous tungsten-containing catalyst and / or when the tungsten atom concentration in the reaction mixture shows a decreasing trend, and the decrease is at least 1% by weight of the maximum tungsten atom concentration in the reaction mixture in step a), stop adding the tungsten-free alkaline catalyst and add the homogeneous tungsten-containing catalyst again.

[0017] When selecting the conditions for "stopping the addition of tungsten-free alkaline catalyst", the first condition that occurs shall prevail.

[0018] 3) Optionally, the heterogeneous catalyst in the reaction mixture obtained in step 2) is partially replaced with a new heterogeneous catalyst.

[0019] In some embodiments, in step 1) above, the homogeneous tungsten-containing catalyst may be in the form of a mixture of a homogeneous tungsten-containing catalyst and one or more tungsten-free basic catalysts.

[0020] In steps 2) and 3) above, carbohydrate sources and / or polyols and hydrogen are continuously fed to ensure the continuity of the reaction.

[0021] The term "alcohols with the same and / or fewer carbon atoms" refers to alcohols whose carbon number is the same as and / or fewer than that of the raw material (i.e., carbohydrate source and / or polyol). Specifically, alcohols with the same and / or fewer carbon atoms refer to diols and / or monools and / or polyols containing at least three hydroxyl groups.

[0022] The carbohydrate source is defined as a substance that provides carbohydrates. Preferably, the carbohydrate source should contain one or more types of carbohydrates, such as polysaccharides, oligosaccharides, disaccharides, monosaccharides, and / or their derivatives (such as sugar alcohols, glycosides, sugar acids, etc.), or mixtures thereof. More preferably, the carbohydrate source contains glucose, xylose, fructose, sucrose, or combinations thereof, or is composed of them.

[0023] The polyols mentioned above refer to organic compounds whose molecules contain at least two hydroxyl groups, preferably at least three hydroxyl groups. Preferably, the polyols include, but are not limited to: glycerol, sorbitol, mannitol, xylitol, diethylene glycol, triethylene glycol, etc., or combinations thereof, or compositions thereof.

[0024] Suitable examples of carbohydrate sources and / or polyols are preferably sustainably available carbohydrate sources and / or polyols that are wholly or largely derived from, derived from, or synthesized from bioproducts, renewable agricultural materials, or forestry materials. Pretreatment steps may be required before applying these raw materials to extract and purify the desired materials, while removing any impurities that could interfere with subsequent processing.

[0025] In some embodiments, the concentration of the carbohydrate source and / or polyols in the total liquid feed is 10-90% by weight, preferably 30-80% by weight (wherein the weight of the carbohydrate source and / or polyols is on a dry basis). Preferably, the pH of the total liquid feed containing the carbohydrate source and / or polyols is 3-9.

[0026] In some embodiments, the carbohydrate source and / or polyols may be introduced into the reactor along with at least a portion of the solvent. For example, the carbohydrate source and / or polyols are partially or completely dissolved in the solvent. Preferred solvents include aqueous media, organic media containing alkylene glycols, water, C1-C6 alcohols or polyols containing at least two hydroxyl groups (including sugar alcohols), organic acids, ethers and other suitable organic compounds, or mixtures thereof, which are capable of effectively dissolving a variety of carbohydrate sources and / or polyols. In some cases, the carbohydrate source and / or polyols may also be added to the reactor in slurry form, such as an aqueous mixture of water and hemicellulose, sugars, glucose and / or starch.

[0027] The heterogeneous hydrogenation catalyst is insoluble in the total liquid feed, thus forming a heterogeneous form.

[0028] The heterogeneous hydrogenation catalyst can be used in conjunction with a heterogeneous tungsten-containing catalyst. The heterogeneous tungsten-containing catalyst is insoluble in the total liquid feed.

[0029] The heterogeneous hydrogenation catalyst can be a supported catalyst or an unsupported catalyst, preferably comprising one or more metals from groups 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, and 15 of the periodic table, such as magnesium, boron, aluminum, germanium, tin, antimony, selenium, lanthanum, cerium, samarium, titanium, zirconium, vanadium, niobium, chromium, molybdenum, tungsten, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, zinc, etc., or combinations thereof. These metals can be present in metallic form, alloy form, hydride, oxide, or other compound form. For example, in some embodiments, these metals are present in a partially tungstenized form. The heterogeneous hydrogenation catalyst is, for example, a framework-type nickel-based composite alloy catalyst.

[0030] The heterogeneous hydrogenation catalyst can be stored in a suitable solvent, including, for example, water, at least one base compound, at least one alcohol compound, at least one hydrocarbon compound, at least one ether compound, at least one ketone compound, at least one acid compound, or a mixture of the above components, and / or a reaction mixture removed from the reactor after the heterogeneous hydrogenation catalyst has been removed, and / or a reaction mixture removed from the reactor after the heterogeneous hydrogenation catalyst and the homogeneous tungsten-containing catalyst have been removed. Preferably, the pH of the storage system for the heterogeneous hydrogenation catalyst is 4-12, more preferably 5-10, and more preferably 5-9.

[0031] In some embodiments, the concentration of the heterogeneous hydrogenation catalyst in the reactor is at least 50 g / L, preferably at least 110 g / L, and more preferably at least 130 g / L (wherein the catalyst weight is based on a dry basis and the volume is based on the volume of the liquid medium in the reactor).

[0032] In some embodiments, the processing capacity per kilogram of heterogeneous hydrogenation catalyst is at least 0.3 kg per hour, preferably at least 0.4 kg, more preferably at least 0.5 kg of carbohydrate source and / or polyol (wherein the weight of the catalyst is based on dry-based catalyst, and the weight of the carbohydrate source and / or polyol is based on dry-based carbohydrate source and / or polyol).

[0033] In some embodiments, the processing capacity per cubic meter of reactor is at least 50 kg, preferably at least 60 kg, more preferably at least 80 kg of carbohydrate sources and / or polyols per hour (wherein the volume is the volume of the liquid medium in the reactor, and the weight of the carbohydrate sources and / or polyols is the dry basis of the carbohydrate sources and / or polyols).

[0034] The heterogeneous tungsten-containing catalyst and the homogeneous tungsten-containing catalyst can each independently include, but are not limited to, tungsten compounds, complexes, or elemental forms, and can be used alone or in combination. Examples include tungsten carbides, nitrides, phosphides, oxides, sulfides, chlorides, hydroxides, tungsten bronze, tungstic acid and polytungstic acid, tungstates, metatungstic acid, metatungstates, paratungstic acid, paratungstates, peroxytungstic acid, peroxytungstates, tungsten heteropolyacids, etc. Preferably, tungsten oxides, tungsten bronze, tungstic acid and polytungstic acid, sodium tungstate, and dissolved tungstate ions, metatungstate ions, and paratungstate ions are used.

[0035] The homogeneous tungsten-containing catalyst refers to a tungsten-containing catalyst that can be dissolved in a solvent to form a homogeneous form. Preferred solvents include aqueous media, organic media containing alkylene glycols, water, C1-C6 alcohols or polyols (including sugar alcohols) containing at least two hydroxyl groups, organic acids, ethers and other suitable organic compounds, or mixtures thereof.

[0036] In some embodiments, the weight ratio of the tungsten-containing catalyst (based on tungsten atoms) to the carbohydrate source and / or polyols is >0-10, preferably 0.0002-9, more preferably 0.0003-8 (wherein the weight of the carbohydrate source and / or polyols is based on dry basis).

[0037] The tungsten-free alkaline catalyst may include one or more organic bases, inorganic bases, and salts that are alkaline after dissolution, such as one or more selected from ammonium hydroxide, alkali metal or alkaline earth metal hydroxides, alkali metal and alkaline earth metal salts of carbonic acid or carboxylic acid or combinations thereof, alkali metal and alkaline earth metal salts of phosphoric acid, zinc salts of zinc carbonate and carboxylic acid, and / or one or more selected from organic bases such as amine compounds and alkali metal salts of alcohols, more preferably sodium hydroxide, sodium carbonate, sodium bicarbonate or combinations thereof.

[0038] The alkali concentration and dosage of the tungsten-free alkaline catalyst should ensure that it can exert a highly efficient catalytic effect during the reaction process without corroding or damaging the reactor material, while ensuring that the structure and activity of the catalyst itself are not affected.

[0039] The tungsten-free alkaline catalyst can be used in a solvent, either partially or completely dissolved. Preferably, the tungsten-free alkaline catalyst is used in the form of a homogeneous alkaline catalyst. Preferred solvents include aqueous media, organic media containing alkylene glycols, water, C1-C6 alcohols or polyols (including sugar alcohols) containing at least two hydroxyl groups, organic acids, ethers and other suitable organic compounds, or mixtures thereof.

[0040] In steps 2)a) and b), one or more of the conditions can be detected.

[0041] In some implementations, step 2) may be performed at least once, preferably at least twice.

[0042] In step 2), "certain products" refers to compounds that can be detected and thereby monitored in relation to the reaction process, such as C1-C6 alcohols and / or organic acids. C1-C6 alcohols may include methanol, ethanol, ethylene glycol, propylene glycol, butanediol, glycerol, butanetetrol, sorbitol, etc. Organic acids may include formic acid, acetic acid, lactic acid, glycolic acid, glyceric acid, etc.

[0043] Preferably, in step 2)a), the reaction time reaches at least 100 hours.

[0044] Preferably, in step 2)a), the pH of the reaction mixture decreases by at least 0.2, more preferably by at least 0.3.

[0045] Preferably, in step 2)a), the concentration change of certain products in the reaction mixture is at least 0.7% of their original concentration, more preferably at least 0.9% of their original concentration.

[0046] Preferably, in step 2)a), the amount of tungsten deposited is at least 5% by weight of the catalyst, more preferably at least 7% by weight, and even more preferably at least 9% by weight.

[0047] Preferably, in step 2)b), the addition of the tungsten-free alkaline catalyst is stopped after at least 1.2 hours, preferably at least 1.5 hours.

[0048] Preferably, in step 2)b), the addition of a tungsten-free alkaline catalyst is stopped when the pH of the reaction mixture rises by at least 0.2, more preferably at least 0.4, and even more preferably at least 0.6.

[0049] Preferably, in step 2)b), the addition of the tungsten-free alkaline catalyst is stopped when the concentration of certain products changes by at least 5% of their original concentration, more preferably at least 7% of their original concentration.

[0050] Preferably, in step 2)b), when at least 12%, more preferably at least 15%, of the deposited tungsten is converted into a homogeneous tungsten-containing catalyst, the addition of a tungsten-free alkaline catalyst is stopped.

[0051] Preferably, in step 2)b), when the concentration of tungsten atoms in the reaction mixture shows a decreasing trend, and the decrease is at least 5% by weight of the maximum concentration of tungsten atoms in the reaction mixture in step a), more preferably at least 10% by weight of the maximum concentration of tungsten atoms in the reaction mixture in step a), the addition of tungsten-free alkaline catalyst is stopped.

[0052] Because the activity of heterogeneous hydrogenation catalysts decreases with prolonged use, they must be replaced with new homogeneous hydrogenation catalysts to maintain the yield of the target alcohol compound. Preferably, in step 3), the reaction mixture containing the heterogeneous hydrogenation catalyst is replaced with a mixture containing new heterogeneous catalyst, wherein the volume or mass of the replaced reaction mixture containing the heterogeneous hydrogenation catalyst accounts for 2-90% of the total volume or mass of the reaction mixture containing the heterogeneous hydrogenation catalyst, preferably 5-80%, and more preferably 10-40%.

[0053] In some implementations, the partial replacement in step 3) is performed at least once.

[0054] The homogeneous tungsten-containing catalyst can be one or more types, and can be added to the reactor partially or entirely before the reaction, or added continuously or intermittently during the reaction.

[0055] For heterogeneous hydrogenation catalysts, they can be separated from the reaction mixture during operation using an internal reactor separation device, with the catalyst remaining inside the reactor, or they can be separated using an external separation device and then returned to the reactor. The internal reactor separation device may include, but is not limited to, filtration equipment. In some embodiments, the pH of the reaction mixture obtained during continuous stable operation of the reactor (e.g., in step 1) or after completing steps 2) and 3) is 4-8 after removing the heterogeneous hydrogenation catalyst.

[0056] In some embodiments, the heterogeneous hydrogenation catalyst is activated. Suitable activation methods for heterogeneous hydrogenation catalysts are known in the art. In other embodiments, however, activation is not required, depending on the catalyst type.

[0057] In some implementations, the reaction can be carried out in a continuous or semi-continuous reactor, with stirring to ensure homogeneous mixing of the reactants. The reaction can also be carried out in a gas-liquid-solid three-phase sludge bed, fluidized bed, or fluidized bed reactor, which helps to improve mass transfer efficiency.

[0058] In some embodiments, the reaction temperature in the reactor is preferably controlled at ≥80°C, more preferably ≥100°C, and even more preferably ≥150°C, while ensuring that the reaction raw materials do not undergo thermal decomposition.

[0059] In some embodiments, the reaction pressure in the reactor can be set in the range of 1-15 MPa, preferably 6-14 MPa, and more preferably 10-13 MPa.

[0060] Hydrogen, as a reactant gas, can be introduced into the reactor in the form of pure hydrogen or as a mixture with other gases (such as CO, CO2, CH4, nitrogen, etc.).

[0061] In some implementations, a heterogeneous hydrogenation catalyst, along with at least a portion of the solvent, is added to the reactor, and when the reactor temperature and pressure reach target values, the carbohydrate source and / or polyol feed is initiated.

[0062] In some embodiments, the heterogeneous hydrogenation catalyst, along with at least a portion of the solvent, is added to the reactor. A solution feed containing the homogeneous tungsten-containing catalyst can be initiated before the carbohydrate source and / or polyols enter the reactor to promote the formation of highly active tungsten material (e.g., tungsten bronze), thereby shortening the time required for yield stabilization. In some embodiments, to accelerate the formation of highly active tungsten material (e.g., tungsten bronze), the solution feed containing the homogeneous tungsten-containing catalyst can be initiated at a temperature below the reaction temperature, or at the reaction temperature, or at a temperature above the reaction temperature.

[0063] The solvent of the solution containing the homogeneous tungsten catalyst may include, for example, water, at least one base compound, at least one alcohol compound, at least one hydrocarbon compound, at least one ether compound, at least one ketone compound, at least one acid compound, or a mixture of the above components. Preferably, it is a reaction mixture taken from the reactor after removing the heterogeneous hydrogenation catalyst.

[0064] In some embodiments, the heterogeneous hydrogenation catalyst, along with at least a portion of the solvent, is added to the reactor. A suitable solvent feed can be initiated before the carbohydrate source and / or polyols enter the reactor to hydrothermally treat the heterogeneous catalyst. The solvent may comprise, for example, water, at least one base compound, at least one alcohol compound, at least one hydrocarbon compound, at least one ether compound, at least one ketone compound, at least one acid compound, or a mixture of the foregoing. Preferably, any product from subsequent separation processes (e.g., including water and one or more C1-C6 alcohols) is used; more preferably, a reaction mixture removed from the reactor, from which the heterogeneous hydrogenation catalyst and the homogeneous tungsten-containing catalyst have been removed, is used.

[0065] After carbohydrate sources and / or polyols enter the reactor, the reaction temperature or higher can be used in the early stage of the reaction to promote the generation of organic acids from the raw materials in a short period of time, and react with the homogeneous tungsten-containing catalyst to generate highly active tungsten substances (such as tungsten bronze), thereby improving catalytic efficiency and shortening the time required for yield stabilization.

[0066] In some implementations, carbohydrate sources and / or polyols, homogeneous tungsten-containing catalysts (or mixtures thereof with one or more tungsten-free basic catalysts) and reaction gases may be fed together or separately into the reactor before entering the reactor.

[0067] The combined feed may be, for example, adding a carbohydrate source and / or polyols to the reactor after premixing them with a tungsten-containing homogeneous catalyst (or a mixture thereof with one or more tungsten-free basic catalysts), while the reaction gas is fed separately.

[0068] The combined feed may be, for example, a mixture of carbohydrate source and / or polyol with a tungsten-containing homogeneous catalyst (or a mixture thereof with one or more tungsten-free basic catalysts) before being added to the reactor along with the reactant gas.

[0069] The combined feed may be, for example, adding a carbohydrate source and / or polyols to the reactor after premixing with the reactant gas, or feeding a homogeneous tungsten-containing catalyst (or a mixture thereof with one or more tungsten-free basic catalysts) separately.

[0070] The combined feed may be, for example, a mixture of carbohydrate source and / or polyols premixed with the reactant gas, then mixed with a tungsten-containing homogeneous catalyst (or a mixture thereof with one or more tungsten-free basic catalysts), and added together to the reactor.

[0071] The combined feed may be, for example, a mixture of carbohydrate source and / or polyols, reactant gases, and a tungsten-containing homogeneous catalyst (or a mixture thereof with one or more tungsten-free basic catalysts) added to the reactor in a single step.

[0072] The separate feed can be, for example, introducing carbohydrate sources and / or polyols, reaction gases, tungsten-containing homogeneous catalysts (or mixtures thereof with one or more tungsten-free basic catalysts) independently into the reactor.

[0073] Before entering the reactor, the carbohydrate source and / or polyols, homogeneous tungsten-containing catalyst (or a mixture thereof with one or more tungsten-free basic catalysts), and at least a portion of the reactant gases may be selectively preheated or added directly to the reactor. The preheating may be performed before, during, or after premixing.

[0074] In some implementations, step 3 is initiated immediately after step 2) is completed.

[0075] In some implementations, step 3 is initiated after a certain period of time has elapsed since step 2).

[0076] The phrase "start step 3 after a period of time" means that step 3 can be started before the next step 2), or immediately after two or more steps 2), or before the last step 2) here.

[0077] In some embodiments, the replacement in step 3) refers to removing a portion of the reaction mixture containing the heterogeneous hydrogenation catalyst and replenishing it with a new mixture of the heterogeneous hydrogenation catalyst, wherein the replenished heterogeneous hydrogenation catalyst has the same dry basis mass as the removed heterogeneous hydrogenation catalyst.

[0078] The replenishment of the new heterogeneous hydrogenation catalyst mixture can be measured by mass or volume, a measurement method well known to those skilled in the art.

[0079] The solvent of the mixture of the new heterogeneous hydrogenation catalyst may include, for example, water, at least one base compound, at least one alcohol compound, at least one hydrocarbon compound, at least one ether compound, at least one ketone compound, at least one acid compound, or a mixture of the above components, and / or a reaction mixture removed from the reactor after removing the heterogeneous hydrogenation catalyst, and / or a reaction mixture removed from the reactor after removing the heterogeneous hydrogenation catalyst and the homogeneous tungsten-containing catalyst.

[0080] In this invention, after step 3), a regeneration and / or safe passivation process for the replaced heterogeneous hydrogenation catalyst may be included. The regeneration and recovery process may include introducing the removed portion of the reaction mixture containing the heterogeneous hydrogenation catalyst into a regeneration unit for treatment. The regenerated heterogeneous hydrogenation catalyst can be used alone during the replacement process or mixed with fresh heterogeneous catalyst. The safe passivation process may include nitrogen replacement and catalyst passivation, as well as catalyst recovery.

[0081] The regeneration and recycling process may include introducing the removed portion of the reaction mixture containing the heterogeneous hydrogenation catalyst into a regeneration unit. The regeneration unit may be treated with a washing liquid, etc. After treatment, a qualified heterogeneous hydrogenation catalyst can be obtained, which can be used alone in the replacement process or mixed with fresh heterogeneous catalyst.

[0082] The washing liquid may include one or more of the following: water, C1-C6 alcohols or polyols (including sugar alcohols) containing at least two hydroxyl groups, organic acids, tungsten-free organic bases, tungsten-free inorganic bases, and tungsten-free salts that are alkaline after dissolution.

[0083] The safety passivation process may include nitrogen purging. In some embodiments, the system is purged with nitrogen when the temperature drops to a suitable level, such as below 150°C (e.g., 90°C), ensuring that the nitrogen purity is above 99.9%.

[0084] The safe passivation process further includes catalyst passivation. In some embodiments, the oxidation rate and degree are controlled by adjusting the flow rate and total amount of air or oxygen introduced until the safe passivation of the catalyst is completed.

[0085] The safety passivation process may also include catalyst recovery. In some embodiments, when the temperature drops to a suitable level, such as below 100°C, the reaction mixture containing the heterogeneous hydrogenation catalyst is continuously fed to a dedicated filtration and drying unit for processing, ensuring that the catalyst complies with safety regulations during subsequent packaging and processing.

[0086] When both the regeneration and recycling process and the safety passivation process need to be carried out, this invention allows operation in the same or different equipment, selecting the best solution based on specific production needs to optimize resource use and reduce costs.

[0087] In some implementations, at least partially undissolved deposited tungsten may be present prior to passivation. During the passivation process of the heterogeneous catalyst, the deposited tungsten is oxidized and can be further removed using a washing solution after passivation.

[0088] In some implementation schemes, a safe passivation procedure for the heterogeneous hydrogenation catalyst will also be initiated when a complete replacement of the catalyst within the reactor is required.

[0089] In this invention, if it is necessary to shut down the production process, after step 2)a), the carbohydrate source and / or polyol stream and the homogeneous alkaline catalyst stream can be switched to the reaction mixture taken from the reactor, after removing the heterogeneous hydrogenation catalyst, and / or any stream (e.g., including water and one or more C1-C6 alcohols) in the subsequent separation process. Then, cooling and depressurization are started.

[0090] In some implementations, after the cooling and depressurization are completed, the reaction mixture containing the heterogeneous hydrogenation catalyst can be regenerated and / or safely passivated in the reactor, or it can be processed in a regeneration unit and then enter the safe passivation process.

[0091] When the production process needs to be paused for maintenance or catalyst replacement, the present invention also adopts an advantageous approach (e.g., through an intelligent switching procedure) that reduces the viscosity of the reaction mixture, facilitates the pumping of the reaction mixture, and simplifies the separation process of deposited tungsten from the catalyst.

[0092] In this invention, the tungsten-free alkaline catalyst can be periodically added to the reactor to replace the homogeneous tungsten-containing catalyst. The tungsten-free alkaline catalyst reacts online with the deposited tungsten in the reaction system to generate a new homogeneous tungsten-containing catalyst. When at least part of the deposited tungsten in the reaction system is converted into the homogeneous tungsten-containing catalyst, the online monitored parameter data (e.g., step 2)b)) reaches the set index value, the addition of the tungsten-free alkaline catalyst will be stopped, and the addition will switch back to the homogeneous tungsten-containing catalyst.

[0093] The parameters for online monitoring can be one or more combinations.

[0094] Here, the analytical instruments used for providing online monitoring of the reaction system fall within the general knowledge of technicians, and their selection depends on the specific process flow, equipment configuration, operating conditions, and the characteristics of the components in the feed, reaction zone, and chemical products. Examples of analytical instruments include online and / or remote analytical devices for analyzing the streams flowing out of the reaction zone, such as gas chromatographs, liquid chromatographs, infrared spectroscopy, ion chromatographs, pH meters, etc.

[0095] The inventors of this invention discovered that a large amount of high-viscosity polymer was adsorbed on the surface of the deposited tungsten formed during the reaction. However, when the addition of the homogeneous tungsten-containing catalyst was stopped and replaced with a tungsten-free alkaline catalyst, not only was the deposited tungsten in the reaction system successfully converted into a homogeneous tungsten-containing catalyst, but the high-viscosity polymer was also effectively removed from the reactor, and no high-viscosity polymer was found on the heterogeneous hydrogenation catalyst.

[0096] The method of the present invention achieves beneficial technical effects:

[0097] 1. The homogeneous tungsten-containing catalyst is replaced by a tungsten-free alkaline catalyst:

[0098] With a continuous feed of carbohydrate source and / or polyols and hydrogen, the activity of the homogeneous tungsten-containing catalyst decreases after a period of reaction. A tungsten-free alkaline catalyst is then added, and the tungsten-free alkaline catalyst reacts online with the deposited tungsten in the reaction system to generate a new homogeneous tungsten-containing catalyst online in the reactor. Once a certain amount of new homogeneous tungsten-containing catalyst has been generated, the addition of the tungsten-free alkaline catalyst is stopped, and the process is switched back to using the homogeneous tungsten-containing catalyst. This ensures the highly selective and continuous conversion of carbohydrate source and / or polyols to the target alcohol compounds in the presence of the homogeneous tungsten-containing catalyst.

[0099] For parameter monitoring and feed switching in the method of this invention, an online monitoring and automatic switching linkage program is preferably adopted: ensuring that carbohydrate sources and / or polyols and hydrogen are continuously fed throughout the entire process of replacing the homogeneous tungsten-containing catalyst, and that the reaction proceeds stably under the action of the tungsten-containing catalyst. This mechanism effectively avoids the situation where only a homogeneous basic catalyst is used due to delays or errors in human operation, thereby reducing fluctuations in the structure of main products and by-products, such as a decrease in the yield of ethylene glycol, an increase in the yield of 1,2-propanediol and 1,2-butanediol, and an increase in the yield of organic acids. In addition, this invention also improves the operational stability and product quality consistency of subsequent processes.

[0100] 2. Optionally, the heterogeneous hydrogenation catalyst is replaced with a new heterogeneous hydrogenation catalyst:

[0101] After the homogeneous tungsten-containing catalyst is replaced by a tungsten-free alkaline catalyst, the replacement of the heterogeneous hydrogenation catalyst with a new heterogeneous hydrogenation catalyst is initiated. A certain volume of the heterogeneous hydrogenation catalyst in the reactor is removed. Once the dry weight of the discharged heterogeneous hydrogenation catalyst reaches the target value, the system stops removing the reaction mixture and begins replenishing the mixture with a new heterogeneous hydrogenation catalyst. Replenishment is preferably stopped when the dry weight of the replenished heterogeneous hydrogenation catalyst is equal to that of the removed heterogeneous hydrogenation catalyst. This replacement of the heterogeneous hydrogenation catalyst can be carried out immediately after the homogeneous tungsten-containing catalyst is replaced by the tungsten-free alkaline catalyst or after a period of time following the replacement. This replacement enhances the catalytic activity of the heterogeneous hydrogenation catalyst. Throughout the replacement process, carbohydrate sources and / or polyols and hydrogen are continuously fed, ensuring the continuous production of the target alcohol compounds.

[0102] 3. Heterogeneous hydrogenation catalyst regeneration and / or safe passivation process:

[0103] The removed portion of the reaction mixture containing the heterogeneous hydrogenation catalyst can enter the regeneration unit, which can be treated, for example, with a washing solution. After treatment, a suitable heterogeneous hydrogenation catalyst can be obtained, which can be used alone during the replacement process or mixed with fresh heterogeneous catalyst.

[0104] The removed portion of the reaction mixture containing the heterogeneous hydrogenation catalyst can also undergo a safe passivation process. This can be achieved through nitrogen purging, catalyst passivation, filtration, and drying.

[0105] 4. Production shutdown procedure:

[0106] When the production process needs to be paused for maintenance or catalyst replacement, this invention, while the carbohydrate source and / or polyols and hydrogen continuously flow into the reaction system and are hydrogenated and cracked into the target alcohol compounds, switches the carbohydrate source and / or polyol stream and the homogeneous alkaline catalyst stream to a reaction mixture removed from the reactor, after the heterogeneous hydrogenation catalyst has been removed, and / or any stream from subsequent separation processes (e.g., including water and one or more C1-C6 alcohols). Subsequently, cooling and depressurization are initiated. This step not only reduces the viscosity of the reaction mixture, facilitating its pumping, but also simplifies the separation process for tungsten deposited in the catalyst. This production shutdown procedure is preferably performed using a smart switching procedure.

[0107] This invention achieves efficient, stable, and continuous production of carbohydrate sources and / or polyols into alcohols with equal and / or fewer carbon atoms, ensuring consistent product quality. It optimizes catalyst replacement and system maintenance procedures, improving efficiency and reducing catalyst loss. Specifically, deposited tungsten can be directly converted into a homogeneous catalyst dissolved in the reaction mixture without interrupting the reaction, eliminating the cumbersome separation and processing steps of traditional processes, greatly simplifying the process and improving production efficiency. Attached Figure Description

[0108] Figure 1 An embodiment of the continuous method according to the present invention is shown.

[0109] Figure 2 The graph shows the trend of the main product yield of Example 1 over time.

[0110] Figure 3 The graph shows a comparison of the main product yield trends over time in Example 1 and Comparative Examples 1-3 during the first 2000 hours.

[0111] Figure 4 The graph shows the trend of the main product yield of Example 2 over time.

[0112] Figure 5 The graph shows the trend of the main product yield of Example 3 over time.

[0113] Figure 6 The graph shows the trend of the main product yield of Example 4 over time.

[0114] Figure 7 The graph shows the trend of the main product yield of Example 5 over time.

[0115] The method of the present invention is achieved by Figure 1 To illustrate, the specific selection of the control system hardware is known to those skilled in the art.

[0116] exist Figure 1 In the attached diagram, the numbers are three digits. The first digit from the left is the type code, where 1 represents logistics and 2 represents equipment. The last two digits are the sequence number.

[0117] exist Figure 1 In this process, a target alcohol compound is produced in a continuous stirred tank reactor 201, in which a heterogeneous hydrogenation catalyst has been pre-added. Under specific temperature and pressure conditions, a carbohydrate source and / or polyol stream 104, a homogeneous tungsten-containing catalyst solution stream 103, and a hydrogen stream 105 are continuously supplied to the reactor 201. Within the reactor, a stirrer 203 thoroughly mixes the feedstock, thereby converting it into the target alcohol compound. During the reaction, the reaction mixture continuously flows out through a filter 202 via stream 106, while the heterogeneous hydrogenation catalyst is retained within the reactor by the filter 202.

[0118] 1. Replacement of the homogeneous catalyst with a tungsten-free alkaline catalyst:

[0119] When the system detects that the homogeneous tungsten-containing catalyst needs to be replaced by a tungsten-free alkaline catalyst, it automatically switches to alkaline catalyst solution stream 102 to replace the homogeneous tungsten-containing catalyst solution stream 103 in the continuous stirred tank reactor 201 without changing the liquid and gas feed rates, until the target value is reached. Then, it automatically switches back to use homogeneous tungsten-containing catalyst solution stream 103 to replace the tungsten-free alkaline catalyst solution stream 102. Throughout the process, carbohydrate sources and / or polyols and hydrogen are continuously fed to ensure the continuous production of alcohol compounds.

[0120] 2. Optionally, the heterogeneous catalyst is replaced with a new heterogeneous hydrogenation catalyst:

[0121] Once the homogeneous tungsten-containing catalyst in step 1 above has been replaced by a tungsten-free alkaline catalyst and the target value has been reached, immediately or after a certain period of time, the discharge of the reaction mixture in reactor 201 is initiated, allowing it to be discharged to regeneration unit 204 via stream 107 until the discharged dry basis mass reaches the set value, at which point the discharge automatically stops. New heterogeneous hydrogenation catalyst mixture is then added to reactor 201 via stream 101 until the system detects that the added dry basis mass has reached the set value, at which point the addition stops. Throughout the entire process, the raw materials are continuously fed to ensure the continuous production of alcohol compounds.

[0122] 3. Heterogeneous hydrogenation catalyst regeneration and / or safe passivation process:

[0123] Regeneration and recycling process: The heterogeneous hydrogenation catalyst in the regeneration unit 204 can be washed with washing liquid. After treatment, a heterogeneous hydrogenation catalyst that meets the requirements can be obtained. It can be used alone in the replacement process or mixed with fresh heterogeneous catalyst. It can be recycled back to the continuous stirred tank reactor 201 through material 108.

[0124] Safe passivation process: The heterogeneous hydrogenation catalyst can also be safely passivated within the regeneration unit 204, or via stream 109 into the safe passivation process. The safe passivation process may include, for example, nitrogen purging and catalyst passivation. It then proceeds to a filtration and drying section to ensure the catalyst complies with safety regulations during subsequent packaging and processing. This safe passivation and recovery process is well known in the art.

[0125] 4. Production shutdown process

[0126] When it is determined that the production process of alcohol compounds needs to be stopped for maintenance, catalyst replacement, etc., without changing the liquid or gas feed rate, the feed stream is replaced with the reaction mixture removed from the reactor after removing the heterogeneous hydrogenation catalyst and / or any stream from the subsequent separation process, and a cooling and depressurization procedure is initiated. Detailed Implementation

[0127] Example

[0128] The technical solution of the present invention will be further described below with reference to embodiments. The embodiments of the present invention should not be construed as limiting the present invention.

[0129] Example 1:

[0130] The continuous reaction was conducted in a 10-liter continuously stirred reactor equipped with a filter, pre-loaded with 1000 grams of a heterogeneous hydrogenation catalyst. This heterogeneous hydrogenation catalyst was a framework-type nickel-based composite alloy catalyst (Ni3Sn:Ni3Mo = 97:3 by weight; for example, this composite alloy catalyst was prepared by melting Ni3Sn alloy and Ni3Mo alloy together with aluminum; the preparation method can also be found in Example 1 of patent application CN202510268388.1). Other feeds were: hydrogen at a flow rate of 936 standard liters (NL) / hour, 65% glucose aqueous solution at a flow rate of 1.70 kg / hour, and 8% sodium tungstate aqueous solution at a flow rate of 0.15 kg / hour. The volume corresponding to the liquid level in the reactor was 7 liters. During the continuous reaction, the reaction temperature was 255°C and the reaction pressure was 12 MPa. In the continuous reaction process, the heterogeneous hydrogenation catalyst is retained in the reactor by a filter, while the liquid product stream flows continuously through the filter into the liquid-phase condenser and the liquid-phase gas-liquid separator. The gas product stream continuously enters the gas-phase condenser and the gas-phase gas-liquid separator from the top pipe of the reactor. The liquids from the bottom of the gas-liquid separators from the gas and liquid phases are collected and mixed separately, and the composition of the mixture is analyzed. This mixture is defined as the reaction liquid.

[0131] After 24 hours of operation, the composition of the reaction solution was as follows: 2.8% by weight of monohydric alcohol, including 1.4% by weight of methanol, 1.3% by weight of ethanol, and 0.1% by weight of isopropanol; 52.1% by weight of dihydric alcohol, including 47.5% by weight of ethylene glycol, 3.5% by weight of propylene glycol, and 1.1% by weight of butanediol; 1.6% by weight of polyhydric alcohol (containing at least three hydroxyl groups), including 0.4% by weight of sorbitol, 0.6% by weight of butylenetetroxide, and 0.6% by weight of glycerol; 0.2% by weight of monobasic acid; and 0.6% by weight of sodium tungstate.

[0132] 1. Periodic replacement of homogeneous catalysts with tungsten-free basic catalysts:

[0133] At 1000 hours of operation, a 65% (w / w) glucose aqueous solution and hydrogen were continuously fed. Without changing the feed rates of the liquid and gas, the sodium tungstate aqueous solution was periodically switched to a 5% (w / w) sodium hydroxide aqueous solution until the pH of the reaction mixture rose to 0.7 as detected online. At this point, the system automatically switched back to the sodium tungstate aqueous solution. This operation was repeated periodically every 1000 hours.

[0134] 2. Heterogeneous hydrogenation catalysts are periodically replaced by new heterogeneous hydrogenation catalysts:

[0135] At 3000 hours of operation, a 65 wt% glucose aqueous solution and hydrogen were continuously fed. Without changing the liquid and gas feed rates, the sodium tungstate aqueous solution was switched to a 5 wt% sodium hydroxide aqueous solution until the pH of the reaction mixture rose to 0.7 as detected online. At this point, the system automatically switched back to sodium tungstate aqueous solution, and then 20% of the total volume of the reaction mixture in the reactor was discharged. Afterward, an equal volume of the new heterogeneous hydrogenation catalyst mixture with the same initial concentration was added to the reactor via a pump. This process was repeated periodically every 1000 hours, achieving periodic replacement of the heterogeneous catalyst and effectively ensuring the stability of product yield and the activity of the heterogeneous hydrogenation catalyst. At 5908 hours of operation, the reaction was actively stopped.

[0136] Here, to actively stop the reaction operation, the homogeneous catalyst is replaced with a tungsten-free alkaline catalyst. For the safe passivation and handling of heterogeneous hydrogenation catalysts and the production shutdown procedures, please refer to the appendix. Figure 1 And the preceding description.

[0137] Typical product yields (based on HPLC analysis) are shown in Figure 2 middle.

[0138] Comparative Example 1:

[0139] The experiment was conducted according to Example 1, except that the homogeneous tungsten-containing catalyst was not periodically replaced by a tungsten-free alkaline catalyst, nor was the heterogeneous hydrogenation catalyst periodically replaced by a new heterogeneous hydrogenation catalyst.

[0140] The method was run continuously for 1218 hours before being stopped due to a significant decrease in the yield of ethylene glycol.

[0141] Comparative Example 2:

[0142] The experiment was conducted according to Example 1, except that the homogeneous tungsten-containing catalyst was not periodically replaced by a tungsten-free alkaline catalyst, nor was the heterogeneous hydrogenation catalyst periodically replaced by a new heterogeneous hydrogenation catalyst. Instead, an aqueous sodium hydroxide solution (0.52% by weight) was added to the feed.

[0143] The specific feed flow rates are as follows: 1.70 kg / h for 65% glucose aqueous solution, and 0.15 kg / h for 8% sodium tungstate aqueous solution and 0.52% sodium hydroxide aqueous solution.

[0144] The method was run continuously for 1290 hours before being stopped due to a significant decrease in the yield of ethylene glycol.

[0145] Comparative Example 3:

[0146] The experiment was conducted according to Example 1, except that the homogeneous tungsten-containing catalyst was not periodically replaced by a tungsten-free alkaline catalyst, nor was the heterogeneous hydrogenation catalyst periodically replaced by a new heterogeneous hydrogenation catalyst. Instead, an aqueous sodium hydroxide solution (2.60% by weight) was added to the feed.

[0147] The specific feed flow rates are as follows: 1.70 kg / h for 65% glucose aqueous solution, and 0.15 kg / h for 8% sodium tungstate aqueous solution and 2.60% sodium hydroxide aqueous solution.

[0148] The method was run continuously for 498 hours, but the ethylene glycol yield remained lower than that of other implementation schemes, so the reaction was stopped.

[0149] Typical product yields (based on HPLC analysis) and tungsten deposition amounts (based on IC analysis) for Example 1 and Comparative Examples 1-3 are shown in Table 1. A comparison of typical product yields (based on HPLC analysis) for Example 1 and Comparative Examples 1-3 in the first 2000 hours is shown in Table 1. Figure 3 middle.

[0150]

[0151] Tungsten deposition amount (grams) = Total mass of tungsten in the feed sodium tungstate - Total mass of tungsten in the discharge reaction mixture

[0152] Table 1

[0153]

[0154] a: Sugar concentration in reactor = Dry sugar mass in feed sugar solution / (Mass of feed sugar solution + Mass of feed sodium tungstate solution and / or Mass of feed sodium hydroxide solution);

[0155] b: Sodium hydroxide concentration in reactor = Dry basis mass of sodium hydroxide in feed sodium hydroxide aqueous solution / (Mass of feed sugar aqueous solution + Mass of feed sodium tungstate aqueous solution and / or Mass of feed sodium hydroxide aqueous solution);

[0156] c: Sodium tungstate concentration in reactor = dry basis mass of sodium tungstate in feed sodium tungstate aqueous solution / (mass of feed sugar aqueous solution + mass of feed sodium tungstate aqueous solution and / or mass of feed sodium hydroxide aqueous solution).

[0157] As can be seen, in Comparative Example 2, with a glucose concentration of 60 wt% and a sodium hydroxide content of 0.04 wt%, tungsten deposition was only slightly inhibited. In Comparative Example 3, the sodium hydroxide content was increased to 0.21 wt%, but this resulted in a significant decrease in the total yield of ethylene glycol and propylene glycol. In Example 1, the amount of tungsten deposition was significantly reduced, while the product yield remained stable at a high level for a longer period.

[0158] Example 2:

[0159] The continuous reaction was conducted in a 10-liter continuously stirred reactor equipped with a filter, pre-loaded with 1000 grams of a heterogeneous hydrogenation catalyst. This heterogeneous hydrogenation catalyst was a framework-type nickel-based composite alloy catalyst (Ni3Sn:Ni3Mo = 97:3 (weight ratio), for example, prepared by melting Ni3Sn alloy and Ni3Mo alloy together with aluminum; the preparation method can also be found in Example 1 of patent application CN202510268388.1). Other feeds were: hydrogen feed rate of 936 NL / h, 50 wt% sucrose aqueous solution feed rate of 2.21 kg / h, and 4 wt% sodium tungstate aqueous solution feed rate of 0.25 kg / h. The volume corresponding to the liquid level in the reactor was 7 liters. During the continuous reaction, the reaction temperature was 253°C and the reaction pressure was 12 MPa. In the continuous reaction process, the heterogeneous hydrogenation catalyst is retained in the reactor by a filter, while the liquid product stream flows continuously through the filter into the liquid-phase condenser and the liquid-phase gas-liquid separator. The gas product stream continuously enters the gas-phase condenser and the gas-phase gas-liquid separator from the top pipe of the reactor. The liquids from the bottom of the gas-liquid separators from the gas and liquid phases are collected and mixed separately, and the composition of the mixture is analyzed. This mixture is defined as the reaction liquid.

[0160] At the 300-hour mark, a 50% wt% sucrose aqueous solution and hydrogen were continuously fed. Without changing the feed rates of the liquid and gas, the sodium tungstate aqueous solution was periodically switched to a 2% wt% sodium hydroxide aqueous solution until the concentration of ethylene glycol in the reaction mixture changed to 20% of its original concentration as detected online. At this point, the system automatically switched the sodium hydroxide aqueous solution back to the sodium tungstate aqueous solution. This process was repeated periodically every 500 hours.

[0161] This method was run continuously for 1529 hours with stable yields before the reaction was actively stopped. Typical product yields (based on HPLC analysis) are shown below. Figure 4 middle.

[0162] Example 3:

[0163] The continuous reaction was carried out in a 10-liter continuously stirred reactor equipped with a filter, pre-loaded with 1000 grams of heterogeneous hydrogenation catalyst, which was a framework-type nickel-based composite alloy catalyst (Ni3Sn:Ni3Mo = 97:3 (weight ratio), for example, prepared by melting Ni3Sn alloy and Ni3Mo alloy together with aluminum; the preparation method can also be found in Example 1 of patent application CN202510268388.1). The volume corresponding to the liquid level in the reactor was 7 liters. During the heating and pressurization process, the hydrogen feed flow rate was 56.2 standard liters (NL) / hour, the feed flow rate of 50% ethylene glycol aqueous solution was 0.102 kg / hour, and the feed flow rate of 9% sodium tungstate aqueous solution was 0.005 kg / hour. When the reaction temperature reached 253℃ and the reaction pressure reached 12MPa, the feed flow rate of 50% wt% ethylene glycol aqueous solution was adjusted to 1.02 kg / h, and the feed flow rate of 9% wt% sodium tungstate aqueous solution was adjusted to 0.05 kg / h. After continuous feeding for 24 hours, without changing the liquid and gas feed rates, the 50% wt% ethylene glycol aqueous solution was replaced with 65% wt% glucose aqueous solution, and the hydrogen feed flow rate was adjusted to 562 standard liters (NL) / h. The temperature was decreased by 1℃ every 100 hours until the reaction temperature reached 250℃ and stabilized. During the continuous reaction, the heterogeneous hydrogenation catalyst was retained in the reactor by the filter, while the liquid product stream continuously flowed through the filter into the liquid phase condenser and liquid phase gas-liquid separator, and the gas product stream continuously entered the gas phase condenser and gas phase gas-liquid separator from the top pipe of the reactor. The liquids from the bottom of the gas-liquid separator from the gas and liquid phases were collected and mixed separately, and the composition of the mixture was analyzed. This mixture was defined as the reaction liquid.

[0164] 1. Periodic replacement of homogeneous catalysts with tungsten-free basic catalysts:

[0165] At 1300 hours of operation, a 65 wt% glucose aqueous solution and hydrogen were continuously fed. Without changing the feed rates of the liquid and gas, the sodium tungstate aqueous solution was switched to a 9 wt% sodium hydroxide aqueous solution until the pH of the reaction mixture rose to 0.8 as detected online. At this point, the system automatically switched the sodium hydroxide aqueous solution back to the sodium tungstate aqueous solution. This operation was repeated periodically every 1300 hours.

[0166] 2. Heterogeneous hydrogenation catalysts are periodically replaced by new heterogeneous hydrogenation catalysts:

[0167] At 2600 hours of operation, a 65 wt% glucose aqueous solution and hydrogen were continuously fed. Without changing the feed rates of the liquid and gas, the sodium tungstate aqueous solution was switched to a 9 wt% sodium hydroxide aqueous solution until the pH of the reaction mixture was detected to rise to 0.8 online. At this point, the system automatically switched the sodium hydroxide aqueous solution back to the sodium tungstate aqueous solution. Then, 20% of the total volume of the reaction mixture in the reactor was discharged. After that, an equal volume of the new heterogeneous hydrogenation catalyst mixture with the same initial concentration was added to the reactor via a pump.

[0168] After 3197 hours of operation, the yield remained stable, and the reaction was actively stopped. Typical product yields (based on HPLC analysis) are shown below. Figure 5 middle.

[0169] Example 4:

[0170] The continuous reaction was carried out in a 10-liter continuously stirred reactor equipped with a filter, pre-loaded with 1000 grams of heterogeneous hydrogenation catalyst, which was a framework-type nickel-based composite alloy catalyst (Ni3Sn:Ni3Mo = 97:3 (weight ratio), for example, prepared by melting Ni3Sn alloy and Ni3Mo alloy together with aluminum; the preparation method can also be found in Example 1 of patent application CN202510268388.1). The volume corresponding to the liquid level in the reactor was 7 liters. During the heating and pressurization process, the hydrogen feed rate was 93.6 standard liters (NL) / hour, the water feed rate was 0.170 kg / hour, and the 5 wt% sodium tungstate aqueous solution feed rate was 0.015 kg / hour. When the reaction temperature reached 255°C and the reaction pressure reached 12 MPa, the water feed rate was adjusted to 1.70 kg / hour, and the 5 wt% sodium tungstate aqueous solution feed rate was adjusted to 0.15 kg / hour. After 16 hours of continuous feeding, without changing the liquid and gas feed rates, the water was replaced with a 65% aqueous solution of glucose and xylose (glucose:xylose = 80:20 (wt / wt)), and the hydrogen feed flow rate was adjusted to 936 standard liters (NL) / hour. After 200 hours of operation, the reaction temperature was lowered to 253°C for stable operation. During the continuous reaction, the heterogeneous hydrogenation catalyst was retained in the reactor by a filter, while the liquid product stream continuously flowed through the filter into the liquid-phase condenser and liquid-phase gas-liquid separator. The gas product stream continuously entered the gas-phase condenser and gas-phase gas-liquid separator from the top pipe of the reactor. The liquids from the bottom of the gas-liquid separators were collected and mixed separately, and the composition of the mixture was analyzed; this mixture was defined as the reaction liquid.

[0171] At 700 hours of operation, a 65% glucose and xylose aqueous solution and hydrogen were continuously fed. Without changing the feed rates of the liquid and gas, the sodium tungstate aqueous solution was periodically switched to a 5% (w / w) sodium hydroxide aqueous solution until the concentration of ethylene glycol in the reaction mixture changed to 8% of its original concentration as detected online. At this point, the system automatically switched the sodium hydroxide aqueous solution back to the sodium tungstate aqueous solution. This operation was repeated periodically after 700 hours.

[0172] This method was run continuously for 2020 hours, with the homogeneous catalyst replaced twice by a tungsten-free alkaline catalyst, maintaining a stable yield until the reaction was actively stopped. Typical product yields (based on HPLC analysis) are shown below. Figure 6 middle.

[0173] Example 5:

[0174] The continuous reaction was carried out in a 10-liter continuously stirred reactor equipped with a filter, pre-loaded with 1000 grams of a heterogeneous hydrogenation catalyst, which was a framework-type nickel-based composite alloy catalyst (Ni3Sn:Ni3Mo = 97:3 (weight ratio), for example, prepared by melting Ni3Sn alloy and Ni3Mo alloy together with aluminum; the preparation method can also be found in Example 1 of patent application CN202510268388.1). The volume corresponding to the liquid level in the reactor was 7 liters. During the heating and pressurization process, the hydrogen feed flow rate was 93.6 standard liters (NL) / hour, and the reaction liquid described in Example 1 was added to the reactor at feed flow rates of 0.170 kg / hour and 0.015 kg / hour, respectively. When the reaction temperature reached 260°C and the reaction pressure reached 12 MPa, the feed flow rate of the reaction liquid was adjusted to 1.70 kg / hour and 0.15 kg / hour until steady-state operation was achieved. Without changing the liquid and gas feed rates, the feed was switched to: a 65 wt% glucose and xylose mixed aqueous solution (glucose:xylose = 80:20 (wt / wt)) at a flow rate of 1.70 kg / h, a 5 wt% sodium tungstate aqueous solution at a flow rate of 0.15 kg / h, and a hydrogen feed rate adjusted to 936 standard liters (NL) / h. After 24 hours, the temperature was lowered to 253°C, and stable operation was achieved. During the continuous reaction, the heterogeneous hydrogenation catalyst was retained in the reactor by a filter, while the liquid product stream continuously flowed through the filter into the liquid phase condenser and liquid phase gas-liquid separator, and the gas product stream continuously entered the gas phase condenser and gas phase gas-liquid separator from the top pipe of the reactor. The liquids from the bottom of the gas-liquid separators from the gas and liquid phases were collected and mixed separately, and the composition of the mixture was analyzed. This mixture was defined as the reaction liquid.

[0175] At 900 hours of operation, a 65 wt% aqueous solution of glucose and xylose and hydrogen were continuously fed. Without changing the feed rates of the liquid and gas, the sodium tungstate aqueous solution was periodically switched to a 5 wt% sodium hydroxide aqueous solution until the online detection showed a decreasing trend in the tungsten atom concentration in the reaction mixture. When the decrease reached 50 wt% of the maximum tungsten atom concentration in the reaction mixture when the homogeneous catalyst was replaced by a tungsten-free alkaline catalyst, the system automatically switched the sodium hydroxide aqueous solution back to the sodium tungstate aqueous solution. This operation was repeated periodically after 700 hours.

[0176] This method was run continuously for 2011 hours, with the homogeneous catalyst replaced twice by a tungsten-free alkaline catalyst, maintaining a stable yield until the reaction was actively stopped. Typical product yields (based on HPLC analysis) are shown below. Figure 7 middle.

[0177] Any implementation described herein may be freely combined with one or more other implementations described herein, and the resulting technical solutions or ideas shall be regarded as part of the original disclosure or original record of the present invention, and shall not be regarded as new content not disclosed or anticipated herein, unless those skilled in the art consider the combination to be obviously unreasonable.

Claims

1. A continuous method for converting carbohydrate sources and / or polyols into alcohols with the same and / or fewer carbon numbers, comprising the following steps: 1) To continuously react one or more carbohydrate sources and / or polyols in a reactor in the presence of hydrogen, a heterogeneous hydrogenation catalyst and a homogeneous tungsten-containing catalyst to obtain a reaction mixture containing alcohols with equal and / or fewer carbon numbers; 2) a) During continuous stable operation, when the reaction time reaches at least 50 hours, the addition of the homogeneous tungsten-containing catalyst shall be stopped, and the addition of a tungsten-free alkaline catalyst shall begin, and / or During continuous stable operation, when the pH of the reaction mixture decreases by at least 0.1 and / or the concentration change of certain products in the reaction mixture is at least 0.5% of their original concentration and / or the tungsten deposition is at least 1% by weight of the catalyst, the addition of the homogeneous tungsten-containing catalyst shall be stopped, and the addition of a tungsten-free alkaline catalyst shall begin. When selecting the conditions for "stopping the addition of the homogeneous tungsten-containing catalyst", the first condition that occurs shall prevail. b) After adding the tungsten-free alkaline catalyst for at least 1 hour and / or the pH of the reaction mixture obtained in a) rises by at least 0.1 and / or the concentration of some products changes again by at least 3% of their original concentration and / or at least 10% of the deposited tungsten is converted to homogeneous tungsten-containing catalyst and / or when the tungsten atom concentration in the reaction mixture shows a decreasing trend, and the decrease is at least 1% by weight of the maximum tungsten atom concentration in the reaction mixture in step a), stop adding the tungsten-free alkaline catalyst and add the homogeneous tungsten-containing catalyst again. When selecting the conditions for "stopping the addition of tungsten-free alkaline catalyst", the first condition that occurs shall prevail. 3) Optionally, the heterogeneous catalyst in the reaction mixture obtained in step 2) is partially replaced with a new heterogeneous catalyst.

2. The method of claim 1, comprising at least one of the following features: In step 1), the homogeneous tungsten-containing catalyst is in the form of a mixture of a homogeneous tungsten-containing catalyst and one or more tungsten-free basic catalysts; In steps 2) and 3), carbohydrate sources and / or polyols and hydrogen are continuously fed; The concentration of the carbohydrate source and / or polyols in the total liquid feed is 10-90% by weight, preferably 30-80% by weight, wherein the weight of the carbohydrate source and / or polyols is based on a dry basis. Preferably, the pH of the total liquid feed containing the carbohydrate source and / or polyols is 3-9. Carbohydrate sources and / or polyols are introduced into the reactor along with at least a portion of the solvent; Carbohydrate sources and / or polyols are partially or completely dissolved in a solvent. Preferred solvents include aqueous media, organic media containing alkylene glycols, water, C1-C6 alcohols or polyols containing at least two hydroxyl groups (including sugar alcohols), organic acids, ethers and other suitable organic compounds, or mixtures thereof. Such solvents are capable of effectively dissolving a variety of carbohydrate sources and / or polyols. Carbohydrate sources and / or polyols are added to the reactor in slurry form, such as aqueous mixtures of water and hemicellulose, sugars, glucose, and / or starch; and The alcohols with equal and / or fewer carbon numbers refer to diols and / or monools and / or polyols containing at least three hydroxyl groups.

3. The method according to claim 1 or 2, comprising at least one of the following features: The heterogeneous hydrogenation catalyst can be used in conjunction with a heterogeneous tungsten-containing catalyst; The heterogeneous hydrogenation catalyst is a supported catalyst or an unsupported catalyst, preferably comprising one or more metals from groups 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, and 15 of the periodic table, such as magnesium, boron, aluminum, germanium, tin, antimony, selenium, lanthanum, cerium, samarium, titanium, zirconium, vanadium, niobium, chromium, molybdenum, tungsten, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, zinc, etc., or combinations thereof. These metals may exist in their metallic form, alloy form, hydride form, oxide form, or other compound form. The heterogeneous hydrogenation catalyst is stored in a suitable solvent, which includes, for example, water, at least one base compound, at least one alcohol compound, at least one hydrocarbon compound, at least one ether compound, at least one ketone compound, at least one acid compound, or a mixture of the above components, and / or a reaction mixture removed from the reactor to remove the heterogeneous hydrogenation catalyst, and / or a reaction mixture removed from the reactor to remove the heterogeneous hydrogenation catalyst and the homogeneous tungsten-containing catalyst. Preferably, the pH of the storage system for the heterogeneous hydrogenation catalyst is 4-12, more preferably 5-10, and more preferably 5-9. The concentration of the heterogeneous hydrogenation catalyst in the reactor is at least 50 g / L, preferably at least 110 g / L, more preferably at least 130 g / L, wherein the catalyst weight is based on a dry basis and the volume is based on the volume of the liquid medium in the reactor. The processing capacity per kilogram of heterogeneous hydrogenation catalyst is at least 0.3 kg, preferably at least 0.4 kg, more preferably at least 0.5 kg of carbohydrate source and / or polyol, wherein the weight of the catalyst is based on dry-based catalyst, and the weight of the carbohydrate source and / or polyol is based on dry-based carbohydrate source and / or polyol. The reactor has a processing capacity of at least 50 kg, preferably at least 60 kg, and more preferably at least 80 kg per hour of carbohydrate source and / or polyol, wherein the volume is based on the volume of the liquid medium in the reactor and the weight of the carbohydrate source and / or polyol is based on dry basis. The heterogeneous tungsten-containing catalyst and the homogeneous tungsten-containing catalyst can each independently include, but are not limited to, tungsten compounds, complexes, or elemental forms, and can be used alone or in combination. Examples include tungsten carbides, nitrides, phosphides, oxides, sulfides, chlorides, hydroxides, tungsten bronze, tungstic acid and polytungstic acid, tungstates, metatungstic acid, metatungstates, paratungstic acid, paratungstates, peroxytungstic acid, peroxytungstates, tungsten heteropolyacids, etc. Preferably, tungsten oxides, tungsten bronze, tungstic acid and polytungstic acid, sodium tungstate, and dissolved tungstate ions, metatungstate ions, and paratungstate ions are used. The homogeneous tungsten-containing catalyst refers to a tungsten-containing catalyst that can be dissolved in a solvent to form a homogeneous form. Preferred solvents include aqueous media, organic media containing alkylene glycols, water, C1-C6 alcohols or polyols (including sugar alcohols) containing at least two hydroxyl groups, organic acids, ethers and other suitable organic compounds, or mixtures thereof. The weight ratio of the tungsten-containing catalyst (based on tungsten atoms) to the carbohydrate source and / or polyols is >0-10, preferably 0.0002-9, more preferably 0.0003-8, wherein the weight of the carbohydrate source and / or polyols is based on dry basis. The tungsten-free alkaline catalyst may include one or more organic bases, inorganic bases, and salts that are alkaline after dissolution, such as one or more selected from ammonium hydroxide, alkali metal or alkaline earth metal hydroxides, alkali metal and alkaline earth metal salts of carbonic acid or carboxylic acid, alkali metal and alkaline earth metal salts of phosphoric acid, zinc salts of zinc carbonate and carboxylic acid, and / or one or more selected from organic bases such as amine compounds and alkali metal salts of alcohols, more preferably sodium hydroxide, sodium carbonate, sodium bicarbonate, or combinations thereof; and The tungsten-free alkaline catalyst is used in a solvent, either partially or completely dissolved. Preferably, the tungsten-free alkaline catalyst is used in the form of a homogeneous alkaline catalyst. Preferred solvents include aqueous media, organic media containing alkylene glycols, water, C1-C6 alcohols or polyols (including sugar alcohols) containing at least two hydroxyl groups, organic acids, ethers and other suitable organic compounds, or mixtures thereof.

4. The method according to any one of claims 1-3, comprising at least one of the following features: In steps 2)a) and b), one or more of the conditions can be detected; Step 2) Perform this step at least once, preferably at least twice; In step 2), "certain products" refers to compounds that can be detected and thereby monitored in the reaction process, such as C1-C6 alcohols and / or organic acids. C1-C6 alcohols may include methanol, ethanol, ethylene glycol, propylene glycol, butanediol, glycerol, butanetetraethanolamine, sorbitol, etc., and organic acids may include formic acid, acetic acid, lactic acid, glycolic acid, glyceric acid, etc. In step 2)a), the reaction time reaches at least 100 hours; In step 2)a), the pH of the reaction mixture decreases by at least 0.2, more preferably by at least 0.3; In step 2)a), the concentration change of certain products in the reaction mixture is at least 0.7% of their original concentration, more preferably at least 0.9% of their original concentration; In step 2)a), the amount of tungsten deposited is at least 5% by weight of the catalyst, more preferably at least 7% by weight, and even more preferably at least 9% by weight; In step 2)b), the addition of the tungsten-free alkaline catalyst is stopped after at least 1.2 hours, preferably at least 1.5 hours; In step 2)b), the addition of a tungsten-free alkaline catalyst is stopped when the pH of the reaction mixture rises by at least 0.2, more preferably at least 0.4, and even more preferably at least 0.

6. In step 2)b), the addition of the tungsten-free alkaline catalyst is stopped when the concentration of certain products changes by at least 5% of their original concentration, more preferably at least 7% of their original concentration. In step 2)b), when at least 12%, more preferably at least 15%, of the deposited tungsten is converted into a homogeneous tungsten-containing catalyst, the addition of a tungsten-free alkaline catalyst is stopped. In step 2)b), when the concentration of tungsten atoms in the reaction mixture shows a decreasing trend, and the decrease is at least 5% by weight of the maximum concentration of tungsten atoms in the reaction mixture in step a), more preferably at least 10% by weight of the maximum concentration of tungsten atoms in the reaction mixture in step a), the addition of tungsten-free alkaline catalyst is stopped. In step 3), the reaction mixture containing the heterogeneous hydrogenation catalyst is replaced by a new heterogeneous catalyst mixture, wherein the volume or mass of the replaced reaction mixture containing the heterogeneous hydrogenation catalyst accounts for 2-90% of the total volume or mass of the reaction mixture containing the heterogeneous hydrogenation catalyst, preferably 5-80%, more preferably 10-40%. and The partial replacement in step 3) shall be performed at least once.

5. The method according to any one of claims 1-4, comprising at least one of the following features: The homogeneous tungsten-containing catalyst can be one or more types, and can be added to the reactor partially or entirely before the reaction, or can be added continuously or intermittently during the reaction. For heterogeneous hydrogenation catalysts, they can be separated from the reaction mixture by an internal separation device during operation, with the catalyst remaining inside the reactor, or they can be separated by an external separation device and then returned to the reactor. During continuous stable operation of the reactor (e.g., in step 1) or after completing steps 2) and 3), the pH of the reaction mixture effluent from the reactor after removal of the heterogeneous hydrogenation catalyst is 4-8; and The reaction is carried out in a continuous or semi-continuous reactor and is stirred to ensure uniform mixing of the reactants.

6. The method according to any one of claims 1-5, comprising at least one of the following features: The reaction temperature in the reactor is controlled at ≥80℃, more preferably ≥100℃, and even more preferably ≥150℃; The reaction pressure in the reactor can be set in the range of 1-15 MPa, preferably 6-14 MPa, and more preferably 10-13 MPa; and Hydrogen, as a reactant gas, can be introduced into the reactor in the form of pure hydrogen or as a mixture with other gases (such as CO, CO2, CH4, nitrogen, etc.).

7. The method according to any one of claims 1-6, wherein step 1) comprises at least one of the following features: A heterogeneous hydrogenation catalyst, along with at least a portion of the solvent, is added to the reactor. When the reactor temperature and pressure reach the target values, the carbohydrate source and / or polyol feed is initiated. A heterogeneous hydrogenation catalyst, together with at least a portion of the solvent, is added to the reactor. Before the carbohydrate source and / or polyols enter the reactor, a solution feed containing the homogeneous tungsten-containing catalyst is initiated. The initiation of the solution feed containing the homogeneous tungsten-containing catalyst can be carried out at a temperature below the reaction temperature, or at the reaction temperature, or at a temperature above the reaction temperature. The solvent of the solution containing the homogeneous tungsten catalyst may include, for example, water, at least one base compound, at least one alcohol compound, at least one hydrocarbon compound, at least one ether compound, at least one ketone compound, at least one acid compound, or a mixture of the above components. Preferably, it is a reaction mixture taken from the reactor after removing the heterogeneous hydrogenation catalyst. The heterogeneous hydrogenation catalyst, along with at least a portion of the solvent, is added to the reactor. Before the carbohydrate source and / or polyols enter the reactor, a suitable solvent feed is initiated to hydrothermally treat the heterogeneous catalyst. This solvent may contain, for example, water, at least one base compound, at least one alcohol compound, at least one hydrocarbon compound, at least one ether compound, at least one ketone compound, at least one acid compound, or a mixture of the above components. Preferably, any product from subsequent separation processes (e.g., including one or more of water and C1-C6 alcohols) is used. More preferably, a reaction mixture removed from the reactor, after the heterogeneous hydrogenation catalyst and the homogeneous tungsten-containing catalyst have been removed, is used. After the carbohydrate source and / or polyols are introduced into the reactor, the initial reaction temperature or a temperature higher than the reaction temperature can be used.

8. The method according to any one of claims 1-7, wherein the feeding form in step 1) comprises at least one of the following features: Before entering the reactor, carbohydrate sources and / or polyols, homogeneous tungsten-containing catalysts (or mixtures thereof with one or more tungsten-free basic catalysts) and reaction gases can be fed together or separately into the reactor; The combined feed consists of adding a carbohydrate source and / or polyols to the reactor after premixing them with a tungsten-containing homogeneous catalyst (or a mixture thereof with one or more tungsten-free basic catalysts), while the reaction gas is fed separately. The combined feed consists of premixing a carbohydrate source and / or polyols with a tungsten-containing homogeneous catalyst (or a mixture thereof with one or more tungsten-free basic catalysts), then mixing it with the reaction gas and adding it together to the reactor. The combined feed consists of adding a carbohydrate source and / or polyols to the reactor after premixing with the reactant gas, and feeding a homogeneous tungsten-containing catalyst (or a mixture thereof with one or more tungsten-free alkaline catalysts) separately. The combined feed consists of premixing carbohydrate sources and / or polyols with the reaction gas, then mixing them with a tungsten-containing homogeneous catalyst (or a mixture thereof with one or more tungsten-free alkaline catalysts), and adding them together to the reactor. The combined feed consists of a carbohydrate source and / or polyols, a reaction gas, and a tungsten-containing homogeneous catalyst (or a mixture thereof with one or more tungsten-free alkaline catalysts) added to the reactor in a single batch. The separate feed refers to the independent introduction of carbohydrate sources and / or polyols, reaction gases, and tungsten-containing homogeneous catalysts (or mixtures thereof with one or more tungsten-free basic catalysts) into the reactor; and Before entering the reactor, the carbohydrate source and / or polyols, homogeneous tungsten-containing catalyst (or a mixture thereof with one or more tungsten-free basic catalysts), and at least a portion of the reaction gas may be selectively preheated or added directly to the reactor, wherein the preheating may be performed before, during, or after premixing.

9. The method according to any one of claims 1-8, comprising at least one of the following features: After step 2) is completed, immediately start step 3); After a period of time has elapsed since step 2), step 3) is started. The phrase "after a period of time" means that step 3) can be started before the next step 2), or immediately after two or more steps 2) or before the last step 2) here. Step 3) replacement refers to removing a portion of the reaction mixture containing the heterogeneous hydrogenation catalyst and replenishing it with a new mixture containing the heterogeneous hydrogenation catalyst, wherein the replenished heterogeneous hydrogenation catalyst has the same dry basis mass as the removed heterogeneous hydrogenation catalyst; and The solvent of the mixture of the new heterogeneous hydrogenation catalyst may include, for example, water, at least one base compound, at least one alcohol compound, at least one hydrocarbon compound, at least one ether compound, at least one ketone compound, at least one acid compound, or a mixture of the above components, and / or a reaction mixture removed from the reactor after removing the heterogeneous hydrogenation catalyst, and / or a reaction mixture removed from the reactor after removing the heterogeneous hydrogenation catalyst and the homogeneous tungsten-containing catalyst.

10. The method according to any one of claims 1-9, comprising at least one of the following features: After step 3), the process includes the regeneration and / or safe passivation of the replaced heterogeneous hydrogenation catalyst. The regeneration and recovery process may include introducing the removed portion of the reaction mixture containing the heterogeneous hydrogenation catalyst into a regeneration unit for treatment. The regenerated heterogeneous hydrogenation catalyst can be used alone during the replacement process or mixed with fresh heterogeneous catalyst. The safe passivation process may include nitrogen replacement and catalyst passivation, as well as catalyst recovery. The washing liquid includes one or more of the following: water, C1-C6 alcohol or polyols (including sugar alcohols) containing at least two hydroxyl groups, organic acids, tungsten-free organic bases, tungsten-free inorganic bases, and tungsten-free salts that are alkaline after dissolution. By adjusting the flow rate and total amount of air or oxygen introduced, the oxidation rate and degree are controlled until the safe passivation of the catalyst is completed. There may be at least some undissolved deposited tungsten before passivation. During the passivation process of heterogeneous catalysts, the deposited tungsten will be oxidized and can be further removed by washing solution after passivation. When shutting down the production process, after step 2)a), the carbohydrate source and / or polyol stream and the homogeneous basic catalyst stream are switched to a reaction mixture removed from the reactor, after the heterogeneous hydrogenation catalyst has been removed, and / or any stream from subsequent separation processes (e.g., including water and one or more C1-C6 alcohols). Then, cooling and depressurization are initiated; and After the cooling and depressurization are completed, the reaction mixture containing the heterogeneous hydrogenation catalyst can be regenerated and / or safely passivated in the reactor, or it can be processed in the regeneration unit and then enter the safe passivation process.

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