CN110724037B - Process for preparing benzenediol - Google Patents
Process for preparing benzenediol Download PDFInfo
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- CN110724037B CN110724037B CN201810783013.9A CN201810783013A CN110724037B CN 110724037 B CN110724037 B CN 110724037B CN 201810783013 A CN201810783013 A CN 201810783013A CN 110724037 B CN110724037 B CN 110724037B
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C37/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring
- C07C37/60—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring by oxidation reactions introducing directly hydroxy groups on a =CH-group belonging to a six-membered aromatic ring with the aid of other oxidants than molecular oxygen or their mixtures with molecular oxygen
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J29/00—Catalysts comprising molecular sieves
- B01J29/89—Silicates, aluminosilicates or borosilicates of titanium, zirconium or hafnium
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2229/00—Aspects of molecular sieve catalysts not covered by B01J29/00
- B01J2229/10—After treatment, characterised by the effect to be obtained
- B01J2229/18—After treatment, characterised by the effect to be obtained to introduce other elements into or onto the molecular sieve itself
- B01J2229/186—After treatment, characterised by the effect to be obtained to introduce other elements into or onto the molecular sieve itself not in framework positions
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts
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Abstract
The invention relates to the field of benzenediol, and discloses a method for preparing benzenediol, which comprises the following steps: phenol, at least one oxidant, and a catalyst are contacted in a reaction zone of a moving bed reactor under oxidation reaction conditions. The method can effectively avoid the possible temperature runaway and other problems of the catalyst bed layer of the fixed bed reactor, can obtain high phenol conversion rate, effective utilization rate of the oxidant and selectivity of the hydroquinone, and can prolong the service life of the catalyst; meanwhile, the catalyst with the activity which cannot meet the requirement can be removed from the reaction zone for regeneration under the condition that the device does not stop.
Description
Technical Field
The invention relates to the field of benzenediol, in particular to a method for preparing benzenediol.
Background
Hydroquinone and catechol are two important chemical raw materials and chemical intermediates, and have wide application. Catechol is useful as a rubber hardener, a plating additive, a skin antiseptic, a hair dye, a photographic developer, a color antioxidant, a fur dye developer, a paint and a varnish anti-skinning agent. Hydroquinone is mainly used as developer, anthraquinone dye, azo dye, synthetic ammonia cosolvent, rubber antioxidant, polymerization inhibitor, stabilizer for paint and essence, and antioxidant.
In the prior art, benzoquinones are formed primarily by oxidizing an aromatic hydroxy compound (e.g., phenol) with oxygen or an oxygen-containing gas, a copper-containing catalyst, and optionally a promoter, followed by a reduction reaction to form hydroquinone, but this process does not produce both benzoquinones and benzenediols.
In the beginning of the eighties of the last century, taramasso, italy, in USP4410501, discloses a novel catalytic oxidation material called titanium silicalite molecular sieve (TS-1), which has a very good selective oxidation effect on hydrocarbons, alcohols, phenols, etc.
The titanium silicalite molecular sieve is used as a catalyst to catalyze and oxidize phenol to obtain hydroquinone and catechol simultaneously. However, there is still room for improvement in the conversion of phenol by this production method, and the problem of temperature runaway is likely to occur when the conventional method is carried out in a fixed bed reactor.
Disclosure of Invention
The invention aims to solve the problems that the conversion rate of phenol is to be further improved and temperature runaway is easy to occur in the prior art, and provides a method for preparing benzenediol. The method for preparing the hydroquinone has higher phenol conversion rate, effective utilization rate of the oxidant and selectivity of the hydroquinone.
The inventor of the invention finds that when phenol is oxidized by using a catalyst in a fixed bed reactor to directly prepare the benzenediol, the problem that the local temperature in a catalyst bed is overhigh and the temperature runaway is easy to occur in the reaction process, and the shutdown is needed when the catalyst is regenerated after being inactivated, so that the working efficiency is low.
In order to overcome the above-mentioned disadvantages in the preparation of hydroquinone from phenol by an oxidation process, the present invention provides a method for preparing hydroquinone, comprising: phenol, at least one oxidant, and a catalyst are contacted in a reaction zone of a moving bed reactor under oxidation reaction conditions.
Preferably, the process further comprises feeding at least one acid to the reaction zone in an amount such that the pH of the liquid mixture in contact with the catalyst is in the range of from 3 to 5.5.
Preferably, the catalyst contains a vanadium titanium silicalite molecular sieve.
The method can effectively avoid the problems of temperature runaway of a catalyst bed layer and the like possibly occurring in a fixed bed reactor, can obtain high phenol conversion rate, effective utilization rate of an oxidant and hydroquinone selectivity, and can prolong the service life of the catalyst; meanwhile, the catalyst with the activity which cannot meet the requirement can be removed from the reaction zone for regeneration under the condition that the device does not stop.
Detailed Description
The following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.
The invention provides a method for preparing benzenediol, which comprises the following steps: phenol, at least one oxidant, and a catalyst are contacted in a reaction zone of a moving bed reactor under oxidation reaction conditions.
According to one embodiment of the invention, the catalyst moves in the reaction zone in the axial direction of the reactor.
According to the method of the present invention, during the contacting, the catalyst moves in the reaction zone along the axial direction of the reactor (i.e., the reaction zone), which can effectively avoid the problem that local temperature in the catalyst bed is too high during the reaction when the catalyst bed is fixed in the reactor. In the present invention, the "reaction zone" refers to a zone for bringing phenol into contact with an oxidizing agent and a catalyst to perform an oxidation reaction.
The catalyst may be fed from the upper part (typically the top) of the reaction zone and the oxidant and phenol may be fed from the lower or upper part of the reaction zone respectively to react with the oxidant and phenol in contact therewith as the catalyst falls. Preferably, the catalyst and the oxidizing agent are fed into the reaction zone from the upper part of the reaction zone, and the phenol is fed into the reaction zone from the lower part (generally the bottom) of the reaction zone, and during the movement, the phenol and the oxidizing agent form a mixture and react in contact with the catalyst. The specific feed locations for the catalyst, oxidant and phenol may be selected according to the specific specifications of the reactor.
According to the process of the present invention, the catalyst may be moved out of the reaction zone after the reaction, and the catalyst moved out of the reaction zone may be recycled into the reaction zone. When the activity of the catalyst moving out of the reaction zone cannot meet the use requirement, the titanium silicalite molecular sieve moving out of the reaction zone can be regenerated and then fed into the reaction zone again. The regeneration conditions of the present invention are not particularly limited, and can be carried out by a method conventionally used in the art, for example: solvent soaking and/or high temperature roasting. The regeneration may be carried out in a regenerator outside the reactor; or a regeneration zone can be arranged in the reactor, and the titanium silicalite molecular sieve moving out of the reaction zone is sent into the regeneration zone for regeneration and then sent into the reaction zone again.
When the catalyst moved out of the reaction zone is sent into a regeneration zone or a regenerator for regeneration, the catalyst with the activity meeting the requirement can be correspondingly fed into the reaction zone in a supplementing way. The amount of the replenished catalyst may be selected according to the activity of the replenished catalyst so as to allow the reaction in the reaction zone to proceed smoothly.
According to the process of the present invention, the moving speeds of the catalyst, phenol and oxidizing agent in the reaction zone can be appropriately selected depending on the treatment capacity of the reaction zone. Generally, the feed rate of phenol may be from 5 to 100mL/min, preferably from 10 to 80mL/min, more preferably from 20 to 60mL/min. The moving speeds of the catalyst and the oxidizing agent in the reaction zone may be appropriately selected according to the ratio between phenol and the catalyst and the oxidizing agent, which will be described later.
According to a preferred embodiment of the invention, the catalyst comprises a vanadium titanium silicalite. In order to further improve the activity, selectivity and stability of the catalyst, preferably, the vanadium-titanium-silicon molecular sieve comprises: vanadium, titanium, silicon and oxygen, wherein the molecular sieve satisfies X 1-1.8 /X 0.4-0.9 ＝C，0.2<C<1，X 0.4-0.9 The ratio of the pore diameter of the micropores of the molecular sieve in the range of 0.4-0.9nm to the distribution quantity of the total pore diameter, X 1-1.8 Is the proportion of the pore diameter of the micropores of the molecular sieve in the range of 1-1.8nm in the distribution quantity of the pore diameter of the total micropores. The inventor finds that the vanadium-titanium-silicon molecular sieve with a special physicochemical characteristic structure is used for phenol oxidation reaction in a moving bed reactor, so that the selectivity of modulating a target product (hydroquinone) is facilitated, and the conversion rate of phenol and the effective utilization rate of an oxidant are improved. Even more preferably, 0.25<C<0.85。
The preferred vanadium-titanium-silicon molecular sieve of the invention has pore diameter distribution within the range of 0.4-0.9nm and also has distribution within the range of 1-1.8nm, the ratio of the proportion of the pore diameter of micropores within the range of 1-1.8nm to the total pore diameter distribution of micropores within the range of 0.4-0.9nm is C, and 0.2<C<1, preferably, 0.25<C<0.85, further preferably 0.3<C<0.8. In the present invention, the pore size of the micropores can be measured by a conventional method, and the method of the present invention has no particular requirement and is well known to those skilled in the art, for example, by using N 2 Static adsorption and the like.
It is to be noted here that, if the ratio of the pore size distribution of micropores to the total pore size distribution of micropores is in the range of 1 to 1.8nm, the ratio is<At 1%, the pore distribution of the micropores is negligible, i.e. no micropore distribution in the range of 1-1.8nm is considered, as known to the person skilled in the art. Thus, the invention is described in N 2 The pore diameter of the micropores in the range of 1-1.8nm in the static adsorption test refers to the proportion of the pore diameter distribution of the micropores in the range of 1-1.8nm to the total pore diameter distribution>1 percent. The microporous molecular sieve prepared by conventional direct hydrothermal synthesis has the ratio of the micropore size distribution to the total micropore size distribution in the range of 1-1.8nm<1 percent of microporous molecular sieve which is treated and modified by a common treatment and modification method and has a lower proportion of the distribution of the pore diameters of the micropores in the range of 1-1.8nm in the distribution of the pore diameters of the total micropores, namely<10%, typically<1％。
According to the invention, preferably, the molecular sieve satisfies nV/nTi = a, I 960 /I 800 = B, B = i (a + 1) nTi, where 0.1<A<10，0.2<B<1，0<I, nV is the molar weight of vanadium element in the molecular sieve, nTi is the molar weight of titanium element in the molecular sieve, I 960 The infrared absorption spectrum of the molecular sieve is 960cm -1 Absorption intensity in the vicinity, I 800 The infrared absorption spectrum of the molecular sieve is 800cm -1 Absorption intensity in the vicinity, preferably, 0.2<A<5，0.3<B<0.8. Therefore, the method is more favorable for the diffusion of reactant and product molecules in the catalytic oxidation reaction, not only can further improve the effective utilization rate of the oxidant, but also can further improve the effective utilization rate of the oxidantCan more effectively modulate the selectivity of the target product.
According to the invention, it is preferred that the molecular sieve satisfies T w /T k ＝D，0.2<D<0.5, further preferably 0.25<D<0.45, wherein, T w Is the micropore volume of the molecular sieve, T k Is the total pore volume of the molecular sieve.
According to the invention, preferably, the silicon element: titanium element: the molar ratio of the vanadium element is 100: (0.1-10): (0.01-5), more preferably silicon element: titanium element: the molar ratio of the vanadium element is 100: (0.2-5): (0.2-2.5), and further preferably silicon element: titanium element: the molar ratio of vanadium elements is 100: (0.5-4): (0.5-2), more preferably 100: (1-4): (0.5-2).
According to the invention, preferably, the surface silicon-titanium ratio of the molecular sieve is not lower than the bulk silicon-titanium ratio, wherein the silicon-titanium ratio refers to the molar ratio of silicon oxide to titanium oxide; further preferably, the ratio of the surface silicon-titanium ratio to the bulk silicon-titanium ratio is 1.2 or more; more preferably, the ratio of the surface silicon-titanium ratio to the bulk silicon-titanium ratio is 1.2-5; still more preferably, the ratio of the surface silicon to titanium ratio to the bulk silicon to titanium ratio is 1.5 to 4.5. The surface silicon-titanium ratio is measured by adopting an X-ray photoelectron spectroscopy, and the bulk silicon-titanium ratio is measured by adopting an X-ray fluorescence spectroscopy.
The vanadium-titanium-silicon molecular sieve has the advantages of micropore size distribution in the range of 1-1.8nm, and preferably, the surface silicon-titanium ratio is not lower than the bulk silicon-titanium ratio. The invention has no special requirements on the preparation method of the vanadium-titanium-silicon molecular sieve, as long as the vanadium-titanium-silicon molecular sieve with the structure can be prepared. Preferably, the preparation method of the vanadium-titanium-silicon molecular sieve comprises the following steps:
(1) Mixing a catalyst containing a titanium silicalite molecular sieve with an acid solution, carrying out first heat treatment on the obtained mixture, and separating to obtain a first solid;
(2) And mixing the first solid, the vanadium source, the alkali source and the water, and then carrying out second heat treatment.
According to the invention, the catalyst containing the titanium silicalite molecular sieve can contain fresh titanium silicalite molecular sieve and can also contain a titanium silicalite molecular sieve discharging agent. However, from the viewpoint of cost control, etc., it is preferable that the catalyst containing the titanium silicalite molecular sieve is a titanium silicalite discharging agent in order to save cost.
The titanium silicalite discharging agent may be discharged from various apparatuses using a titanium silicalite as a catalyst, for example, from an oxidation reaction apparatus using a titanium silicalite as a catalyst. The oxidation reaction may be various oxidation reactions, for example, the discharging agent of the reaction apparatus using the titanium-silicon molecular sieve as the catalyst may be one or more of a discharging agent of an ammoximation reaction apparatus, a discharging agent of a hydroxylation reaction apparatus, and a discharging agent of an epoxidation reaction apparatus, specifically, one or more of a discharging agent of a cyclohexanone ammoximation reaction apparatus, a discharging agent of a phenol hydroxylation reaction apparatus, and a discharging agent of an epoxidation reaction apparatus, and preferably, the discharging agent is a catalyst that is deactivated in a basic environment, and therefore, for the present invention, it is preferable that the discharging agent of the titanium-silicon molecular sieve is a discharging agent of a cyclohexanone ammoximation reaction apparatus (such as deactivated titanium-silicon molecular sieve TS-1, powdery, and having a particle size of 100 to 500 nm).
In the present invention, the discharging agent is a deactivated catalyst whose activity cannot be restored to 50% of the initial activity by a conventional regeneration method such as solvent washing or calcination (the initial activity is the average activity of the catalyst within 1 hour under the same reaction conditions; for example, in the actual cyclohexanone oximation reaction, the initial activity of the catalyst is generally 95% or more).
The activity of the discharging agent varies depending on its source. Generally, the activity of the discharging agent can be 5-95% of the activity of the titanium silicalite when fresh (i.e., the activity of the fresh agent). Preferably, the activity of the discharging agent can be less than 50% of the activity of the titanium silicalite molecular sieve in a fresh state, and further preferably, the activity of the discharging agent can be 10-40% of the activity of the titanium silicalite molecular sieve in a fresh state. The activity of the titanium-silicon molecular sieve fresh agent is generally more than 90%, and usually more than 95%.
In the present invention, the discharging agent may be derived from an industrial deactivator or a deactivated catalyst after reaction in a laboratory.
In the invention, the discharging agent of each device is respectively measured by adopting the reaction of each device, and the discharging agent is the discharging agent provided that the activity of the discharging agent is lower than that of a fresh catalyst in the same device under the same reaction condition. As mentioned before, the activity of the discharging agent is preferably less than 50% of the activity of the fresh catalyst.
In the present invention, taking the discharging agent of the cyclohexanone ammoximation reaction device as an example, the activity is measured by the following method:
the TS-1 molecular sieve (prepared as described in "Zeolites,1992, vol.12 2 2.1%) was placed in a 100mL slurry bed reactor with continuous feed and membrane separation means, and a mixture of water and 30wt% hydrogen peroxide (water to hydrogen peroxide volume ratio of 10: 9) A mixture of cyclohexanone and tert-butanol was added at a rate of 10.5mL/h (the volume ratio of cyclohexanone to tert-butanol was 1:2.5 Adding 36wt% ammonia water at a speed of 5.7mL/h, simultaneously adding the three material flows, continuously discharging at corresponding speed, maintaining the reaction temperature at 80 ℃, sampling the product after the reaction is stable, analyzing the composition of the liquid phase by using a gas chromatography method every 1 hour, calculating the conversion rate of cyclohexanone by using the following formula, and using the conversion rate as the activity of the titanium silicalite molecular sieve. Conversion of cyclohexanone = [ (molar amount of cyclohexanone added-not) molar amount of cyclohexanone reacted)/molar amount of cyclohexanone added]X 100%. Wherein the result of 1h is taken as the initial activity.
According to the present invention, the heat treatment is generally carried out under autogenous pressure in the case of sealing, unless otherwise specified.
According to a preferred embodiment of the present invention, the temperature of the first heat treatment is preferably 40 to 200 ℃, more preferably 50 to 180 ℃, and still more preferably 60 to 180 ℃.
According to the present invention, the time of the first heat treatment can be determined as required, and for the present invention, the time of the first heat treatment is preferably 0.5 to 360 hours, preferably 1 to 240 hours, and more preferably 2 to 120 hours.
According to the present invention, the temperature of the second heat treatment is preferably 100 to 200 ℃, more preferably 120 to 180 ℃, and still more preferably 140 to 170 ℃.
According to the invention, the time of the second heat treatment can be determined according to requirements, and for the invention, the time of the second heat treatment is 0.5-96h, preferably 2-48h, and more preferably 6-24h.
According to the invention, it is preferred that the method of the invention further comprises: the catalyst containing the titanium silicalite molecular sieve is roasted before being mixed with the acid solution. Preferred conditions for the firing for the present invention include: the roasting temperature is 300-800 ℃, preferably 550-600 ℃; the roasting time is 2-12h, preferably 2-4h, and the roasting atmosphere comprises air atmosphere.
According to the invention, the concentration of the acid solution is preferably >0.1mol/L, more preferably ≧ 1mol/L, further preferably 1-15mol/L. In the invention, the main solvent of the acid solution is water, and other solvent auxiliaries can be added according to the requirement. The vanadium-titanium-silicon molecular sieve prepared in the way has more obvious characteristics such as pore volume, micropore distribution of 1-1.8nm and the like.
According to the invention, catalysts containing titanium silicalite are preferred: a vanadium source: acid: alkali source: the mass ratio of water is 100: (0.1-10): (0.005-50): (0.5-50): (20-1000), more preferably 100: (0.5-2.0): (1-15): (1-20): (100-800) using SiO as catalyst containing titanium-silicon molecular sieve 2 Measured as H, acid + The alkali source is N or OH - More preferably, the mass ratio of the catalyst containing the titanium silicalite molecular sieve to the acid is 100: (2-15).
In the present invention, the titanium silicalite molecular sieve can be common titanium silicalite molecular sieves with various topological structures, and preferably, the titanium silicalite molecular sieve is selected from a titanium silicalite molecular sieve with an MFI structure, a titanium silicalite molecular sieve with an MEL structure, and a titanium silicalite molecular sieve with a BEA structure. More preferably, the titanium silicalite molecular sieve is a titanium silicalite molecular sieve of MFI structure, such as TS-1 molecular sieve.
According to the invention, the acid can be selected from a wide range of types, and can be an organic acid and/or an inorganic acid, preferably an inorganic acid; wherein, the inorganic acid can be one or more of HCl, sulfuric acid, perchloric acid, nitric acid and phosphoric acid, and is preferably phosphoric acid; the organic acid can be C1-C10 organic carboxylic acid, preferably one or more of formic acid, acetic acid, propionic acid, naphthenic acid peroxyacetic acid and peroxypropionic acid.
According to the method of the present invention, the variety of the alkali source is wide, and the alkali source can be an organic alkali source and/or an inorganic alkali source, wherein the inorganic alkali source can be ammonia, or alkali whose cation is alkali metal or alkaline earth metal, such as sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, potassium carbonate, barium hydroxide, etc., and the organic alkali source can be one or more of urea, aliphatic amine compound, aliphatic alcohol amine compound, and quaternary ammonium base compound.
In the invention, the quaternary ammonium base can be various organic quaternary ammonium bases, and the aliphatic amine can be various NH 3 In which at least one hydrogen is substituted with an aliphatic hydrocarbon group (preferably an alkyl group), which may be a variety of NH 3 Wherein at least one hydrogen is substituted with a hydroxyl-containing aliphatic hydrocarbon group (preferably an alkyl group).
Specifically, the quaternary ammonium base may be a quaternary ammonium base represented by formula II, the aliphatic amine may be an aliphatic amine represented by formula III, and the aliphatic alcohol amine may be an aliphatic alcohol amine represented by formula IV:
in the formula II, R 5 、R 6 、R 7 And R 8 Each is C 1 -C 4 Alkyl of (2) including C 1 -C 4 Straight chain alkyl of (2) and C 3 -C 4 Branched alkyl groups of (a), for example: r 5 、R 6 、R 7 And R 8 Each may be methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl or tert-butyl.
R 9 (NH 2 ) n (formula III)
In the formula III, n is an integer of 1 or 2. When n is 1, R 9 Is C 1 ～C 6 Alkyl of (2) including C 1 ～C 6 Straight chain alkyl of (2) and C 3 -C 6 Such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, isopentyl, tert-pentyl and n-hexyl. When n is 2, R 9 Is C 1 -C 6 Alkylene of (2) including C 1 ～C 6 Linear alkylene of (A) and (C) 3 ～C 6 Such as methylene, ethylene, n-propylene, n-butylene, n-pentylene or n-hexylene. More preferably, the aliphatic amine compound is one or more of ethylamine, n-butylamine, butanediamine and hexamethylenediamine
(HOR 10 ) m NH (3-m) (formula IV)
In the formula IV, m are R 10 Are the same or different and are each C 1 -C 4 Alkylene of (2) including C 1 -C 4 Linear alkylene of (A) and (C) 3 -C 4 Branched alkylene groups of (2) such as methylene, ethylene, n-propylene and n-butylene; m is 1, 2 or 3. More preferably, the aliphatic alcohol amine compound is one or more of monoethanolamine, diethanolamine and triethanolamine.
According to a preferred embodiment of the present invention, in order to further improve the pore order of the synthesized vanadium-titanium-silicon molecular sieve, the alkali source is preferably one or more of sodium hydroxide, ammonia water, ethylenediamine, n-butylamine, butanediamine, hexamethylenediamine, monoethanolamine, diethanolamine, triethanolamine, tetraethylammonium hydroxide and tetrapropylammonium hydroxide.
Wherein, when the alkali source contains ammonia water, the mol ratio of the alkali source includes NH in molecular form 3 And NH in ionic form 4 + The presence of ammonia.
According to the process of the present invention, preferably the alkali source is provided in the form of an alkali solution, more preferably an alkali solution having a pH >9.
According to a preferred embodiment of the present invention, the vanadium source is preferably an oxide of vanadium, a halide of vanadium, vanadic acid (HVO) 3 ) Orthovanadic acid (H) 3 VO 4 ) Pyrovanadic acid (H) 4 V 2 O 7 、H 3 V 3 O 9 ) Vanadate (corresponding salt of the aforementioned vanadate), carbonate of vanadium, nitrate of vanadium, sulfate of vanadium, phosphate of vanadium, and hydroxide of vanadium. Including but not limited to sodium vanadate, ammonium metavanadate, vanadium pentoxide, vanadium oxytrichloride, potassium metavanadate, vanadyl sulfate, vanadium acetylacetonate, vanadium tetrachloride, and the like.
The advantages of the invention are illustrated by the use of vanadium tetrachloride, vanadium phosphate salts as examples in the examples of the invention.
In a more preferred embodiment of the invention, the process of mixing the catalyst containing the titanium silicalite molecular sieve with the acid solution with the molar concentration of more than 0.1mol/L is carried out under the condition of refluxing the acid solution, and the titanium silicalite molecular sieve obtained under the condition has more obvious characteristic physicochemical characteristics.
According to the present invention, it is preferred that the method of the present invention further comprises a step of recovering a product from the heat-treated material of step (2), the step of recovering the product being a conventional method familiar to those skilled in the art, and it is not particularly required herein to refer to a process of filtering, washing, drying and calcining the product. Wherein, the drying process can be carried out at the temperature of between room temperature and 200 ℃, and the roasting process can be carried out at the temperature of between 300 and 800 ℃ in a nitrogen atmosphere for 0.5 to 6 hours and then in an air atmosphere for 3 to 12 hours.
According to a preferred embodiment of the invention, a titanium source is also added during the second heat treatment.
The titanium source may be selected conventionally in the art according to the process of the present invention, and for the purposes of the present invention it is preferred that the titanium source is selected from inorganic titanium salts and/or organic titanates.
In the present invention, the inorganic titanium salt is selected from various hydrolyzable titanium salts, and may be selected from TiX, for example 4 、TiOX 2 Or Ti (SO) 4 ) 2 Etc. in various formsA titanium-containing salt of formula (I), wherein X is halogen, preferably chlorine, wherein preferably the inorganic titanium salt is selected from TiCl 4 、Ti(SO 4 ) 2 And TiOCl 2 One or more of (a).
In the present invention, the organic titanate is preferably represented by the structural formula M 4 TiO 4 Wherein M is preferably an alkyl group having 1 to 4 carbon atoms, and 4M's may be the same or different, preferably the organotitanate is selected from one or more of isopropyl titanate, n-propyl titanate, tetrabutyl titanate and tetraethyl titanate.
Titanium sulfate, tetrabutyl titanate, are used as examples in the specific embodiments of the present invention, but do not limit the scope of the present invention accordingly.
When a titanium source is added during the second heat treatment, it is preferable that the step (2) is performed as follows: and mixing a vanadium source, an alkali source and water to obtain a mixture, and mixing the mixture, a titanium source and the first solid to perform the second heat treatment.
According to the method of the invention, the mass ratio of the catalyst containing the titanium silicalite molecular sieve to the titanium source can be 100: (0.1-10), preferably 100: (0.2-5) catalyst containing titanium silicalite molecular sieve is SiO 2 The titanium source is calculated as TiO 2 And (6) counting. By adopting the preferred embodiment, the surface silicon-titanium ratio of the obtained molecular sieve material is not lower than that of bulk silicon-titanium ratio, and in addition, the obtained molecular sieve material has more micropore size distribution in the range of 1-1.8nm, and is particularly favorable for phenol oxidation reaction.
According to the method of the present invention, the catalyst may be used in an amount of a catalyst capable of performing a catalytic function. Specifically, the mass ratio of phenol to catalyst may be from 0.1 to 50:1, preferably 1 to 50:1, such as 10-20:1.
the oxidizing agent may be any of a variety of materials commonly used in the art that are capable of oxidizing phenol to form benzenediols. The method is particularly suitable for the occasion of oxidizing phenol by taking peroxide as an oxidizing agent so as to prepare the benzenediol, so that the effective utilization rate of the peroxide can be obviously improved, and the production cost of the benzenediol can be reduced. The peroxide is a compound containing an-O-O-bond in the molecular structure, and can be selected from hydrogen peroxide, hydroperoxide and peracid. The hydroperoxide is a substance obtained by substituting one hydrogen atom in a hydrogen peroxide molecule with an organic group. The peracid refers to an organic oxyacid having an-O-O-bond in the molecular structure. Specific examples of the peroxide may include, but are not limited to: hydrogen peroxide, tert-butyl hydroperoxide, cumene peroxide, cyclohexyl hydroperoxide, peracetic acid and propionic acid. Preferably, the oxidizing agent is hydrogen peroxide, which further reduces the separation cost. The hydrogen peroxide may be hydrogen peroxide in various forms commonly used in the art.
From the viewpoint of further improving the safety of the method of the present invention, it is preferable to use hydrogen peroxide in the form of an aqueous solution. According to the process of the invention, when the hydrogen peroxide is provided in the form of an aqueous solution, the concentration of the aqueous hydrogen peroxide solution may be a concentration conventional in the art, for example: 20-80 wt%. Aqueous solutions of hydrogen peroxide at concentrations meeting the above requirements may be prepared by conventional methods or may be obtained commercially, for example: can be 30 percent by weight of hydrogen peroxide, 50 percent by weight of hydrogen peroxide or 70 percent by weight of hydrogen peroxide which can be obtained commercially.
According to the process of the present invention, preferably, the molar ratio of phenol to oxidant is 1: (0.1-10), more preferably 1: (0.2-5), more preferably 1: (1-4).
According to the process of the present invention, preferably, said contacting is carried out in the presence of at least one solvent. Generally, the solvent may be selected from at least one of water, C1-C6 alcohols, C3-C8 ketones, C2-C8 nitriles, and C2-C8 carboxylic acids. Specific examples of the solvent may include, but are not limited to: water, methanol, ethanol, acetic acid, n-propanol, isopropanol, tert-butanol, isobutanol, acetone, butanone and acetonitrile. Preferably, the solvent is acetic acid, acetone, methanol and water, more preferably methanol and/or water. By adopting the preferred embodiment, the mixing degree of reactants in a reaction system is more favorably improved, the diffusion is strengthened, the intensity of the reaction is more conveniently adjusted, and particularly, the selectivity of the target product hydroquinone is well adjusted and controlled.
Generally, the mass ratio of solvent to phenol may be (1-100): 1, preferably (1-25): 1, e.g. (7-20): 1.
according to the process of the present invention, the solvent may be fed into the reaction zone by various methods commonly used in the art such that contacting the phenol and the oxidant with the catalyst, preferably a vanadium titanium silicalite, is carried out in the presence of the solvent. For example: the solvent may be fed into the reaction zone from the upper part thereof, may be fed into the reaction zone from the lower part thereof, and may be fed into the reaction zone from the middle part thereof. When the solvent is fed into the reaction zone from the upper portion thereof, the solvent is preferably fed into the reaction zone at the same position as the oxidizing agent, and more preferably the solvent and the oxidizing agent are fed into the reaction zone through the same feed port.
The process according to the invention preferably further comprises feeding at least one acid to the reaction zone in an amount such that the pH of the liquid mixture in contact with the titanium silicalite molecular sieves is preferably in the range of from 3 to 5.5, preferably in the range of from 4 to 5.5. Thus, the selectivity of hydroquinone can be obviously improved, and higher phenol conversion rate and effective utilization rate of an oxidant can be obtained; and, compared with no acid addition, under the same conditions, even at lower temperature, high phenol conversion rate, oxidant effective utilization rate and hydroquinone selectivity can be obtained. The pH of the liquid mixture means the pH of the liquid mixture measured at 25 ℃ and 1 atm.
The type of acid may be conventionally selected so long as the acid does not chemically interact with the components of the reaction system (including the reactants, optional solvent, and reaction products) under the oxidation reaction conditions. Generally, the acid may be an inorganic acid and/or an organic acid, such as one or more of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, formic acid, and acetic acid, and is preferably hydrochloric acid and/or sulfuric acid. Either pure acid or an aqueous acid solution may be used. The mixing of the acid with the phenol and the oxidizing agent and other components of the liquid mixture (e.g., solvent) can be carried out either inside the reactor or outside the reactor.
According to the method of the present invention, the oxidation reaction conditions are not particularly limited and may be conventionally selected in the art. Generally, the oxidation reaction conditions include: the temperature may be from 10 to 180 ℃, preferably from 30 to 170 ℃, more preferably from 30 to 90 ℃; the pressure may be in the range of 0 to 2MPa, preferably 0.1 to 1.5MPa, in terms of gauge pressure.
The process according to the invention may also comprise a step of separating the benzenediol from the mixture obtained. The hydroquinone can be separated from the resulting mixture by various methods commonly used in the art, and the present invention is not particularly limited.
The present invention will be described in detail with reference to examples.
In the following examples and comparative examples, all reagents used were commercially available analytical grade reagents, and the pressures were measured by gauge pressure.
The discharging agents of the following preparation examples and preparation examples were obtained as follows, and the activity of titanium silicalite molecular sieves (including the discharging agent of titanium silicalite molecular sieves and the freshness agent of titanium silicalite molecular sieves) was measured by the following method.
The TS-1 molecular sieves (prepared as described in Zeolite, 1992, vol.12 2 2.1%) was placed in a 100mL slurry bed reactor with continuous feed and membrane separation means, and a mixture of water and 30wt% hydrogen peroxide (water to hydrogen peroxide volume ratio of 10: 9) A mixture of cyclohexanone and tert-butanol was added at a rate of 10.5mL/h (the volume ratio of cyclohexanone to tert-butanol was 1:2.5 Adding 36wt% ammonia water at a speed of 5.7mL/h, simultaneously adding the three material flows, continuously discharging at corresponding speed, maintaining the reaction temperature at 80 ℃, sampling the product after the reaction is stable, analyzing the composition of the liquid phase by using a gas chromatography method every 1 hour, calculating the conversion rate of cyclohexanone by using the following formula, and using the conversion rate as the activity of the titanium silicalite molecular sieve. Conversion of cyclohexanone = [ (molar amount of cyclohexanone added-not) molar amount of cyclohexanone reacted)/molar amount of cyclohexanone added]×100％。
The cyclohexanone conversion, measured for the first time, i.e. 1h, was its initial activity, which was 99.5%. After a period of about 168 hours, the cyclohexanone conversion rate is reduced from the initial 99.5% to 50%, the catalyst is separated and regenerated by roasting (roasting at 570 ℃ for 4 hours in air atmosphere), and then the catalyst is continuously used in cyclohexanone ammoximation reaction, the step is repeatedly carried out until the activity after regeneration is lower than 50% of the initial activity, at the moment, the inactivated ammoximation catalyst sample is used as the discharging agent of the invention, and the discharging agents SH-1 (the activity is 50%), SH-2 (the activity is 40%), SH-3 (the activity is 25%) and SH-4 (the activity is 10%) are sequentially obtained according to the method.
The pore volume and pore size distribution of the sample were measured on a Micromeritics ASAP2405 static nitrogen adsorption apparatus, and the specific data are shown in Table 1.
The elemental compositions of the samples, such as vanadium and silicon, were measured on a 3271E model X-ray fluorescence spectrometer, manufactured by Nippon Denshi electric motors Co., ltd., and the data are shown in Table 1.
In the present invention, the surface Si/Ti ratio was measured by an ESCALB 250 type X-ray photoelectron spectrometer manufactured by Thermo Scientific, and the bulk Si/Ti ratio was measured by a 3271E type X-ray fluorescence spectrometer manufactured by Nippon chemical industries, ltd., and the surface Si/Ti ratio/bulk Si/Ti ratio is shown in Table 1.
The Fourier transform infrared absorption spectrum of the sample is measured on a Nicolet 8210 type Fourier infrared spectrometer, KBr tablets (the sample accounts for 1 wt%) are adopted under vacuum, and the test range is 400-1400cm -1 。
In the following examples and comparative examples, the composition of the reaction mixture obtained by the contact was measured by gas chromatography, and on the basis of this, the phenol conversion, the effective utilization of the oxidizing agent and the selectivity for hydroquinone were calculated by the following formulas, respectively.
Phenol conversion (%) = [ (molar amount of phenol added-molar amount of unreacted phenol)/molar amount of phenol added ] × 100%;
the effective utilization rate of the oxidant (%) = [ the molar amount of the diphenol produced by the reaction/(the molar amount of the oxidant added-the molar amount of the unreacted oxidant) ] × 100%;
hydroquinone selectivity (%) = [ molar amount of hydroquinone produced by reaction/(molar amount of phenol added-molar amount of unreacted phenol) ] × 100%.
Preparation examples 1 to 12 and preparation examples 1 to 4 are illustrative of the molecular sieves of the present invention and the methods of preparing the same.
Preparation example 1
This preparation example illustrates the conventional process of preparing a titanium silicalite molecular sieve sample containing no vanadium by hydrothermal crystallization using silicalite as a silicon source.
Tetraethyl orthosilicate, titanium isopropoxide and tetrapropylammonium hydroxide are mixed, and proper amount of distilled water is added for stirring and mixing, wherein the molar composition in a reaction system is tetraethyl orthosilicate: titanium isopropoxide: tetrapropylammonium hydroxide: water =100:5:10:200, wherein tetraethyl orthosilicate is SiO 2 Counting; hydrolyzing at normal pressure and 60 deg.C for 1.0h, stirring at 75 deg.C for 3h, placing the mixed solution in a stainless steel sealed reaction kettle, and standing at 170 deg.C for 3d to obtain crystallized product mixture; filtering the mixture, washing with water, drying at 110 deg.C for 60min to obtain molecular sieve raw powder, and calcining at 550 deg.C for 3h to obtain titanium-silicon molecular sieve D-1 with XRD crystal phase of MFI structure.
Preparation example 2
This preparation example illustrates the conventional process for preparing a sample of a titanium silicalite molecular sieve containing vanadium by hydrothermal crystallization using a silicalite as a silicon source.
Tetraethyl orthosilicate, ammonium metavanadate, titanium isopropoxide and tetrapropylammonium hydroxide are mixed, and a proper amount of distilled water is added for stirring and mixing, wherein the molar composition in a reaction system is tetraethyl orthosilicate: titanium isopropoxide: ammonium metavanadate: tetrapropylammonium hydroxide: water =100:5:2:10:200 of tetraethyl orthosilicate is SiO 2 Counting; hydrolyzing at normal pressure and 60 deg.C for 1.0h, stirring at 75 deg.C for 3h, placing the mixed solution in a stainless steel sealed reaction kettle, and standing at 170 deg.C for 3d to obtain crystallized product mixture; filtering the mixture, washing with water, drying at 110 deg.C for 60min to obtain molecular sieve raw powder, and calcining at 550 deg.C for 3 hr to obtain directly hydrothermally crystallized V-Ti-Si molecular sieve D-2, which has an XRD crystallographic phase diagram consistent with that of preparation 1, which is an MFI structure.
Preparation example 3
This preparation illustrates the impregnation of a vanadium-loaded sample of the titanium silicalite molecular sieve prepared in preparation 1.
Mixing the titanium silicalite molecular sieve prepared in preparation example 1 with an ammonium metavanadate aqueous solution, wherein the mass ratio of the titanium silicalite molecular sieve to the ammonium metavanadate to the water is 10.
Preparation example 4
This preparation illustrates the impregnation of a vanadium-loaded sample with the discharging agent SH-2.
Mixing a discharging agent SH-2 with an ammonium metavanadate aqueous solution, wherein the mass ratio of the titanium silicalite molecular sieve to the ammonium metavanadate to the water is 10.5.
Preparation of example 1
Mixing and pulping the deactivated cyclohexanone oximation catalyst SH-2 and 1mol/L hydrochloric acid aqueous solution at normal temperature (20 ℃, the same for the other preparation examples and preparation examples) and normal pressure (0.1 MPa, the same for the other preparation examples and preparation examples), and then mixing and stirring the mixed pulp at 80 ℃ for 12 hours; after solid-liquid separation, mixing the solid, vanadium source ammonium metavanadate, titanium source titanium sulfate and sodium hydroxide aqueous solution (pH is 12), putting the mixed solution into a stainless steel sealed reaction kettle, and treating for 12 hours at 170 ℃, wherein the material quality composition is inactivated cyclohexanone oximation catalyst: a titanium source: a vanadium source: acid: alkali: water =100:1:1:10:5:250, deactivated cyclohexanone oximation catalyst with SiO 2 Acid is calculated as H + Calculated as OH, base - The titanium source is calculated as TiO 2 And (6) counting. Filtering the obtained product, washing with water, oven drying at 110 deg.C for 120min, and calcining at 550 deg.C for 3 hr to obtain molecular sieve S-1 with XRD crystal phase diagramIn line with preparation example 1, it is illustrated that a molecular sieve having the MFI structure is obtained.
Preparation of example 2
Firstly, mixing and pulping the inactivated cyclohexanone oximation catalyst SH-3 and 5mol/L hydrochloric acid solution at normal temperature and normal pressure, and then mixing and stirring the mixed slurry at 60 ℃ for 1h; after solid-liquid separation, mixing solid, vanadium tetrachloride as a vanadium source, tetrabutyl titanate as a titanium source and tetrapropyl ammonium hydroxide aqueous solution (pH is 10), putting the mixed solution into a stainless steel sealed reaction kettle, and treating for 12 hours at 150 ℃, wherein the material comprises the following components in mass: a titanium source: a vanadium source: acid: alkali: water =100:2:0.5:15:15:200 deactivated cyclohexanone oximation catalyst with SiO 2 Measured as H, acid + Calculated as OH, base - The titanium source is calculated as TiO 2 And (6) counting. The product was then recovered according to the procedure of preparation example 1 to obtain molecular sieve S-2, the XRD crystallography of which is consistent with that of preparation example 1.
Preparation of example 3
Under normal temperature and normal pressure, mixing and pulping the inactivated cyclohexanone oximation catalyst SH-4 and 8mol/L nitric acid aqueous solution, and then mixing and stirring the mixed slurry at 100 ℃ for 2 hours; after solid-liquid separation, mixing the solid, vanadium source sodium vanadate, titanium source titanium sulfate and sodium hydroxide aqueous solution (pH is 14), putting the mixed solution into a stainless steel sealed reaction kettle, and carrying out hydrothermal treatment for 18h at 140 ℃, wherein the material quality composition is an inactivated cyclohexanone oximation catalyst: a titanium source: a vanadium source: acid: alkali: water =100:5:2:10:15:600 deactivated Cyclohexanone oximation catalyst with SiO 2 Measured as H, acid + Calculated as OH, base - The titanium source is calculated as TiO 2 And (6) counting. The product was then recovered according to the method of preparation example 1 to obtain molecular sieve S-3, the XRD crystal phase diagram of which was identical to that of preparation example 1.
Preparation of example 4
Firstly, mixing and pulping the inactivated cyclohexanone oximation catalyst SH-1 and 5mol/L sulfuric acid aqueous solution at normal temperature and normal pressure, and then mixing and stirring the mixed slurry at 120 ℃ for 1h; after solid-liquid separation, mixing the solid, vanadium source ammonium metavanadate, titanium source titanium sulfate and n-butylamine aqueous solution (pH is 12.0)And (3) placing the mixed solution into a stainless steel sealed reaction kettle, and treating for 12h at 170 ℃, wherein the material quality composition is an inactivated cyclohexanone oximation catalyst: a titanium source: a vanadium source: acid: alkali: water =100:1:1:2:2:50, deactivated Cyclohexanone oximation catalyst with SiO 2 Measured as H, acid + Calculated by alkali in N and titanium source in TiO 2 And (6) counting. And filtering the obtained product, washing with water, drying at 110 ℃ for 120min, and roasting at 550 ℃ for 3h to obtain the molecular sieve S-4, wherein an XRD (X-ray diffraction) crystal phase diagram of the molecular sieve S-4 is consistent with that of the preparation example 1.
Preparation of example 5
Firstly, mixing and pulping deactivated cyclohexanone oximation catalyst SH-2 and 2mol/L perchloric acid aqueous solution at normal temperature and normal pressure, and then mixing and stirring the mixed pulp at 70 ℃ for 5 hours; after solid-liquid separation, mixing the solid, vanadium source ammonium metavanadate, titanium source titanium sulfate and ammonia water (pH is 11), putting the mixed solution into a stainless steel sealed reaction kettle, and treating for 12 hours at 170 ℃, wherein the material quality composition is inactivated cyclohexanone oximation catalyst: a titanium source: a vanadium source: acid: alkali: water =100:10:1:5:20:100, deactivated Cyclohexanone oximation catalyst with SiO 2 Acid is calculated as H + The alkali is calculated as N, and the titanium source is calculated as TiO 2 And (6) counting. And filtering the obtained product, washing with water, drying at 110 ℃ for 120min, and then roasting at 550 ℃ for 3h to obtain the molecular sieve S-5, wherein an XRD crystal phase diagram of the molecular sieve S-5 is consistent with that of the preparation example 1.
Preparation of example 6
Firstly, mixing and pulping the inactivated cyclohexanone oximation catalyst SH-2 and 15mol/L phosphoric acid aqueous solution at normal temperature and normal pressure, and then mixing and stirring the mixed slurry at 180 ℃ for 3 hours; after solid-liquid separation, mixing the solid, vanadium-source potassium metavanadate, titanium-source titanium sulfate and a sodium hydroxide aqueous solution (pH is 14), putting the mixed solution into a stainless steel sealed reaction kettle, and treating for 6 hours at 150 ℃, wherein the material comprises the following components in mass: a titanium source: a vanadium source: acid: alkali: water =100:5:2:10:15:600 deactivated Cyclohexanone oximation catalyst with SiO 2 Measured as H, acid + Calculated as OH as base - The titanium source is calculated as TiO 2 And (6) counting. The product was then recovered according to the method of preparation example 1,molecular sieve S-6 was obtained, the XRD phase diagram of which was in accordance with preparation example 1.
Preparation of example 7
Molecular sieves were prepared according to the method of preparative example 3, except that in the material mass composition, the deactivated cyclohexanone oximation catalyst: acid =100:5, obtaining the molecular sieve S-7, wherein the XRD crystal phase diagram of the obtained sample is consistent with that of the preparation example 1.
Preparation of example 8
Molecular sieves were prepared according to the method of preparative example 3, except that in the material mass composition, the deactivated cyclohexanone oximation catalyst: acid =100:100, obtaining the molecular sieve S-8, wherein the XRD crystal phase diagram of the obtained sample is consistent with that of the preparation example 1.
Preparation of example 9
The molecular sieve was prepared according to the method of preparation example 2, except that the discharging agent SH-3 was calcined and then subjected to subsequent pulping, heat treatment processes, wherein the calcination conditions included: and (3) roasting for 4 hours at 570 ℃ in an air atmosphere to obtain the molecular sieve S-9, wherein the XRD crystal phase diagram of the obtained sample is consistent with that of the preparation example 1, and the XRD crystal phase diagram of the obtained sample is consistent with that of the preparation example 1.
Preparation of example 10
A molecular sieve was prepared according to the method of preparation example 2 except that SH-1 was used as a discharging agent and the other conditions were the same, to obtain molecular sieve S-10, and the XRD crystal phase diagram of the obtained sample was identical to that of preparation example 1.
Preparation of example 11
A molecular sieve was prepared according to the method of preparation example 2, except that the order of addition of the starting materials was changed:
mixing and pulping inactivated cyclohexanone oximation catalyst SH-3 and 5mol/L hydrochloric acid solution at normal temperature and normal pressure, then mixing and stirring the mixed slurry at 60 ℃ for 1h, carrying out solid-liquid separation to obtain a solid, mixing vanadium source ammonium metavanadate and tetrapropyl ammonium hydroxide aqueous solution (the pH value is 10) to obtain a mixed solution, mixing the solid, tetrabutyl titanate and the mixed solution, putting the mixed solution into a stainless steel sealed reaction kettle, and treating the mixed solution at 150 ℃ for 12h, wherein the material composition by mass is the inactivated cyclohexanone oximation catalyst: a titanium source: a vanadium source: acid: alkali: water =100:2:0.5:15:15:200 deactivated cyclohexanone oximation catalyst with SiO 2 Measured as H, acid + Calculated as OH, base - The titanium source is calculated as TiO 2 And (6) counting. The product was then recovered according to the procedure of preparation example 1 to obtain molecular sieve S-11, the XRD crystal phase diagram of which was identical to that of preparation example 1.
Preparation of example 12
A molecular sieve was prepared according to the method of preparation example 2, except that tetrabutyl titanate derived from titanium was not added during the second heat treatment. The product was then recovered according to the procedure of preparation example 1 to obtain molecular sieve S-12, the XRD crystallography of which is consistent with that of preparation example 1.
TABLE 1
In table 1:
a = nV/nTi, nV is the amount of vanadium element of the molecular sieve, and nTi is the amount of titanium element of the molecular sieve;
B＝I 960 /I 800 ，I 960 the infrared absorption spectrum of the molecular sieve is 960cm -1 Absorption intensity in the vicinity, I 800 The infrared absorption spectrum of the molecular sieve is 800cm -1 Absorption strength in the vicinity;
C＝X 1-1.8 /X 0.4-0.9 ，X 0.4-0.9 the ratio of the pore diameter of the micropores of the molecular sieve in the range of 0.4-0.9nm to the total pore diameter distribution, X 1-1.8 The proportion of the micropore diameter of the molecular sieve in the range of 1-1.8nm to the total micropore diameter distribution amount is adopted;
D＝T w /T k ，T w is the micropore volume, T, of the molecular sieve k Is the total pore volume of the molecular sieve;
silicon: titanium: vanadium refers to the silicon element: titanium element: molar ratio of vanadium element.
Example 1
Phenol, an oxidizing agent, methanol as a solvent and the molecular sieve S-1 prepared in preparation example 1 as a catalyst were continuously fed into a moving bed reactor, respectively, to perform a contact reaction. Wherein, phenol is fed from a lower feed inlet of the reactor, and a mixture of an oxidant and a solvent and a catalyst are respectively fed into the reactor from a liquid-phase feed inlet and a solid-phase feed inlet which are positioned at the top of the reactor. Wherein the oxidant is 30 weight percent of hydrogen peroxide, and the molar ratio of phenol to the oxidant calculated by hydrogen peroxide is 1:1.5, the mass ratio of phenol to methanol as solvent is 1:7, the mass ratio of the phenol to the catalyst is 10:1, the feeding rate of phenol was 50mL/min, the temperature in the reactor was 60 ℃ and the pressure in the reactor was 0.5MPa. In the operation process, the catalyst output from the bottom of the reactor is directly recycled without regeneration.
And (3) carrying out gas chromatography analysis on reaction mixtures obtained 0.5h and 12h after the reaction starts, and calculating the conversion rate of phenol, the effective utilization rate of an oxidant and the selectivity of hydroquinone. The results are listed in table 2.
Comparative example 1
The molecular sieve D-1 prepared in preparation example 1 was pelletized into 10-20 mesh particles and loaded into the catalyst bed of a stainless steel fixed bed microreactor (a reactor containing a layer of catalyst with a loading of 10mL and a reactor Gao Jingbi of 15), phenol, an oxidant and methanol as a solvent were fed into the reactor from the bottom of the reactor to contact the catalyst bed at a temperature of 60 ℃ and a pressure of 0.5MPa, and a reaction mixture was obtained from the top of the reactor. Wherein the oxidant is 30 weight percent of hydrogen peroxide, and the molar ratio of phenol to the oxidant calculated by hydrogen peroxide is 1:1.5, the mass ratio of phenol to methanol as solvent is 1:7, the liquid hourly volume space velocity of the phenol is 2.5h -1 。
And (3) carrying out gas chromatography analysis on reaction mixtures obtained 0.5h and 12h after the reaction starts, and calculating the conversion rate of phenol, the effective utilization rate of an oxidant and the selectivity of hydroquinone. The results are listed in table 2.
Example 2
Phenol, an oxidizing agent, methanol as a solvent and the molecular sieve S-2 prepared in preparation example 2 as a catalyst were continuously fed into a moving bed reactor, respectively, to perform a contact reaction. Wherein, phenol is fed from a lower feed inlet of the reactor, and a mixture of an oxidant and a solvent and a catalyst are respectively fed into the reactor from a liquid-phase feed inlet and a solid-phase feed inlet which are positioned at the top of the reactor. Wherein the oxidant is 30 weight percent of hydrogen peroxide, and the molar ratio of phenol to the oxidant calculated by hydrogen peroxide is 1:1, the mass ratio of phenol to methanol as a solvent is 1:20, the mass ratio of phenol to catalyst is 20:1, the feeding rate of phenol was 40mL/min, the temperature in the reactor was 50 ℃ and the pressure in the reactor was 1MPa. In the operation process, the catalyst output from the bottom of the reactor is directly recycled without regeneration.
And (3) carrying out gas chromatography analysis on reaction mixtures obtained 0.5h and 12h after the reaction starts, and calculating the conversion rate of phenol, the effective utilization rate of an oxidant and the selectivity of hydroquinone. The results are listed in table 2.
Example 3
Phenol, an oxidizing agent, methanol as a solvent and the molecular sieve S-3 prepared in preparation example 3 as a catalyst were continuously fed into a moving bed reactor, respectively, to perform a contact reaction. Wherein, phenol is fed from a lower feed inlet of the reactor, and a mixture of an oxidant and a solvent and a catalyst are respectively fed into the reactor from a liquid-phase feed inlet and a solid-phase feed inlet which are positioned at the top of the reactor. Wherein the oxidant is 30 weight percent of hydrogen peroxide, and the molar ratio of phenol to the oxidant calculated by hydrogen peroxide is 1: and 4, the mass ratio of the phenol to the methanol used as the solvent is 1:14, the mass ratio of phenol to catalyst is 15:1, the feeding rate of phenol was 30mL/min, the temperature in the reactor was 65 ℃ and the pressure in the reactor was 0.6MPa. In the operation process, the catalyst output from the bottom of the reactor is directly recycled without regeneration.
And (3) carrying out gas chromatography analysis on reaction mixtures obtained 0.5h and 12h after the reaction starts, and calculating the conversion rate of phenol, the effective utilization rate of an oxidant and the selectivity of hydroquinone. The results are listed in table 2.
Examples 4 to 12
The procedure of example 1 was followed, except that the molecular sieve S-1 obtained in production example 1 was replaced with the molecular sieves S-4 to S-12 obtained in production examples 4-12, respectively, of equal mass.
And (3) carrying out gas chromatography analysis on reaction mixtures obtained 0.5h and 12h after the reaction starts, and calculating the conversion rate of phenol, the effective utilization rate of an oxidant and the selectivity of hydroquinone. The results are listed in table 2.
Examples 13 to 16
The procedure of example 1 was followed, except that the molecular sieve S-1 obtained in production example 1 was replaced with the molecular sieves D-1 to D-4 obtained in production examples 1-4, respectively, of equal mass.
And (3) carrying out gas chromatography analysis on reaction mixtures obtained 0.5h and 12h after the reaction starts, and calculating the conversion rate of phenol, the effective utilization rate of an oxidant and the selectivity of hydroquinone. The results are listed in table 2.
Example 17
The procedure of example 1 was followed except that hydrochloric acid (28 wt% aqueous solution) was fed into the reactor through the auxiliary agent feed port provided at the top of the moving reactor in such an amount that the pH of the liquid-phase mixture formed of phenol, oxidizing agent and solvent was 5.5 (6.8 for the liquid-phase mixture formed of phenol, oxidizing agent and solvent). And (3) carrying out gas chromatographic analysis on reaction mixtures obtained 0.5h and 12h after the reaction starts, and calculating the conversion rate of phenol, the effective utilization rate of an oxidant and the selectivity of hydroquinone. The results are listed in table 2.
Example 18
The process of example 17 was followed except that hydrochloric acid was used in an amount such that the pH of the liquid-phase mixture formed from phenol, the oxidizing agent and the solvent was 4. And (3) carrying out gas chromatography analysis on reaction mixtures obtained 0.5h and 12h after the reaction starts, and calculating the conversion rate of phenol, the effective utilization rate of an oxidant and the selectivity of hydroquinone. The results are listed in table 2.
Example 19
The process of example 17 was followed except that hydrochloric acid was used in an amount such that the pH of the liquid-phase mixture formed from phenol, the oxidizing agent and the solvent was 2.5. And (3) carrying out gas chromatography analysis on reaction mixtures obtained 0.5h and 12h after the reaction starts, and calculating the conversion rate of phenol, the effective utilization rate of an oxidant and the selectivity of hydroquinone. The results are listed in table 2.
Example 20
The procedure was followed as in example 17, except that hydrochloric acid was replaced with aqueous ammonia (concentration of 30% by weight) in an amount such that the pH of the liquid-phase mixture formed from phenol, the oxidizing agent and the solvent was 8.5. And (3) carrying out gas chromatography analysis on reaction mixtures obtained 0.5h and 12h after the reaction starts, and calculating the conversion rate of phenol, the effective utilization rate of an oxidant and the selectivity of hydroquinone. The results are listed in table 2.
TABLE 2
It can be seen from the results in table 2 that the method for preparing hydroquinone provided by the present invention can improve the conversion rate of phenol, the effective utilization rate of the oxidant, the selectivity of hydroquinone and the stability of the catalyst. In addition, the optimized vanadium-titanium-silicon molecular sieve can further improve the conversion rate of phenol, the effective utilization rate of an oxidant, the selectivity of hydroquinone and the stability of a catalyst; by adopting the scheme of adjusting the pH of the liquid mixture by adding acid, the conversion rate of phenol, the effective utilization rate of the oxidant, the selectivity of hydroquinone and the stability of the catalyst can be further improved.
The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, numerous simple modifications can be made to the technical solution of the invention, including any suitable combination of specific features, and in order to avoid unnecessary repetition, the invention will not be described in detail in relation to the various possible combinations. Such simple modifications and combinations should be considered within the scope of the present disclosure as well.
Claims (25)
1. A method of making a benzenediol, the method comprising: contacting phenol, at least one oxidant, and a catalyst in a reaction zone of a moving bed reactor under oxidation reaction conditions;
wherein the catalyst contains a vanadium-titanium-silicon molecular sieve, and the vanadium-titanium-silicon molecular sieve comprises: vanadium, titanium, silicon and oxygen, wherein the molecular sieve satisfies X 1-1.8 /X 0.4-0.9 ＝C，0.2<C<1，X 0.4-0.9 The ratio of the pore diameter of the micropores of the molecular sieve in the range of 0.4-0.9nm to the distribution quantity of the total pore diameter, X 1-1.8 The proportion of the micropore diameter of the molecular sieve in the range of 1-1.8nm to the total micropore diameter distribution amount is adopted;
the molecular sieve satisfies nV/nTi = A, I 960 /I 800 = B, B = i (a + 1) nTi, wherein 0.1<A<10，0.2<B<1，0<I, nV is the molar weight of vanadium element in the molecular sieve, nTi is the molar weight of titanium element in the molecular sieve, I 960 The infrared absorption spectrum of the molecular sieve is 960cm -1 Absorption intensity in the vicinity, I 800 The infrared absorption spectrum of the molecular sieve is 800cm -1 Absorption strength in the vicinity;
the molecular sieve satisfies T w /T k ＝D，0.2<D<0.5，T w Is the micropore volume of the molecular sieve, T k Is the total pore volume of the molecular sieve;
silicon element of the molecular sieve: titanium element: the molar ratio of vanadium elements is 100: (0.1-10): (0.01-5);
the surface silicon-titanium ratio of the molecular sieve is not lower than the bulk silicon-titanium ratio, and the silicon-titanium ratio refers to the molar ratio of silicon oxide to titanium oxide.
2. The method of claim 1, wherein the contacting is performed in the presence of at least one solvent; the mass ratio of the solvent to the phenol is (1-100): 1.
3. the method of claim 2, wherein,
the solvent is at least one selected from water, C1-C6 alcohol, C3-C8 ketone, C2-C8 nitrile and C2-C8 carboxylic acid.
4. The method of claim 3, wherein,
the solvent is acetic acid, acetone, methanol and water.
5. The method of claim 1, wherein,
the molar ratio of phenol to oxidant is 1: (0.1-10); and/or
The mass ratio of the phenol to the catalyst is 0.1-50:1.
6. the method of claim 5, wherein,
the molar ratio of phenol to oxidant is 1: (0.2-5); and/or
The mass ratio of the phenol to the catalyst is 1-50:1.
7. the process of any one of claims 1 to 6, further comprising feeding at least one acid to the reaction zone in an amount such that the liquid mixture contacted with the catalyst has a pH of from 3 to 5.5.
8. The method of claim 7, wherein,
the acid is added in an amount such that the pH of the liquid mixture in contact with the catalyst is from 4 to 5.5.
9. The method of claim 1, wherein,
the molecular sieve satisfies 0.25-C-cloth-0.85.
10. The method of claim 1, wherein,
the molecular sieve satisfies 0.2-cloth A-cloth and 5, and 0.3-cloth B-cloth and 0.8.
11. The method of claim 1, wherein,
the molecular sieve satisfies 0.25-woven D-woven 0.45.
12. The method of claim 1, wherein,
silicon element of the molecular sieve: titanium element: the molar ratio of the vanadium element is 100: (0.2-5): (0.2-2.5).
13. The method of claim 1, wherein,
the ratio of the surface silicon-titanium ratio to the bulk silicon-titanium ratio is 1.2-5.
14. The method of claim 13, wherein,
the ratio of the surface silicon-titanium ratio to the bulk silicon-titanium ratio is 1.5-4.5.
15. The method of any one of claims 1 to 6 and 8 to 14, wherein the method for preparing the vanadium-titanium-silicon molecular sieve comprises the following steps:
(1) Mixing a catalyst containing a titanium silicalite molecular sieve with an acid solution, carrying out first heat treatment on the obtained mixture, and separating to obtain a first solid;
(2) And mixing the first solid, the vanadium source, the alkali source and the water, and then carrying out second heat treatment.
16. The method of claim 15, wherein,
the catalyst containing the titanium silicalite molecular sieve is a discharging agent of an ammoximation reaction device.
17. The method of claim 15, wherein,
the temperature of the first heat treatment is 40-200 ℃; the temperature of the second heat treatment is 100-200 ℃.
18. The method of claim 15, wherein,
the time of the first heat treatment is 0.5-360h; the time of the second heat treatment is 0.5-96h.
19. The method of claim 15, wherein the acid solution has a concentration>0.1mol/L; catalyst containing titanium silicalite: a vanadium source: acid: alkali source: the mass ratio of water is 100: (0.1-10): (0.005-50): (0.5-50): (20-1000) in which the catalyst containing titanium-silicon molecular sieve is SiO 2 ˉ
Measured as H, acid + The alkali source is calculated as N or OH.
20. The method of claim 15, wherein,
the acid is organic acid and/or inorganic acid; the alkali source is one or more of ammonia, aliphatic amine, aliphatic alcohol amine and quaternary ammonium hydroxide; the vanadium source is one or more of vanadium oxide, vanadium acid, vanadate, vanadium halide, vanadium carbonate, vanadium nitrate, vanadium sulfate, vanadium phosphate and vanadium hydroxide.
21. The method of any one of claims 16-20, wherein a titanium source is added during the second heat treatment, the titanium source being selected from inorganic titanium salts and/or organic titanates.
22. The method of any one of claims 16-20,
the step (2) is carried out according to the following steps: and mixing a vanadium source, an alkali source and water to obtain a mixture, and mixing the mixture, a titanium source and the first solid to perform the second heat treatment.
23. The method of claim 21, wherein,
the mass ratio of the catalyst containing the titanium silicalite molecular sieve to the titanium source is 100: (0.1-10), wherein the catalyst containing titanium silicalite molecular sieve is SiO 2 The titanium source is calculated as TiO 2 And (6) counting.
24. The method of any of claims 1-6, wherein the oxidation reaction conditions comprise: the temperature is 10-180 ℃; the pressure in the reaction zone of the reactor is 0-2MPa in gauge pressure.
25. The method of any one of claims 1-6,
at least a portion of the catalyst removed from the reaction zone is recycled to the reaction zone after optional regeneration.
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| CN107986294A (en) * | 2016-10-27 | 2018-05-04 | 中国石油化工股份有限公司 | A kind of Titanium Sieve Molecular Sieve containing vanadium and its synthetic method and application |
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