CN1415414A

CN1415414A - Catalyzer utilized to synthesize oxalate and its preparation method

Info

Publication number: CN1415414A
Application number: CN 02146105
Authority: CN
Inventors: 郭俊怀; 王敬中; 翟成契; 沙昆源
Original assignee: Nankai University
Current assignee: Nankai University
Priority date: 2002-10-31
Filing date: 2002-10-31
Publication date: 2003-05-07
Anticipated expiration: 2022-10-31
Also published as: CN1150992C

Abstract

A catalyst for synthesizing oxalate is prepared by using delta-Al2O3 as carrier to carry the active components Pd, Fe and La. The said carrier is prepared from alpha-AlO(OH) or Al salt.

Description

Catalyst for synthesizing oxalate and preparation method thereof

Technical Field

The invention relates to synthesis of oxalate, in particular to a catalyst for synthesizing oxalate and a preparation method thereof. The present invention relates to a catalyst for catalytic synthesis of oxalate from carbon monoxide and nitrous acid ester and its preparation method, and provides a delta-Al catalyst suitable for said reaction and prepared by using different methods₂O₃The crystal form is a carrier, and two or more active components of metal are loaded on the carrier, so that the activity and the service life of the catalyst can be effectively improved by mutual matching.

Background

Oxalate ester can be used for preparing oxalic acid, oxamide, glycol and intermediates of certain drugs and dyes, is an important basic chemical raw material and has important function in carbon-one chemistry, and the discovery of D.M.Fenton et Al in 1965 that carbon monoxide is subjected to coupling reaction in alcohol medium to obtain α -Al₂O₃The carrier is palladium metal as catalyst to synthesize oxalic diester. Then, considerable expenses are invested in the united states and japan, and research and development are carried out along this concept.

The preparation process of the catalyst uses different active metal components to carry out different proportions, the composition of reaction materials, the reaction temperature, the flow rate of carrier gas, the improvement of equipment and the like, and the used carriers are α -Al₂O₃Or gamma-Al₂O₃The crystal form is carrier ((1) Chenoheshen Cichlon Xue Biao Nature gas chemical 1995 Vol 20(2)5-9, He Fei Gangzhenghong Songyu Hua Genghui catalytic Xuanhui Ching 2002523 Vol (3) 223-. Chinese patent CN 1066070C describes the use of activated alumina, but with Al as given₂O₃Surface area of 6-7M²Per g, should be α -Al₂O₃EP 0108359A 1 also uses α -Al₂O₃And (4) preparing a carrier.

We found in our experiments to use α -Al₂O₃Or gamma-Al₂O₃The catalyst prepared by using the crystal form as a carrier has lower yield or poorer service life due to the pore structure and strength of the carrier. As shown in table one and table two: table one: catalyst prepared from carriers with different crystal forms, yield and service life comparison

Carrier crystal form	Yield of	Life span
Carrier crystal form	Yield of	Life span	γ-Al₂O₃	1.22g/lg.^※1h	Difference (D)
δ-Al₂O₃	3.29g/1g1h	Good taste	γ-Al₂O₃	1.22g/lg.^※1h	Difference (D)
δ-Al₂O₃	3.29g/1g1h	Good taste	δ-Al₂O₃+α-Al₂O₃	2.33g/1g1h	Is preferably used

1g.^※: the same applies to 1g of catalyst. Table two: structural indexes of carriers of different crystal forms (figure 2: mercury intrusion diagram)

Structural item	γ-Al₂O₃	δ-Al₂O₃	δ-Al₂O₃+α-Al₂O₃
Structural item	γ-Al₂O₃	δ-Al₂O₃	δ-Al₂O₃+α-Al₂O₃	Cumulative pore volume (ml/g)	0.3931	0.5578	0.5110
Total pore specific surface area (sq-m/g)	166.530	68.876	62.117	Cumulative pore volume (ml/g)	0.3931	0.5578	0.5110
Total pore specific surface area (sq-m/g)	166.530	68.876	62.117	Diameter of middle hole (um)	0.0089	0.0376	0.0439
Apparent Density (g/ml)	1.3918	1,1515	1.2483	Diameter of middle hole (um)	0.0089	0.0376	0.0439
Apparent Density (g/ml)	1.3918	1,1515	1.2483	Skeleton density (g/ml)	3.0736	3.2196	3.4480

Disclosure of Invention

The invention aims to provide a catalyst for synthesizing oxalate and a preparation method thereof, which can overcome the defects of the prior art and adopts delta-Al₂O₃The crystal form is used as a carrier, has the most appropriate pore structure and strength, and the obtained catalyst has better activity and service life under the same conditions

The invention uses delta-Al₂O₃The crystal form is used as a carrier to load a catalyst consisting of Pd, Fe and La active components. The atomic ratio of the active ingredients is 3-0.5: 2-0.5 respectively. The delta-Al₂O₃The pore structure of the carrier is: total pore volume (ml/g) 0.4-0.9; total pore surface area (m)²Per g)60 to 100; average pore diameter (mum) of 0.03-0.05; apparent density (g/ml) 0.77-1.2; the skeleton density (g/ml) is 2.5-3.5.

Delta-Al of the invention₂O₃The preparation method of the carrier comprises the following steps:

1) preparation of delta-Al from pseudo-boehmite₂O₃Carrier

Crushing pseudo-boehmite by 200-400^#Sieving with a sieve, adding graphite powder 1-3% of the powder and CaCO 1-3% of the powder₃Then adding dilute HNO accounting for 45 percent of the powder amount₃(concentration is 1-3%), stirring uniformly, and rolling. Extruding into 2.5mm strip with a strip extruder, and naturally drying4 hours, drying at 120 ℃, and roasting according to a certain temperature rising program.

(2) From AlCl₃·6H₂Preparation of delta-Al from O₂O₃And (3) a carrier.

5 parts of AlCl with the concentration of 8.6 percent (weight percentage)₃·6H₂O solution with 1 part of 1% NH₄The OH solution is added into the reactor under stirring, and the reaction is carried out at 70 ℃ and the pH value is 7-8. Standing for 30 minutes, filtering, washing with water until no Cl is detected^-Until now. Drying at 120 deg.C, adding graphite and CaCO in sequence according to the proportion of (1)₃Dilute HNO₃Rolling, extruding into cylindrical strips with diameter of 2.5mm, naturally drying for 5 hr, drying at 120 deg.C, and calcining according to a certain program.

Usable Al₂(SO₄)₃·6H₂O、Al(NO₃)₃·6H₂O instead of AlCl₃·6H₂Preparation of delta-Al from O₂O₃A carrier in a crystal form.

The roasting temperature-rising program is as follows:

keeping the temperature at 200 ℃ for 20-40 min, keeping the temperature at 250 ℃ for 20-35 min, keeping the temperature at 300 ℃ for 2-4 h

Keeping the temperature at 500 ℃ for 20-40 min, keeping the temperature at 600 ℃ for 20-30 min, and keeping the temperature at 900 ℃ for 4-9 hours

Naturally cooling to room temperature. X-ray diffraction pattern 1 shows that 45.4 DEG is delta-Al₂O₃Minor main peak of (2).

The invention uses delta-Al₂O₃The preparation method of the catalyst used as the carrier comprises the following steps:

1) the halide, nitrate and sulfate of Pd, Fe and La are used to prepare impregnating solution according to the measurement, and acid is added to control the PH value between 1 and 4.5, so as to prevent the influence of hydroxide precipitation generated by metal ion hydrolysis on the impregnation of the carrier.

2) Providing delta-Al with appropriate pore structure and strength₂O₃The carrier is added into the impregnation liquid and soaked for 2-8 hours.

3) Separating, drying, soaking in mixed alkali solution at 70 deg.C for 4-6 hr, and washing to remove negative ions.

4)Drying, and treating with H at 550 ℃ under 220-₂Reducing for 3-5 hours to prepare different types of catalysts.

The invention uses delta-Al₂O₃The catalyst used as a carrier is applied to the reaction of synthesizing oxalate by gas phase catalysis of carbon monoxide and nitrite as follows:

coupling reaction: wherein: r alkyl (CH)₃-，C₂H₅-，C₄H₉-)

And (3) regeneration reaction:

the oxalate synthesis adopts a fixed bed device, the reaction tube is in a jacket structure, the innermost layer of the reaction tube is provided with a hard glass tube with the inner diameter of 10-20mm and the length of 300-350mm, 1-80ml of catalyst can be filled, and the top of the catalyst layer is additionally provided with glass fiber with the thickness of 100mm so as to preheat the reaction feed gas. The middle layer is filled with a heating white oil and mercury conductive meter (used for controlling temperature), the outer wall is wrapped with a layer of asbestos paper, a resistance wire is wound, the outermost layer is protected by asbestos cloth, and the temperature of a catalyst bed layer is controlled by a relay. The reaction tube has three outlets, the middle port in the top is inserted into ground thermometer to measure the temperature in the reaction area, the side port is connected to gasifying tube, the reaction material gas is mixed into the reactor, and the bottom has outflow product and tail gas port. Detecting with 102G gas chromatograph from Shanghai analytical instrument factory, and using 5A molecular sieve as chromatographic column filler with column length of 4 m.

The ratio of CO to RONO is generally controlled to be 15-30 to 10-15 (volume ratio), the contact time is 0.5-3 seconds, the activation temperature of the catalyst is 120-140 ℃, and the reaction temperature is 100-130 ℃.

With α -Al₂O₃Or gamma-Al₂O₃The crystal form is not the best choice, and the invention uses delta-Al₂O₃The crystal carrier has optimal pore structure and strength without special treatment and simple process. The catalyst obtained under the same conditions has better activity and service life. The proper pore structure of the catalyst is favorable for the diffusion of reactants and products. gamma-Al₂O₃The crystal form has large specific surface area due to a plurality of small pores, but the pore structure is not beneficial to the diffusion of reactants and products, so the activity is low. Because the skeleton density is low, the carrier strength is poor, and pulverization and inactivation are easy to cause. From delta-Al₂O₃+α-Al₂O₃In the mixed crystal form, α -Al appears along with the increase of the calcining temperature and the increase of the calcining time₂O₃The formation of crystal form, the cumulative pore volume and the specific surface area are reduced, which is also unfavorable for the improvement of the catalyst activity, but the skeleton density is high, and the strength of the catalyst can be properly increased. Two aspects in combination, whereas delta-Al₂O₃The crystal carrier has proper pore structure and strength, and the prepared catalyst has high activity and long service life.

Drawings

FIG. 1. delta. -Al₂O₃X-ray diffraction pattern of (a).

Fig. 2 mercury intrusion diagram (a) differential diagram (b) integral diagram.

Detailed Description

Example 1: preparation of delta-Al from pseudo-boehmite₂O₃And (3) a carrier.

Crushing 320 parts of pseudo-boehmite provided by three petroleum plants^#Sieving to obtain powder, adding the powder to obtain powder2 percent of graphite powder with the same mesh number and then 2 percent of CaCO (calcium carbonate) in the weight of the powder₃Mixing, adding dilute nitric acid (concentration of 2%) whose powder weight is 45%, stirring uniformly, rolling for several times, extruding out strip-like material whose diameter is 2.5mm by using strip-extruding machine, naturally drying for 4 hr, drying at 120 deg.C, and roasting according to the following heating program. Keeping the temperature at 200 ℃ for 20 minutes, keeping the temperature at 250 ℃ for 20 minutes, keeping the temperature at 300 ℃ for 2 hours, keeping the temperature at 500 ℃ for 30 minutes, keeping the temperature at 600 ℃ for 50 minutes, and keeping the temperature at 900 ℃ for 8 hours. Naturally cooling from 900 deg.C to room temperature.

Example 2: using AlCl₃·6H₂Preparation of delta-Al from O₂O₃Carrier

Taking the concentration of 8.5 percent (weight ratio))AlCl₃·6H₂5 parts of O solution and 1 part of 1% NH₄OH solution, stirring at 70 deg.C, adding into reactor, adjusting pH to 7-8 with 1% HCl, aging for 30 min, filtering, washing with distilled water until no Cl is detected^-Ions are removed. Oven drying at 120 deg.C, pulverizing, and sieving with 320 mesh sieve^#Mesh screen, as in example 1, with 1% graphite, 1% CaCO₃Mixing, adding 45% dilute nitric acid (concentration of 1%), stirring, grinding, extruding into 2.5mm strips, naturally drying for 6 hr, oven drying at 120 deg.C, and calcining at the following temperature. Keeping the temperature at 200 ℃ for 20 minutes, keeping the temperature at 250 ℃ for 20 minutes, keeping the temperature at 300 ℃ for 2 hours, keeping the temperature at 500 ℃ for 30 minutes, keeping the temperature at 600 ℃ for 50 minutes, and keeping the temperature at 900 ℃ for 8 hours. Naturally cooling from 900 deg.C to room temperature.

Example 3:

preparation of 0.1M FeCl₃And (3) solution.

With 1.6657g of PdCl₂And 1g of NaCl was added to make 100ml of the solution.

With 1g NaOH and 1.5g NaHCO₃To prepare 100ml of mixed alkali liquor.

Taking PdCl₂5ml of solution, FeCl₃Adding 4.7ml of the solution, adding 5ml of distilled water, stirring and mixing, and soaking 5g of gamma-Al₂O₃And 5 hours, separating and drying the crystal form carrier. Soaking in 5ml mixed alkali solution for 6 hr, filtering, and washing to remove Cl^-And (5) drying. With H at 540 deg.C₂And changing the original source for 4 hours. Fe. The atomic ratio of Pd is about 1: 1. Obtaining Pd-Fe/gamma-Al₂O₃A catalyst of the type (I) is provided.

2g of freshly prepared Pd-Fe/gamma-Al from example 3₂O₃Catalyst of type N₂The flow rate is 300 ml/min, the activation is carried out for 3 hours at 140 ℃, and the reaction temperature is 110 ℃ and 120 ℃. N is a radical of₂The flow rates of CO were 220 ml/min and 130 ml/min, respectively. The ratio of CO to RONO is controlled to be 15-30 to 10-15 (volume ratio). The average yield is 1.22g/1g-1h, the circulation is carried out twice, and the activity is reduced by half in the second circulation.

Example 4

Taking 5 parts of delta-Al₂O₃Support, 5ml of PdCl prepared in example 3 were added₂Solution, immersion for 4 hoursAdding 10ml of mixed alkali liquor, soaking for 5 hours at 70 ℃, filtering and drying. H at 300 DEG C₂And reducing for 3 hours. Taking 4.7ml FeCl₃Soaking the solution for 4 hours, then soaking the solution for 5 hours by using 5ml of mixed alkali liquor, filtering and washing the solution by water until no Cl is detected^-Ions. After drying, H is carried out at 500 DEG C₂Reducing for 4 hours to prepare Pd-Fe/delta-Al₂O₃A two-component catalyst. The atomic ratio of Pd to Fe is about 1: 1.

2g of newly prepared Pd-Fe/delta-Al are taken₂O₃The catalyst was evaluated under the evaluation conditions of example 3, and the average yield after evaluation was: 1.92g/1g-1 h.

Example 5:

with 3.487g of LaCl₃·7H₂O, to prepare 100ml LaCl₃The aqueous solution of (a) to (b),

PdCl prepared in example 3₂7ml of the solution, taking FeCl₃2.5ml of the solution, and newly prepared LaCl is taken₃Mixing 2.7ml of the solution, adjusting pH to 1.82 to obtain a mixed solution, and soaking 7g of delta-Al₂O₃+α-Al₂O₃Mixing crystal form carrier for 5 hr, separating solid, soaking in 8ml mixed alkali solution prepared in 3 for 5 hr, filtering, washing with water until no Cl is detected^-And finally, drying. Introducing H at 500 DEG C₂Reducing for 4 hours to obtain Pd-Fe-La/delta-Al₂O₃+α-Al₂O₃Three-component catalyst. The atomic ratio of La, Fe and Pd is about 1: 2.5.

Taking newly prepared Pd-Fe-La/delta-Al₂O₃+α-Al₂O₃Three component catalyst 2 grams, the catalyst was evaluated using the evaluation conditions of example 3. The average yield after evaluation was: 2.33g/1g-1h, the activity is slightly reduced after 3 times of circulation.

Example 6:

taking PdCl₂7ml of the solution, taking FeCl₃2.5ml of the solution, and LaCl was taken₃Mixing 2.7ml of the solution, adjusting pH to 1.82 to obtain a mixed solution, and soaking 7g of delta-Al₂O₃And (3) soaking the crystal form carrier for 6 hours. After drying, 10ml of mixed alkali liquor prepared in example 3 is taken and soaked for 4 hours at 70 ℃ and thenFiltering, washing with water until no Cl is detected^-. H at 500 DEG C₂Reducing for 4 hours to obtain Pd-Fe-La/delta-Al₂O₃The catalyst has an atomic ratio of La, Fe and Pd of about 1: 2.5.

Taking newly prepared Pd-Fe-La/delta-Al₂O₃2g of type catalyst, evaluation conditions were the same as in example 3, and average yield after evaluation: 3.29g/1g-1h, circulating for 3 times, and gradually increasing the activity.

Claims

1. A catalyst for synthesizing oxalate is characterized by that it is delta-Al₂O₃As carrier, Pd, Fe and La are loaded.

2. The catalyst for synthesizing oxalate according to claim 1, characterized in that the atomic ratio of the active ingredients Pd, Fe and La is 3-0.5: 2-0.5, respectively.

3. The catalyst for synthesizing oxalate according to claim 1, wherein said delta-Al is₂O₃The pore structure of the carrier is: total pore volume (ml/g) 0.4-0.9; total pore surface area (m)²Per g)60 to 100; average pore diameter (mum) of 0.03-0.05; apparent density (g/ml) 0.77-1.2; the skeleton density (g/ml) is 2.5-3.5.

4. The method for preparing a catalyst for synthesizing oxalate according to claim 1, comprising the steps of:

1) preparing a steeping fluid by using salts of Pd, Fe and La according to the dosage, wherein the PH value is 1-4.5;

2) beta-Al₂O₃Addinginto the steeping liquor, and soaking for 2-8 hours;

3) separating, oven drying, soaking in mixed alkaline solution at 70 deg.C for 4-6 hr, washing to remove negative ions,

4) drying, and treating with H at 550 ℃ under 220-₂Reducing for 3-5 hours.

5. Use according to claim 1 for closingOxalate-forming catalyst, characterized in that said delta-Al₂O₃The preparation method of the carrier comprises the following steps:

1) preparation of delta-Al from pseudo-boehmite₂O₃Carrier

Crushing pseudo-boehmite by 200-400^#Sieving with a sieve, adding graphite powder 1-3% of the powder and CaCO 1-3%₃Then adding dilute HNO accounting for 45 percent of the powder amount₃(the concentration is 1-3%), stirring evenly, rolling, extruding a strip body with the diameter of 2.5mm by a strip extruding machine, drying naturally for 4 hours, drying at 120 ℃, and roasting according to a temperature rising program; naturally cooling to room temperature;

2) from AlCl₃·6H₂Preparation of delta-Al from O₂O₃Carrier

5 portions of AlCl with the concentration of 8.6 percent₃·6H₂O solution and 1 part of NH with the concentration of 1 percent₄OH solution reaction, stirring at 70 deg.C, pH 7-8, standing for 30 min, suction filtering, washing with water until no Cl is detected^-Drying at 120 deg.C, adding graphite and CaCO in sequence according to the proportion of (1)₃Rolling and pressing the mixture into cylindrical thin strips with the diameter of 2.5mm, naturally drying the thin strips for 5 hours, drying the thin strips at 120 ℃ and roasting the thin strips according to the program; naturally cooling to room temperature.

6. The oxalate-synthesizing catalyst carrier according to claim 5, delta-Al₂O₃The preparation method is characterized in that the AlCl is adopted₃·6H₂O may be Al₂(SO₄)₃·6H₂O or Al (NO)₃)₃·6H₂And O is replaced.

7. The oxalate-synthesizing catalyst carrier according to claim 5, delta-Al₂O₃The preparation method is characterized in that the roasting temperature-rising program is as follows:

Keeping the temperature at 500 ℃ for 20-40 min, keeping the temperature at 600 ℃ for 20-50 min, and keeping the temperature at 900 ℃ for 4-9 h.

8. The method for using the catalyst for synthesizing oxalate according to claim 1, characterized in that it comprises the following steps: a fixed bed device is adopted, and a reaction tube has a jacket structure. The ratio of CO to RONO is controlled to be 15-30 to 10-15 (volume ratio), the contact time is 0.5-3 seconds, the activation temperature of the catalyst is 120-140 ℃, and the reaction temperature is 100-130 ℃.