CN102631943A - Iron-phosphorus-base catalyst for preparing bromomethane by methane oxybromination, and preparation method and application thereof - Google Patents

Abstract

A Fe-PO/SBA-15 catalyst for methane bromination oxidation to prepare methyl bromide and CO, the catalyst is composed of an active component and a carrier, and the active component is FePO ₄ , Fe ₂ P ₂ O ₇ or α-Fe ₃ ( One or more of P ₂ O ₇ ) ₂ ; the weight of the active component is 1.0-60.0% of the weight of the catalyst; the molar ratio of Fe/Si element in the catalyst is 0.001-1.0; the molar ratio of P/Si element in the catalyst is 1.0-5.0; the carrier is SBA-15 all-silicon molecular sieve; the specific surface area of the catalyst is 100-1500m ² /g, and the pore volume is 0.65-1.20m ³ /g. The preparation of the catalyst of the present invention takes iron salt, phosphoric acid [H ₃ PO ₄ ] and ethyl orthosilicate [(C ₂ H ₅ O) ₄ Si] as precursors, and triblock polymer [(EO) ₂₀ (PO ) ₇₀ (EO) ₂₀ ] (abbreviated as P123) is a template agent, the active component is introduced into the carrier by hydrothermal method, and then the Fe-PO/SBA- 15 catalysts.

Description

A kind of iron-phosphorus-based catalyst for methane bromination oxidation to prepare methyl bromide, preparation method and application thereof

technical field

The invention relates to a Fe-P-O/all-silicon molecular sieve SBA-15 catalyst used for methane bromination oxidation to prepare methyl bromide and CO, its preparation method and its use in preparing methyl bromide and CO from methane, oxygen and HBr aqueous solution. the

Background technique

Natural gas is considered to be the cleanest fossil energy. With the increasing energy consumption for human survival, how to convert natural gas into other chemical raw materials is a key issue to reduce human dependence on petroleum resources. At present, the main way of industrial utilization of natural gas is to firstly synthesize gas through steam recombination, and then realize the indirect conversion of natural gas into chemicals through the subsequent Fischer-Tropsch synthesis reaction. Due to the high energy consumption and complicated process of this process, only the application in large natural gas fields can produce economic benefits. Natural gas fields have the characteristics of scattered resources, and the distribution is mainly in small and medium-sized gas fields. This requires the development of a new technology for natural gas conversion with high efficiency, flexible operation and simple process. The development of an efficient catalytic system for methane activation is a key link. the

CN 1640864 disclosed earlier a method of converting methane into CH ₃ Br and CO through methane bromination oxidation reaction, and the latter is hydrolyzed to obtain methanol or dimethyl ether. Subsequently, CN 1724503A discloses a method for synthesizing acetic acid through liquid-phase carbonylation of CH ₃ Br/CO on a Rh-KI-PPh3 catalyst. The bromine oxidation route disclosed in the above patents can avoid the high-energy synthesis gas route and realize the unconventional activation of methane. The intermediate products CH ₃ Br and CO obtained by this technology provide a variety of options for the synthesis of downstream chemicals, such as the synthesis of acetic acid, dimethyl ether and olefins. Therefore, this is a new methane activation process with short flow and flexible operation.

It has been reported in the literature that methane and simple halogen (Cl ₂ or Br ₂ ) can be dissolved at 250°C under the action of solid superacid (20% NbOF ₃ /Al ₂ O ₃ ) or supported noble metal (0.5% Pt/Al ₂ O ₃ ) catalyst. The following can be converted to monohalomethanes with high selectivity (GA Olah, Acc. Chem. Res., 1987, 20, 422-428). Degirmenci et al. reported that under the action of solid superacid (ZrO ₂ -SO ₄ ^2- /SBA-15) catalyst, methane and Br ₂ could achieve 69% methane conversion and 99% bromomethane selectivity at a reaction temperature of 340°C (V. Degirmenci, A. Yilmaz, D. Uner, Catal. Today, 2009, 142, 30-33). Li et al. reported a MoO ₂ (H ₂ O) ₂ /Zn-MCM-48 catalyst that can activate methane by bromination reaction below 250 °C. The main products are methanol and dimethyl ether, and also produce Methyl bromide and a small amount of CO ₂ (F.B3.Li, GQYuan, Angew.Chem.Int.Ed., 2006, 45, 6541-6544). CN 1640864 discloses a kind of Ru used in methane bromination oxidation reaction /SiO ₂ catalyst, it is reported that the methane conversion rate of this catalytic system can reach 19.1% when the reaction temperature is 530°C, and the selectivity of CH ₃ Br is as high as 90%. A RuNiBaLaO/SiO ₂ catalyst is disclosed in CN 1724503 and CN 101041609. Under the action of the catalyst, the conversion rate of methane reaches 70% when the reaction temperature is 660°C, the overall selectivity of the main products CH ₃ Br and CO is 89%, and the molar ratio of the two is close. But the patent does not provide the stability test results on the catalyst. CN 101992111 discloses a FePO ₄ /SiO ₂ catalyst. Under the action of the catalyst, the conversion rate of methane reaches 50% when the reaction temperature is 570°C, the overall selectivity of the main products CH ₃ Br and CO is 95%, and the molar ratio is close. It is reported in the literature that carbon deposition occurs in FePO ₄ /SiO ₂ catalysts after a period of reaction, and the activity decreases (RHLin, YJDing, LFGong, WDDong, WMChen, Y.Lu, Cat.Today, 2011, 164, 34-39). It is also reported in the literature that Rh/SiO ₂ catalysts are applied to methane bromination oxidation reaction (Z.Liu, L.Huang, WSLi, F.Yang, CTAu and XPZhou, J.Mol.Catal.A: Chem., 2007, 273, 14- 20). The catalyst has a higher loading of Rh and a higher reaction temperature (660°C). Liu et al. synthesized Rh/SiO ₂ catalyst by sol-gel method and investigated its catalytic performance for methane bromination oxidation reaction. Even though the catalyst can obtain close to 40% methane conversion and 90% CH ₃ Br selectivity at the reaction temperature of 660°C, However, the precious metal Rh is obviously lost after reacting for nearly 700 hours (Z. Liu, WSLi, XP Zhou, J. Nat. Gas. Chem., 2010, 19, 522-529).

Contents of the invention

The object of the present invention is to provide an iron-phosphorus-based catalyst for preparing methyl bromide and CO by methane bromination oxidation. the

Another object of the present invention is to provide a method for preparing the above-mentioned catalyst and a method for preparing methyl bromide and CO with high activity and high selectivity by using the catalyst as raw materials with methane, oxygen and HBr aqueous solution. the

In order to realize the purpose of the present invention, the feature that the present invention provides catalyst is:

The active component is one or more of FePO ₄ , Fe ₂ P ₂ O ₇ or α-Fe ₃ (P ₂ O ₇ ) ₂ ; the weight of the active component is 1.0-60.0% of the weight of the catalyst;

The molar ratio of Fe/Si element in the catalyst is 0.001～1.0;

The molar ratio of P/Si element in the catalyst is 1.0-5.0;

The weight of the active component in the catalyst is 1.0-40.0% of the catalyst weight;

The carrier of the catalyst is mesoporous SBA-15 all-silicon molecular sieve;

The specific surface area of the catalyst carrier is 300-1200m ² /g, and the pore volume is 0.65-1.20m ³ /g.

In the above catalyst of the present invention, the weight of the preferred active component is 1.0-40.0% of the weight of the catalyst; the Fe/Si element molar ratio in the preferred catalyst is 0.004-0.6; the P/Si element in the preferred catalyst The molar ratio is 1.5-4.5; the specific surface area of the preferred catalyst is 300-1200m ² /g, and the pore volume is 0.70-1.10m ³ /g.

The preparation of the catalyst of the present invention takes iron salt, phosphoric acid and ethyl orthosilicate as the precursor, and the three-block polymer P123 [(EO) ₂₀ (PO) ₇₀ (EO) ₂₀ ] as the template, and adopts the hydrothermal method to ""One pot cooking" method, the active component (FePO ₄ , Fe ₂ P ₂ O ₇ or α-Fe ₃ (P ₂ O ₇ ) ₂ ) is introduced into the carrier in situ, and then washed, filtered, dried, roasted and formed .

The concrete preparation method of catalyst is as follows:

(1) Mix the tri-block polymer P123(EO) ₂₀ (PO) ₇₀ (EO) ₂₀ , H ₃ PO ₄ and deionized water in a stoichiometric ratio, and stir at 30-90°C for 1-10 hours to obtain solution A . Stir the measured ratio of iron salt, tetraethyl orthosilicate and deionized water at room temperature for 0.5-5 hours to obtain solution B. Under vigorous stirring, solution B was added to solution A, and stirring was continued for 12-48 hours to obtain emulsion C. Transfer the emulsion C to a hydrothermal synthesis tank and crystallize at a temperature of 60-120° C. for 12-48 hours. Then filter the precipitated slurry prepared in the hydrothermal kettle, wash it with deionized water, dry the filter cake at 60°C, and finally bake it in a muffle furnace at 400-800°C for 2-12 hours. The solid powder obtained by calcining is compressed into tablets to obtain the catalyst particles.

The weight ratio of phosphoric acid aqueous solution (H ₃ PO ₄ mass proportion is 85%) and triblock polymer P123(EO) ₂₀ (PO) ₇₀ (EO) ₂₀ in the above solution A is 1.0～10.0; in solution B, Fe/Si The element molar ratio is 0.001-1.0.

The molar ratio of the added deionized water to ethyl orthosilicate [(C ₂ H ₅ O) ₄ Si] is 50:1˜250:1.

(2) Mix the measured ratio of iron salt, triblock polymer P123(EO) ₂₀ (PO) ₇₀ (EO) ₂₀ , H ₃ PO ₄ and deionized water, and stir in a water bath at 30-90°C for 10- Solution D was obtained in 48 hours. A certain amount of ethyl orthosilicate was added into deionized water and stirred at room temperature for 0.5-24 hours to obtain solution E. Under vigorous stirring, solution D was added to solution E, and stirring was continued for 12-48 hours to obtain emulsion F. Transfer the emulsion F to a hydrothermal synthesis tank and crystallize at a temperature of 90-120° C. for 12-48 hours. Then filter the precipitated slurry prepared in the hydrothermal kettle, wash it with deionized water, dry the filter cake at 60°C, and finally bake it in a muffle furnace at 400-800°C for 2-12 hours. The solid powder obtained by roasting is compressed into tablets to obtain the catalyst.

The weight ratio of phosphoric acid aqueous solution (H ₃ PO ₄ mass proportion is 85%) and triblock polymer P123(EO) ₂₀ (PO) ₇₀ (EO) ₂₀ in the above solution D is 1.0～10.0, P/Fe element molar ratio 2.0-1300.0; the ratio of iron salt in solution D to orthosilicate ethyl ester [(C ₂ H ₅ O) ₄ Si] in solution E is 0.001-1.0 according to the molar ratio of Fe/Si element.

The molar ratio of the added deionized water to ethyl orthosilicate [(C ₂ H ₅ O) ₄ Si] is 50:1˜250:1.

The catalyst of the present invention is used in the reaction of methane bromide oxidation to prepare methyl bromide and CO, the reaction temperature range is 400-800°C, the molar ratio of CH ₄ /HBr is 0.5-2.0, the molar ratio of CH ₄ /O ₂ is 0.5-10, HBr The feed rate of aqueous solution is 1.0-10.0mL/h.

Catalyst of the present invention is characterized in that:

1) Excellent structural stability under high temperature hydrothermal conditions;

2) The active component (FePO ₄ , Fe ₂ P ₂ O ₇ or α-Fe ₃ (P ₂ O ₇ ) ₂ ) has a strong binding force with the carrier SBA-15 molecular sieve, and the loss of the active component is small during the methane bromination oxidation reaction ;

3) Good stability and excellent carbon deposition resistance in methane bromination oxidation reaction. the

Detailed ways

Further describe technical characterictic of the present invention by embodiment below, but these embodiments can not limit the present invention. the

Example 1:

Mix 16.0g triblock polymer P123(EO) ₂₀ (PO) ₇₀ (EO) ₂₀ , 28.06g phosphoric acid aqueous solution (phosphoric acid mass specific gravity is 85%) and 562g deionized water, and mechanically stir in a water bath at 35°C Solution A was obtained in 2 hours. 2.89g of ferric nitrate nonahydrate [Fe(NO ₃ ) ₃ .9H ₂ O], 32.8mL of ethyl orthosilicate and 40mL of deionized water were magnetically stirred at room temperature for 0.5 hours to obtain solution B. Under vigorous mechanical stirring at 35°C, solution B was added to solution A, and stirring was continued for 20 hours to obtain emulsion C. Emulsion C was transferred to a hydrothermal synthesis kettle for crystallization at 90° C. for 24 hours. After filtering the slurry containing the precipitate obtained in the hydrothermal kettle and washing with deionized water, the filter cake was dried at 60°C, and finally roasted at 600°C for 4 hours in a muffle furnace to obtain a solid sample (inductively coupled plasma In the composition of the bulk (ICP) test sample, the P/Si molar ratio is 1.65, the Fe/Si molar ratio is 0.048, the specific surface area of the nitrogen physical adsorption test sample is 764m ² /g, and the pore volume is 0.99m ³ /g). The prepared samples were pressed into tablets and 20-40 mesh particles were sieved and loaded into a fixed-bed quartz reactor for evaluation. The reaction products were analyzed by gas chromatography. The reaction conditions are: catalyst loading 2.0g, methane feed 10mL/min, O ₂ feed 5mL/min, HBr/H ₂ O (HBr mass proportion 40%) feed 3mL/h, reaction temperature 590°C, normal pressure. The reaction results were: the conversion rate of methane was 47%, the selectivity of monobromomethane was 40.9%, the selectivity of dibromomethane was 8.2%, the selectivity of CO was 49.7%, and the selectivity of _CO2 was 1.2%.

The conversion ratio and product selectivity of methane are calculated according to the following method:

Methane conversion rate = (moles of converted methane) ÷ (moles of methane entering the reactor) × 100%

Methyl bromide selectivity = (moles of methyl bromide generated) ÷ (moles of methane converted) × 100%

Dibromomethane selectivity = (moles of methylene bromide generated) ÷ (moles of converted methane) × 100%

CO _x selectivity = (moles of CO _x produced) ÷ (moles of methane converted) x 100%

Example 2:

Mix 16.0 g of triblock polymer P123, 28.06 g of phosphoric acid aqueous solution (85% by mass of phosphoric acid) and 556 g of deionized water, and mechanically stir in a water bath at 35° C. for 2 hours to obtain solution A. 6.51 g of ferric chloride [FeCl ₃ .6H ₂ O], 32.8 mL of ethyl orthosilicate and 40 mL of deionized water were magnetically stirred at room temperature for 0.5 hours to obtain solution B. Under vigorous mechanical stirring at 35°C, solution B was added to solution A, and stirring was continued for 20 hours to obtain emulsion C. The emulsion C was transferred to a hydrothermal synthesis kettle for crystallization at 100° C. for 24 hours. After filtering the slurry containing the precipitate prepared in the hydrothermal kettle and washing with deionized water, the filter cake was dried at 80°C, and finally roasted at 600°C for 4 hours in a muffle furnace to obtain a solid sample (inductively coupled plasma In the body (ICP) test sample composition, the P/Si molar ratio is 1.63, the Fe/Si molar ratio is 0.16, the specific surface area of the nitrogen physical adsorption test sample is 660m ² /g, and the pore volume is 0.83m ³ /g). The prepared samples were pressed into tablets and 20-40 mesh particles were sieved and loaded into a fixed-bed quartz reactor for evaluation. The reaction products were analyzed by gas chromatography. The reaction conditions are: catalyst loading 1.0g, methane feed 10mL/min, O ₂ feed 5mL/min, HBr/H ₂ O (HBr mass proportion 40%) feed 3mL/h, reaction temperature 570°C, normal pressure. The reaction results are: the conversion rate of methane is 44.6%, the selectivity of bromomethane is 33.3%, the selectivity of dibromomethane is 15.8%, the selectivity of CO is _50.2 %, and the selectivity of CO is 0.7%.

Example 3:

Mix 16.0 g of triblock polymer P123, 41.16 g of phosphoric acid aqueous solution (85% by mass of phosphoric acid) and 562 g of deionized water, and mechanically stir in a water bath at 35° C. for 2 hours to obtain solution A. 3.82g of ferrous sulfate [FeSO ₄ .7H ₂ O], 32.8mL of ethyl orthosilicate and 40mL of deionized water were magnetically stirred at room temperature for 0.5 hours to obtain solution B. Under vigorous mechanical stirring at 35°C, solution B was added to solution A, and stirring was continued for 20 hours to obtain emulsion C. The emulsion C was transferred to a hydrothermal synthesis kettle for crystallization at 110° C. for 24 hours. After filtering the slurry containing the precipitate obtained in the hydrothermal kettle and washing with deionized water, the filter cake was dried at 60°C, and finally roasted at 600°C for 4 hours in a muffle furnace to obtain a solid sample (inductively coupled plasma In the body (ICP) test sample composition, the P/Si molar ratio is 2.42, the Fe/Si molar ratio is 0.093, the specific surface area of the nitrogen physical adsorption test sample is 769m ² /g, and the pore volume is 1.014m ³ /g). The prepared samples were pressed into tablets and 20-40 mesh particles were sieved and loaded into a fixed-bed quartz reactor for evaluation. The reaction products were analyzed by gas chromatography. The reaction conditions are: catalyst loading 1.0g, methane feed 25mL/min, O ₂ feed 5mL/min, HBr/H ₂ O (HBr mass proportion 40%) feed 8mL/h, reaction temperature 610°C, normal pressure. The reaction results were: the conversion rate of methane was 22.8%, the selectivity of monobromomethane was 69.8%, the selectivity of dibromomethane was 11.3%, the selectivity of CO was 16.9%, and the selectivity of _CO2 was 2.0%.

Example 4:

Mix 16.0 g of triblock polymer P123, 84.19 g of phosphoric acid aqueous solution (85% by mass of phosphoric acid) and 562 g of deionized water, and mechanically stir in a water bath at 35° C. for 2 hours to obtain solution A. 0.289g of ferric nitrate nonahydrate [Fe(NO ₃ ) ₃ .9H ₂ O], 32.8mL of tetraethylorthosilicate and 40mL of deionized water were magnetically stirred at room temperature for 0.5 hours to obtain solution B. Under vigorous mechanical stirring at 35°C, solution B was added to solution A, and stirring was continued for 20 hours to obtain emulsion C. The emulsion C was transferred to a hydrothermal synthesis kettle for crystallization at 120° C. for 24 hours. After filtering the slurry containing the precipitate obtained in the hydrothermal kettle and washing with deionized water, the filter cake was dried at 60°C, and finally roasted at 600°C for 4 hours in a muffle furnace to obtain a solid sample (inductively coupled plasma In the body (ICP) test sample composition, the P/Si molar ratio is 4.95, the Fe/Si molar ratio is 0.0047, the specific surface area of the nitrogen physical adsorption test sample is 546m ² /g, and the pore volume is 0.67m ³ /g). The prepared samples were pressed into tablets and 20-40 mesh particles were sieved and loaded into a fixed-bed quartz reactor for evaluation. The reaction products were analyzed by gas chromatography. The reaction conditions are: catalyst loading 1.0g, methane feed 10mL/min, O ₂ feed 5mL/min, HBr/H ₂ O (HBr mass proportion 40%) feed 10mL/h, reaction temperature 650°C, normal pressure. The reaction results were: the conversion rate of methane was 43.2%, the selectivity of monobromomethane was 61.4%, the selectivity of dibromomethane was 5.2%, the selectivity of CO was 31.9%, and the selectivity of _CO2 was 1.5%.

Embodiment 5:

4.24g ferrous acetate [Fe(CH ₃ COO) ₂ ], 16.0g triblock polymer P123, 28.06g phosphoric acid aqueous solution (phosphoric acid mass specific gravity is 85%) and 562g deionized water were mixed in metering ratio, and mixed at 60 °C in a water bath and stirred for 16 hours to obtain solution D. 32.8 g of ethyl orthosilicate was added into 40 mL of deionized water and magnetically stirred at room temperature for 2 hours to obtain solution E. Under vigorous mechanical stirring, solution D was added to solution E, and stirring was continued for 24 hours to obtain emulsion F. The emulsion F was transferred to a hydrothermal synthesis kettle for crystallization at 90° C. for 24 hours. Then filter the precipitate-containing slurry prepared in the hydrothermal kettle, wash with deionized water, dry the filter cake at 60° C., and finally bake it in a muffle furnace at 600° C. for 4 hours. Roasting gained solid powder obtains described catalyst (inductively coupled plasma (ICP) test sample composition after tabletting, P/Si mol ratio is 1.65, and Fe/Si mol ratio is 0.17, and nitrogen physisorption test sample specific surface area is 700m ² /g, the pore volume is 0.89m ³ /g). The reaction conditions are: catalyst loading 2.0g, methane feed 10mL/min, O ₂ feed 5mL/min, HBr/H ₂ O (HBr mass proportion 40%) feed 4mL/h, reaction temperature 580°C, normal pressure. The reaction results are: the conversion rate of methane is 43.8%, the selectivity of monobromomethane is 49.8%, the selectivity of dibromomethane is 11.0%, the selectivity of CO is 36.9%, and the selectivity of CO is _2.3 %.

Embodiment 6:

52.08g iron nitrate [Fe(NO ₃ ) ₃ .9H ₂ O], 16.0g triblock polymer P123, 41.16g phosphoric acid aqueous solution (phosphoric acid mass specific gravity is 85%) and 560g deionized water were mixed in the metered ratio, and Stir in a water bath at 80°C for 16 hours to obtain solution D. 32.8 g of ethyl orthosilicate was added into 40 mL of deionized water and magnetically stirred at room temperature for 12 hours to obtain solution E. Under vigorous mechanical stirring, solution D was added to solution E, and stirring was continued for 24 hours to obtain emulsion F. The emulsion F was transferred to a hydrothermal synthesis kettle for crystallization at 100° C. for 24 hours. Then filter the precipitate-containing slurry prepared in the hydrothermal kettle, wash with deionized water, dry the filter cake at 60° C., and finally bake it in a muffle furnace at 600° C. for 4 hours. Roasting gained solid powder obtains described catalyst (inductively coupled plasma (ICP) test sample composition after tabletting, P/Si mol ratio is 2.40, and Fe/Si mol ratio is 0.95, and nitrogen physisorption test sample specific surface area is 802m ² /g, the pore volume is 0.92m ³ /g). The reaction conditions are: catalyst loading 1.0g, methane feed 15mL/min, O ₂ feed 5mL/min, HBr/H ₂ O (HBr mass proportion 40%) feed 3mL/h, reaction temperature 600°C, normal pressure. The reaction results are: the conversion rate of methane is 36.5%, the selectivity of bromomethane is 50.8%, the selectivity of dibromomethane is 10.3%, the selectivity of CO is 37.9%, and the selectivity of CO is _1.0 %.

Embodiment 7:

6.51g ferric nitrate [Fe(NO ₃ ) ₃ .9H ₂ O], 16.0g triblock polymer P123, 41.16g phosphoric acid aqueous solution (phosphoric acid mass specific gravity is 85%) and 560g deionized water were mixed in the metered ratio, and Stir in a water bath at 80°C for 16 hours to obtain solution D. 32.8 g of ethyl orthosilicate was added into 40 mL of deionized water and magnetically stirred at room temperature for 12 hours to obtain solution E. Under vigorous mechanical stirring, solution D was added to solution E, and stirring was continued for 24 hours to obtain emulsion F. The emulsion F was transferred to a hydrothermal synthesis kettle for crystallization at 100° C. for 24 hours. Then filter the precipitate-containing slurry prepared in the hydrothermal kettle, wash with deionized water, dry the filter cake at 60° C., and finally bake it in a muffle furnace at 400° C. for 12 hours. Roasting gained solid powder obtains described catalyst (inductively coupled plasma (ICP) test sample composition after tabletting, P/Si mol ratio is 2.37, and Fe/Si mol ratio is 0.095, and nitrogen physisorption test sample specific surface area is 855m ² /g, the pore volume is 0.82m ³ /g). The reaction conditions are: catalyst loading 1.0g, methane feed 15mL/min, O ₂ feed 5mL/min, HBr/H ₂ O (HBr mass proportion 40%) feed 3mL/h, reaction temperature 600°C, normal pressure. The reaction results were: the conversion rate of methane was 37.8%, the selectivity of monobromomethane was 48.8%, the selectivity of dibromomethane was 9.0%, the selectivity of CO was 40.9%, and the selectivity of _CO2 was 1.3%.

Embodiment 8:

Mix 16.0 g of triblock polymer P123, 41.16 g of phosphoric acid aqueous solution (85% by mass of phosphoric acid) and 562 g of deionized water, and mechanically stir in a water bath at 35° C. for 2 hours to obtain solution A. 3.82g of ferrous sulfate [FeSO ₄ .7H ₂ O], 32.8mL of ethyl orthosilicate and 40mL of deionized water were magnetically stirred at room temperature for 0.5 hours to obtain solution B. Under vigorous mechanical stirring at 35°C, solution B was added to solution A, and stirring was continued for 20 hours to obtain emulsion C. The emulsion C was transferred to a hydrothermal synthesis kettle for crystallization at 110° C. for 24 hours. Then filter the slurry containing the precipitate prepared in the hydrothermal kettle, wash with deionized water, dry the filter cake at 60°C, and finally bake it at 500°C for 10 hours in a muffle furnace to obtain a solid sample (inductively coupled plasma In the body (ICP) test sample composition, the P/Si molar ratio is 2.45, the Fe/Si molar ratio is 0.091, the specific surface area of the nitrogen physical adsorption test sample is 705m ² /g, and the pore volume is 1.0m ³ /g). The prepared samples were pressed into tablets and 20-40 mesh particles were sieved and loaded into a fixed-bed quartz reactor for evaluation. The reaction products were analyzed by gas chromatography. The reaction conditions are: catalyst loading 1.0g, methane feed 25mL/min, O ₂ feed 5mL/min, HBr/H ₂ O (HBr mass proportion 40%) feed 6mL/h, reaction temperature 630°C, normal pressure. The reaction results are: the conversion rate of methane is 21.3%, the selectivity of bromomethane is 49.8%, the selectivity of dibromomethane is 6.3%, the selectivity of CO is 40.4%, and the selectivity of _CO is 3.5%.

Embodiment 9:

Mix 16.0 g of triblock polymer P123, 28.06 g of phosphoric acid aqueous solution (85% by mass of phosphoric acid) and 556 g of deionized water, and mechanically stir in a water bath at 35° C. for 2 hours to obtain solution A. 6.51 g of ferric chloride [FeCl ₃ .6H ₂ O], 32.8 mL of ethyl orthosilicate and 40 mL of deionized water were magnetically stirred at room temperature for 0.5 hours to obtain solution B. Under vigorous mechanical stirring at 35°C, solution B was added to solution A, and stirring was continued for 20 hours to obtain emulsion C. The emulsion C was transferred to a hydrothermal synthesis kettle for crystallization at 100° C. for 24 hours. After filtering the slurry containing the precipitate obtained in the hydrothermal kettle and washing with deionized water, the filter cake was dried at 80°C, and finally roasted at 800°C for 2 hours in a muffle furnace to obtain a solid sample (inductively coupled plasma In the body (ICP) test sample composition, the P/Si molar ratio is 1.62, the Fe/Si molar ratio is 0.15, the specific surface area of the nitrogen physical adsorption test sample is 529m ² /g, and the pore volume is 0.78m ³ /g). The prepared samples were pressed into tablets and 20-40 mesh particles were sieved and loaded into a fixed-bed quartz reactor for evaluation. The reaction products were analyzed by gas chromatography. The reaction conditions are: catalyst loading 1.0g, methane feed 10mL/min, O ₂ feed 5mL/min, HBr/H ₂ O (HBr mass proportion 40%) feed 5mL/h, reaction temperature 600°C, normal pressure. The reaction results were: the conversion rate of methane was 47.6%, the selectivity of monobromomethane was 43.0%, the selectivity of dibromomethane was 10.6%, the selectivity of CO was 45.4%, and the selectivity of _CO2 was 1.0%.

Claims (9)

1. one kind is used for the Fe-P-O catalyst that bromine oxidation of methane prepares Celfume and CO, and this catalyst is made up of active component and carrier, wherein:

Active component is FePO ₄, Fe ₂P ₂O ₇Or α-Fe ₃(P ₂O ₇) ₂In one or more; The weight of active component is 1.0～60.0% of catalyst weight;

Fe/Si element mol ratio is 0.001～1.0 in the catalyst;

P/Si element mol ratio is 1.0～5.0 in the catalyst;

Carrier is the total silicon molecular sieve SBA-15;

The specific area of catalyst is 100～1500m ²/ g, pore volume are 0.65～1.20m ³/ g.

2. catalyst according to claim 1, wherein, the weight of said active component is 1.0～40.0% of catalyst weight.

3. catalyst according to claim 1, wherein, Fe/Si element mol ratio is 0.004～0.6 in the said catalyst.

4. catalyst according to claim 1, wherein, P/Si element mol ratio is 1.5～4.5 in the said catalyst.

5. catalyst according to claim 1, wherein, the specific area of said catalyst is 300～1200m ²/ g, pore volume are 0.70～1.10m ³/ g.

6. method for preparing the said catalyst of claim 1, its key step is:

Catalyst is a presoma with molysite, phosphate aqueous solution and ethyl orthosilicate, with triblock polymer [(EO) ₂₀(PO) ₇₀(EO) ₂₀] be template, adopt hydro-thermal method, with active component (FePO ₄, Fe ₂P ₂O ₇Or α-Fe ₃(P ₂O ₇) ₂) original position introducing carrier, form through washing, filtration, drying, roasting, moulding again; Wherein the synthetic crystallization temperature of hydro-thermal is 90-120 ℃, and crystallization time is 12-48 hour; Sintering temperature is 400-800 ℃, and roasting time is 2-12 hour.

7. preparation method according to claim 6, said molysite is one or more in ferric nitrate, iron chloride, frerrous chloride, ferric sulfate, ferrous sulfate, ferric acetate, ferrous acetate, ferric oxalate and the ferrous oxalate.

8. preparation method according to claim 6, said H ₃PO ₄Quality proportion is 85% phosphate aqueous solution and triblock polymer (EO) ₂₀(PO) ₇₀(EO) ₂₀Weight ratio be 1.0～10.0.

9. the said catalyst of claim 1 prepares the application among Celfume and the CO at bromine oxidation of methane, and its reaction temperature interval is 400～800 ℃, CH ₄/ O ₂Mol ratio is 0.5～10, and HBr aqueous solution inlet amount is 1.0～10.0ml/h.