CN1131107C - Loading type heteropoly acid catalyst used for prepn. of linear alkyl benzene by alkylation of straight chair olefin and benzene - Google Patents

Abstract

A supported heteropolyacid catalyst for C _10-14 linear olefins and benzene alkylation to produce linear alkylbenzene, consisting of a carrier and an active component, characterized in that: the carrier is a large pore size greater than 6.0A Pore carrier, active components are heteropolyacids and their salts, selected from Y, X, M, β, ZSM-12, MCM-41 molecular sieves, activated carbon, Al ₂ O ₃ , SiO ₂ , TiO ₂ , active The components are heteropolyacids and their salts, selected from phosphotungstic acid, silicotungstic acid, phosphomolybdic acid, silicomolybdic acid, germanium tungstic acid and germanium molybdenum acid. The invention has high olefin conversion rate, high LAB selectivity and stable reaction performance.

Description

A Supported Heteropolyacid Catalyst Used in the Alkylation of Linear Olefins and Benzene to Produce Linear Alkylbenzene

The invention relates to a supported heteropolyacid catalyst for the alkylation of _C10-14 long-chain olefins and benzene to produce linear alkylbenzene (LAB). The reaction of C _10-14 long-chain olefins with benzene on the catalyst can be converted into LAB with high conversion rate and high selectivity, and the catalyst has good reaction stability.

LAB is an intermediate for the production of biodegradable and environmentally friendly alkylbenzenesulfonic acid detergents. It is becoming more and more popular because of its high linearity, high biodegradability, good solubility and emulsification, and is rapidly replacing poor biodegradability. Branched-chain alkylbenzenes (DDB). At present, the industrial production of LAB mainly adopts the HF alkylation process, which has the disadvantages of serious equipment corrosion and environmental pollution. For this reason, people are urged to research and develop solid acid catalysts with low corrosion and easy regeneration. Since the beginning of research in the 1960s, great progress has been made in solid acid catalysts for C _10-14 long-chain olefins and benzene alkylation of LAB. The solid acid catalysts studied mainly include molecular sieve catalysts, amorphous silica-alumina, and clay-type catalysts. Catalysts and Supported Heterogeneous Catalysts. As disclosed in USPat 4,301, molecular sieve catalysts such as HZSM-12, L, HZSM-5 and HZSM-38, the conversion rate of olefins is 94%, and the selectivity of LAB is 73%; as disclosed in EP016144, the non-crystalline acidic silicon-alumina catalyst of large pores , the conversion rate of olefins is 50-87%, the selectivity of monoalkylbenzene is 73-84%, the selectivity of LAB is 98-100%, and the selectivity of 2-LAB is 25-46%; Clay impregnated with rare earth metal ions, olefin conversion rate ≥ 98%, LAB selectivity 85%, USPat 5,157,158 uses silicon-aluminum, or magnesium-silicate clay modified with multivalent metal ions, or with H ₂ SO ₄ , HF After acid treatment, the conversion rate of olefins can reach >95%, the selectivity of LAB is 85-92%, the branched alkylbenzene is 4-7%, the heavy alkylbenzene is 2-7%, and the one-way reaction time of the catalyst reaches 300-400 hours.

The purpose of the invention is to provide a high olefin conversion rate, high LAB selectivity, and a novel solid acid catalyst with stable reaction performance for the production of linear alkylbenzene (LAB) by the alkylation reaction of benzene and linear olefins. The one-pass conversion rate of olefins is more than 97%, the LAB selectivity is 90-96%, the 2-LAB selectivity is more than 30%, and the single-pass service life of the catalyst is 200-500 hours.

The invention provides a supported heteropolyacid catalyst for the alkylation of _C10-14 linear olefins and benzene to produce linear alkylbenzene, which consists of a carrier and an active component, and is characterized in that: the carrier has a pore diameter larger than 6.0 Å macroporous carrier, selected from Y, X, M, β, ZSM-12, MCM-41 molecular sieves, activated carbon, Al ₂ O ₃ , SiO ₂ , TiO ₂ , the active components are heteropolyacids and their salts , selected from phosphotungstic acid, silicotungstic acid, phosphomolybdic acid, silicomomolybdic acid, germanium tungstic acid, germanium molybdenum acid.

When the present invention adopts MCM-41 molecular sieve, its silicon-aluminum ratio should be greater than 20.

When the catalyst of the present invention is applied to the alkylation reaction of benzene and _C10-14 linear olefins, a fixed-bed reactor is used. Benzene and C _10-14 linear olefins are mixed feed, benzene: olefins = 1:1-30:1 (molar ratio), and the weight space velocity of the mixed feed is 0.5-30 h ^-1 . The reaction temperature is 100-300°C, and the reaction pressure is 1.0-5.0 MPa.

The preparation process of catalyst of the present invention is carried out according to the following steps:

1. Crush the silica gel to get 40-60 mesh particles, activate with 1-10% dilute nitric acid or hydrochloric acid for 1-10 hours, then wash with deionized water for 4-20 times until the pH value = 7, and dry at 80-120°C , 300 ~ 700 ° C roasting, prepared silica gel carrier.

2. Take a certain amount of silica gel carrier, and dissolve phosphotungstic acid in deionized water to obtain a certain concentration of phosphotungstic acid solution according to the ratio of 0.1 to 1.0g/g carrier, and then immerse the carrier in the phosphotungstic acid solution. Slowly evaporate to dryness at a certain temperature (room temperature to 100°C), dry at 120°C for 1 to 3 hours, and then roast in a muffle furnace at 200 to 500°C for 1 to 24 hours.

3. Activated carbon and _TiO The preparation method of the supported heteropolyacid catalyst as a carrier is the same as that of silica gel.

4. When the molecular sieve is used as the carrier, the molecular sieve carrier is obtained by exchanging and roasting with NH ₄ NO ₃ to form an H type. The loading method is the same as when the silica gel is used as the carrier.

5. When Al ₂ O ₃ is used as a carrier, use non-aqueous solvents, such as acetic acid, acetone, butyl acetate, trichloroacetic acid, etc.

Deactivated catalyst of the present invention can adopt following method regeneration:

To regenerate the deactivated catalyst, wash with benzene and C _10-14 normal alkanes in a ratio of 1:1 to 10:1. The regeneration conditions are as follows: temperature 120-250°C, pressure 1.0-3.5MPa, mixed feed weight space velocity 2.0-20.0h ^-1 , regeneration time 1-20h.

The catalyst preparation method of the invention is simple and has good repeatability. The catalyst has high activity and LAB selectivity, especially high 2-LAB selectivity (30-36%), and good regeneration performance. The regeneration of the catalyst can be carried out in the reactor under the same conditions as the reaction, and the process is simple and the operation is convenient.

Below by example the content of the present invention is given detailed description.

Embodiment 1 Preparation of supported heteropolyacid catalyst A

The silica gel was pulverized to obtain 20-40 mesh particles, activated with 6% dilute nitric acid for 2 hours, and then washed with deionized water for 10 times until the pH value = 7. Baked at 120°C and baked at 700°C for 8h to obtain a silica gel carrier. Dissolve 3g of phosphotungstic acid in 20ml of deionized water, immerse 10g of silica gel carrier in it, let it stand at room temperature for 2h, evaporate to dryness with stirring in a water bath at 80°C, and bake at 300°C for 8h. Prepare the supported heteropolyacid catalyst A.

Embodiment 2 Preparation of supported heteropolyacid catalyst B

The silica gel was pulverized to obtain 20-40 mesh particles, cured with 6% dilute nitric acid for 2 hours, and then washed 10 times with deionized water until the pH value = 7. Dry at 120°C and bake at 700°C for 8 hours to obtain a silica gel carrier. Dissolve 5g of phosphotungstic acid in 20ml of deionized water, soak 10g of silica gel carrier in it, let it stand at room temperature for 2h, evaporate to dryness with stirring in a water bath at 80°C, and bake at 300°C for 8h. Prepare the supported heteropolyacid catalyst B.

Embodiment 3 Preparation of supported heteropolyacid catalyst C

MCM-41 molecular sieve raw powder was pressed into tablets, crushed to obtain 20-40 mesh particles, exchanged 4 times with NH ₄ NO ₃ , washed 4 times with deionized water, dried at 120°C, and sintered at 540°C for 4 hours to obtain HMCM-41 Molecular sieve carrier. Dissolve 3g of phosphotungstic acid in 20ml of deionized water, soak 10g of HMCM-41 molecular sieve carrier in it, let it stand at room temperature for 2h, evaporate to dryness with stirring in a water bath at 80°C, and bake at 300°C for 8h. Prepare the supported heteropolyacid catalyst C.

Example 4 Preparation of LAB by alkylation reaction of benzene with C _10-13 mixed alkenes and 1-C ₁₂ alkenes Experiment 1

Put 2g of Catalyst A into a φ9×300mm stainless steel reactor, activate it at 350°C for 1h under 200ml/min _N2 purge and bring it to room temperature, then pump in analytically pure benzene dehydrated with color-changing silica gel and 5A molecular sieve in advance 20ml, and start to heat up, feed the raw material at a space velocity of WHSV=4h ^-1 at the same time, wait for the temperature to rise to 150°C and start timing, and the reaction starts. The reaction pressure is 3.0MPa, and the raw materials used in the reaction are: benzene/alkene/ene=10/8/1 (molar ratio) when using mixed alkanes and olefins; benzene/ene=25/1 when using 1-dodecene.

The analysis results of the reaction raw materials are shown in Table 1, and the reaction results are shown in Tables 2 and 3.

Table 1 Composition of C _10-13 mixed alkenes

                      Content (wt%)

C ₁₀ ⁰ 19.19

C ₁₀ ^- 1.47

C ₁₁ ⁰ 28.67

C ₁₁ ^- 3.77

C ₁₂ ⁰ 24.19

C ₁₂ ^- 4.08

C ₁₃ ⁰ 13.37

C ₁₃ ^- 2.16

∑C _10-13 ⁰ 85.42

∑C _10-13 ^- 11.48 Table 2 Benzene and 1-C ₁₂ alkene and C _10-13 mixed alkene respectively in Catalyst A

Alkylation reaction results and product composition

                                                                          

Raw materials: Benzene content (wt%) 93.451 39.576

Olefin content (wt%) 6.549 6.238

In the product: Benzene content (wt%) 90.894 36.554

Olefin content (wt%) 0.138 0

Olefin Conversion (%) 98.01 100

LAB selectivity (%) 92.42 93.25

Selectivity of 2-LAB (%) 34.56 30.90

Example 5 Alkylation reaction of benzene and C _10-13 mixed alkanes and olefins to prepare LAB experiment 2

B catalyst 2g is activated and reacted under the same conditions as in Example 6, and the reaction raw material adopts mixed alkenes, and the reaction results are shown in Table 3.

Table 3 Catalyst Benzene/C _10-13 linear olefins alkylation to produce LAB reaction results

Experiment No. 1 2 3

Catalyst A B C

Olefin Conversion (%) 100 99.6 99.8

LAB selectivity (%) 92.4 92.0 93.5

Example 6 Benzene and C _10-13 mixed alkanes and olefins alkylation reaction to prepare LAB experiment 3

C catalyst 2g is activated and reacted under the same conditions as in Example 6, and the reaction raw material adopts mixed alkenes, and the reaction results are shown in Table 3.

Example 7 Benzene and C _10-13 mixed alkanes and olefins alkylation reaction to prepare LAB catalyst regeneration experiment

Using fresh catalyst A, react in the same way as Experiment 1 for 10-48 hours, and then start to enter regeneration solution (benzene and C _10-14 normal alkanes, mixed in a ratio of 1:1-10:1) for washing. The regeneration conditions are temperature 200°C, pressure 3.0MPa, and mixed feed space velocity 4.0h ^-1 . The regeneration time is 2~48h. After regeneration, react at 170°C for 10-48 hours. In this way, reaction and regeneration are carried out alternately. The reaction results are shown in Table 4.

Table 4 Comparison of reaction performance between fresh catalyst and regenerated catalyst

Experiment No. Fresh Catalyst A Regenerated Catalyst A

Olefin Conversion (%) 100 99.6

LAB selectivity (%) 92.4 93.2

Claims (3)

1. one kind is used for C _10-14The carried heteropoly acid catalyst of linear alkene and benzene alkylation system linear alkylbenzene (LAB), be made of carrier and active component, it is characterized in that: carrier is the macropore carrier of aperture greater than 6.0A, is selected from Y, X, M, β, ZSM-12, MCM-41 molecular sieve, active carbon, Al ₂O ₃, SiO ₂, TiO ₂, SiO wherein ₂Aperture＜50 , active component is heteropoly acid and its esters, is selected from phosphotungstic acid, silico-tungstic acid, phosphomolybdic acid, silicomolybdic acid, germanotungstic acid, germanium molybdic acid.

2. according to the described C that is used for of claim 1 _10-14The carried heteropoly acid catalyst of linear alkene and benzene alkylation system linear alkylbenzene (LAB) is characterized in that: the MCM-41 molecular sieve silica alumina ratio that adopts greater than 20, wherein the mass ratio of heteropoly acid and carrier is 0.1～1.0.

3. described C that is used for of claim 1 _10-14The renovation process of the carried heteropoly acid catalyst of linear alkene and benzene alkylation system linear alkylbenzene (LAB) is characterized in that: catalyst adopts the method for solvent elution to regenerate; Solvent is benzene and C _10-14Normal paraffin mixture mixes in 1: 1～10: 1 ratios; Regeneration condition is: 120～250 ℃ of temperature, pressure 1.0～3.5MPa, mixed feeding weight space velocity are 2.0～20.0h ^-1, the recovery time is 1～20h.