CN1059132C - Method for preparing catalyst for synthesis of 1, 2, 4, 5 -tetramethylbenzene - Google Patents

Abstract

The present invention relates to a method for preparing a catalyst for synthesizing durene. An H-ZSM-5 molecular sieve sold in the market is made into the catalyst by pickling, water washing, baking, calcining, impregnating in rare-earth nitrate, baking and calcining. The catalyst has the advantages of high activity, good selectivity and good stability.

Description

Synthetic durol Preparation of catalysts method

The invention belongs to the alkylating Preparation of catalysts method of a kind of petrochemicals, specifically, relate to a kind of Catalysts and its preparation method of synthetic durol.

The synthetic method of durol mainly contains platforming heavy aromatics fractional crystallization direct method of isolation, pseudocumene disproportionation isomerization method and pseudocumene alkylation process.Alkylation process is divided into liquid phase method and vapor phase method.(Jiangsu chemical industry, the second phase, 1981) have reported the method that pseudocumene chloromethanes solution-air is combined to durol, and catalyst is AlCl ₃, shortcoming is the poor selectivity to durol, and equipment corrosion is serious, and environmental pollution is big.In the method for the synthetic durol of the vapor-phase alkylation method that overcomes above-mentioned shortcoming, what have selects Ag-SiO for use ₂-Al ₂O ₃Catalyst, it is catalyst with the ZSM-5 molecular sieve that the employing Mn.H.Y molecular sieve catalyst that has (see the Jiangsu chemical industry, NO 2,1981) also has the people.(seeing " institute of Petroleum's will " V.3, NO3,185,1988).The common drawback of above-mentioned catalyst is to fail to make activity of such catalysts, selectivity and stability to remain on the higher level simultaneously, alkylating primary raw material all is a pseudocumene, it is the cost height not only, and it is limited to originate, and has limited the development and the application of alkylation process.

The objective of the invention is to develop a kind of active high, Preparation of catalysts method selectivity height and good stability, raw material for alkylation wide material sources and synthetic durol with low cost.

Preparation of catalysts method of the present invention is as follows:

1. with HCl or the H of commercially available H-ZSM-5 zeolite molecular sieve with 0.1-1.0N ₂SO ₄Washing, HCl or the H of the most handy 0.4-0.7N ₂SO ₄Washing, consumption are that every kilogram of zeolite molecular sieve consumes 1.2 kilograms of acid, and heating is boiled, and leaves standstill 3 hours;

2. remove acid solution, being washed till with distilled water does not have Cl in the solution ^-Or SO ₄ ^-Ion;

3. with the molecular sieve oven dry of cleaning, 540 ℃ of roastings 3 hours feed a small amount of water vapor when roasting;

4. the zeolite molecular sieve after the roasting floods with rare earth nitrate solution, and its consumption is that every kilogram of zeolite molecular sieve adds 1.2 kilograms of distilled water and 50-200 gram rare earth nitrate solution, and preferably 80-120 restrains rare earth nitrate solution, and heating is boiled, and leaves standstill 3 hours;

5. remove maceration extract, oven dry;

6. roasting, heat up by following speed:

Normal temperature-100 ℃ 8-10 ℃/minute

100-350 ℃ 2-3 ℃/minute

350-540 ℃ 3-5 ℃/minute

Constant temperature is 3 hours under 540 ℃ temperature, stops heating, is product catalyst after the cooling.

The preparation method of described rare earth nitrate solution is: with rare earth oxide (La ₂O ₃Content is no less than 60%, more preferably greater than 70%) be dissolved in the HNO of 40-50% ₃In the solution, can suitably heat during dissolving, get rare earth nitrate solution after insoluble matter is removed after filtration.

Catalyst of the present invention is used for the synthetic durol of alkylation following advantage:

1. active high: this catalyst is used for mixed C ₉During the aromatic hydrocarbons methanol alkylation, not only pseudocumene component in the raw material is had the ability that alkylation generates durol, and to adjacent,, several components of p-methyl-ethylbenzene have the ability of taking off alkyl, and take off further alkylation generation durol of alkyl product.Mixed C ₉Conversion per pass (work as C ₉Aromatic hydrocarbons: during methyl alcohol=4: 1 (weight)), C ₉The conversion per pass of aromatic hydrocarbons can reach about 30%, if the ratio of methyl alcohol increases, conversion ratio also can improve.

2. selectivity height: this catalyst is used for C ₉During the aromatic hydrocarbons methanol alkylation, do not generate basically penta-methyl benzene, mellitene and＞C ₁₁Component, shown very strong shape selective, in the C10 aromatic hydrocarbons that obtains, durol accounts for more than 98%.

3. good stability: at C ₉During alkylating aromatic hydrocarbon, as if the ZSM-5 sieve peg-raking catalyst of using without modification, be tens hours or more time reaction time, because knot carbon, activity of such catalysts can reduce greatly.Catalyst of the present invention has stronger anti-coking performance, is generally reaction time 12-15 days, and the catalyst of inactivation still can recover active by burning lip-deep carbon distribution, has good regenerability.

4. adaptability to raw material is strong: use this catalyst, producing durol can be raw material with pseudocumene not only, and available C ₇, C ₈Aromatic hydrocarbons and mixed C ₉Aromatic hydrocarbons is raw material, and this not only can reduce cost, but also can suit measures to local conditions to develop durol production.

5. use catalyst of the present invention, do not have corrosion with equipment, non-environmental-pollution is not because produce any material that has corrosive material and environment is polluted when carrying out alkylated reaction with this catalyst.

Embodiment 1

With commercially available H-ZSM-5 zeolite molecular sieve is carrier, gets 1 kilogram of carrier, 1.2 kilograms of 0.5NHCl, and in acidproof enamelled vessel, heating is boiled, and leaves standstill then 3 hours, allows it cool off naturally, discards acid solution, with the distilled water washing, detects less than Cl to cleaning solution again ^-The time till.With the oven dry of the carrier after the washing, put into the electric tube furnace roasting, feed a small amount of water vapor during roasting, after furnace temperature rose to 540 ℃, constant temperature 3 hours stopped heating then, stops to feed water vapour simultaneously.After the cooling, take out carrier and add 1.2 kilograms of distilled water again in acid-resistant container, rare earth nitrate solution 100 grams add 1 kilogram of good carrier of roasting in the solution, heating is boiled, leave standstill 3 hours after, remove maceration extract, the oven dry, press the preceding method roasting, the catalyst finished product.

The catalyst that makes like this, by being applicable to that industrial condition estimates, catalyst amount 20ml, reaction condition is: temperature 365-400 ℃, pressure 1.8-2.0MPa, charging air speed 1.0h ^-1(volume), C ₉Aromatic hydrocarbons: methyl alcohol=4: 1 (weight).Evaluation index:

(1) activity: with durol content X (weight %) expression in the oil phase product of reaction generation

(2) selectivity: with two index expressions

S _AlwaysDurol that expression generates and the C that reacts away ₉Aromatic hydrocarbons mol ratio.

S _C10The C that expression generates ₁₀The shared ratio (weight %) of durol finished product in the aromatic hydrocarbons

(3) stability: represent with the time length that is experienced a reaction time, during i.e. reaction beginning, reaction temperature is 365 ℃, carrying out along with reaction, the durol conversion ratio will descend, for keeping certain conversion ratio (reaching 17.0% (weight) with durol content in the product oil is standard), need improve constantly reaction temperature, when reaction temperature reaches 400 ℃, if the content of durol did not reach 17.0% o'clock in the product oil, stop reaction, carry out catalyst regeneration, from the time that reaction begins to experience to stopping, be reaction time, represent that with T the T value is big more, stability is good more.

The evaluation result of above-mentioned catalyst is:

X＝21.5％

S _Always=73.9%

S _c10＝98.4％

T=288 hour

Embodiment 2

H-ZSM-5 molecular sieve with non-modified is a catalyst, with embodiment 1 identical appreciation condition under estimate, the result is as follows:

X＝14.5％

S _Always=26.7%

S _c10＝95.7％

The stability indicator of reaction, if press embodiment 1 specified standard, T=0, because reaction at the beginning, the content of durol does not just reach 17.0% in the product oil, for comparison purpose, has cancelled 17.0% restriction, reaction has been carried out about 100 hours, and durol content drops to below 10% by 16% in the product oil.

Embodiment 3

When the preparation catalyst, in the preprocessing process, if use the H of 0.5N ₂SO ₄Replace 0.5NHCl, other condition is all identical with embodiment 1, and the gained catalyst is also estimated by the condition of embodiment 1, and the result is

X＝20.7％

S _Always=75.1%

S _c10＝98.2％

T=317 hour

From evaluation result, in preparation catalyst preprocessing process, use H ₂SO ₄As if than better slightly with HCl, but when washing, SO ₄ ^-Compare Cl ^-More difficult removing.

Embodiment 4

When pressing embodiment 1 preparation catalyst, if only carry out preliminary treatment, and do not carry out the rare earth nitrate solution dipping, the catalyst that makes is estimated by the condition of embodiment 1, and the gained result is:

X＝17.4％

S _Always=71.2%

S _c10＝97.1％

T=191 hour

With embodiment 1 relatively, active, selectivity is all on the low side, stability indicator then greatly reduces.

Embodiment 5

When pressing embodiment 1 preparation catalyst, carrier does not carry out preliminary treatment, and directly with the nitric acid rare earth dipping, the catalyst that makes is estimated by the condition of embodiment 1, and the result is as follows:

X＝17.3％

S _Always=57.3%

S _c10＝94.3％

T=185 hour

Obviously, when the preparation catalyst, the preliminary treatment of carrier is obligato step.

Embodiment 6

Press embodiment 5 preparation catalyst, when rare earth nitrate solution floods, the concentration of solution is doubled, the evaluating catalyst result who makes is as follows:

X＝17.9％

S _Always=61.3%

S _c10＝91.8％

T=193 hour

It seems,, increase the concentration of rare earth nitrate solution when flooding, can not obviously improve the reactivity worth of catalyst without the preliminary treatment of catalyst.

Embodiment 7

Press embodiment 1 preparation catalyst, just when the carrier preliminary treatment, sintering temperature is lower, is 460 ℃, and the evaluating catalyst result of gained is:

X＝18.5％

S _Always=78.4%

S _c10＝94.6％

T=218 hour

Sintering temperature also is crucial during preliminary treatment, must be more than 460 ℃, and preferably 500-540 ℃.

Embodiment 8

Press embodiment 1 preparation catalyst, if after the rare earth nitrate solution dipping, when carrying out the catalyst roasting, with 5-8 ℃/minute speed, be warmed up to 540 ℃ than faster, constant temperature is 3 hours then, prepared catalyst is estimated by the condition of embodiment 1, and the result is:

X＝19.5％

S _Always=68.4%

S _c10＝97.8％

T=254 hour

It seems that when the preparation catalyst, if heat up not according to regulated procedure, the catalyst reaction performance that makes is also relatively poor.

Claims (3)

1. synthetic durol Preparation of catalysts method is characterized in that:

(1) with commercially available H-ZSM-5 zeolite molecular sieve, with HCl or the H of 0.1-1.0N ₂SO ₄Washing, consumption is: every kilogram of zeolite molecular sieve consumes 1.2 kilograms of acid, and heating is boiled, and leaves standstill 3 hours;

(2) remove acid solution, being washed till with distilled water does not have Cl in the solution ^-Or SO4 ^-

(3) with the molecular sieve oven dry of cleaning, 540 ℃ of following roastings 3 hours feed small amount of steam when roasting;

(4) molecular sieve after the roasting floods with rare earth nitrate solution, and its consumption is that every kilogram of molecular sieve adds 1.2 kilograms distilled water and 50-200 gram rare earth nitrate solution, and heating is boiled, and leaves standstill 3 hours;

(5) remove maceration extract, oven dry;

(6) roasting, heat up by following speed:

Normal temperature-100 ℃ 8-10 ℃/minute

100-350 ℃ 2-3 ℃/minute

350-540 ℃ 3-5 ℃/minute

Constant temperature is 3 hours under 540 ℃ temperature, stops heating, is product catalyst after the cooling.

2. preparation method according to claim 1 is characterized in that described HCl or H ₂SO ₄Concentration be 0.4-0.7N.

3. preparation method according to claim 1 is characterized in that described rare earth nitrate solution addition is the 80-120 gram.