CN1168534C - Prepn of catalyst for tetramethylbenzene isomerization to prepare durene - Google Patents

Abstract

The present invention relates to a preparation method of a catalyst used for synthesizing durene by tetramethylbenzene isomerization, which is mainly characterized in that the catalyst is a liquid-phase non-hydroisomerization catalyst of tetramethylbenzene using Hbeta molecular sieves as active components. The present invention provides a catalyst used for synthesizing durene, which has the advantages of high activity, high selectivity, good stability, low cost and extensive sources of isomerization raw materials. When in use, the catalyst has the characteristics of no need of hydrogen, liquid-phase reaction, long service life and high conversion rate of tetramethylbenzene. The concentration of the durene in products approaches to or even exceeds that of chemical balance constituents.

Description

Tetramethylbenzene isomerization to prepare durol Preparation of catalysts method

The present invention relates to the Preparation of catalysts method of synthetic a kind of petrochemicals, especially relate to a kind of Preparation of catalysts method with the synthetic durol of durene isomerization.

Durol is a kind of important Organic Chemicals, is mainly used in to produce pyromellitic acid dianhydride (being called for short equal acid anhydride PMDA).PMDA is the important source material of synthesis of polyimides polymer.Polyimides is widely used in aerospace industry, atomic energy industry, the mechanotronics with electrical insulation capability, resistance to elevated temperatures, the radiation resistance of excellence.In addition, PMDA still is the important source material of high-quality heat-resisting plasticizer, curing agent and powdery paints delustering agent, and PMDA consumption in this respect is also increasing, and the demand of durol also is multiplied thereupon.

At present the durol manufacture method of bibliographical information has manyly, but that industrialized production method only limits to is following several:

1. from C ₁₀Separate durol in the heavy aromatics

2. pseudocumene alkylation to prepare durol

3. tetramethylbenzene isomerization to prepare durol

For first method, because C ₁₀The extensive use of heavy aromatics comprehensive utilization technique relies on the C of physical separating process merely ₁₀The durol output of heavy aromatics comprehensive utilization technique by-product is subjected to C ₁₀The restriction of heavy aromatics treating capacity, durol content and aromatic hydrocarbons rolling sales situation and being difficult to further improve.And durol is C ₁₀The important source of heavy aromatics comprehensive utilization technique economic benefit.In this case, make full use of C ₁₀The higher isodurene of content in the heavy aromatics, exploitation isomerization volume increase durol new technology becomes a kind of effective way that improves resource utilization and economic benefit.

At present, the C of domestic several big petro-chemical corporations by-product ₁₀Heavy aromatics is not also utilized completely, and after the aromatic device built is gone into operation a large amount of C of by-product again ₁₀Heavy aromatics, thereby China has abundant C ₁₀The heavy aromatics resource, C ₁₀The heavy aromatics comprehensive utilization technique has suitable wide prospect.

The shortcoming of second method is the cost of material height of pseudocumene, and it is limited to originate, and employed activity of such catalysts, selectivity and stability are not very good, equipment corrosion, environmental pollution.

The employed catalyst of the third method is to be active component with modenite or super steady zeolite, and reaction formation is gas-solid or liquid-solid reaction.But exist catalyst activity low, deficiencies such as poor stability.

The objective of the invention is to develop a kind of active high, selectivity is high, good stability, cost are low, and the isomerization raw material sources are extensive, the Preparation of catalysts method of synthetic durol.

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

1. sial is crushed to the 50-200 order for the Hydrogen beta-molecular sieve of 20-100 (H β) by weight.

2. with γ-Al ₂O ₃Be crushed to the 50-200 order.

3. will be crushed to 50-200 purpose H β and γ-Al ₂O ₃Mix by a certain percentage, its ratio is counted H β 30-80%, γ-Al with weight ratio ₂O ₃Be 20-70%.

4. make adhesive with the HNO aqueous solution or the water glass solution of 0.5-2N, stir kneading, and extruded moulding is a φ 1.5-3.0mm bar shaped catalyst.

5. with the φ 1.5-3.0mm bar shaped catalyst oven dry of extruded moulding, drying condition is:

Bake out temperature 90-370 ℃

Time is 1-6 hour.

6. the φ 1.5-3.0mm bar shaped catalyst roasting after will drying, roasting condition is:

Sintering temperature 400-700 ℃, the time is 2-7 hour

7. cooling is the cost catalyst.

Fig. 1 is an isomerization general flow chart of the present invention.

Table 1 is the different Si/Al ratio of the present invention according to used beta-molecular sieve, and different beta-molecular sieve/γ-Al ₂O ₃Weight ratio, five kinds of catalyst of moulding are followed successively by the various technical data of A, B, C, D, E.

Table 2 for the present invention according to the catalyst A of preparing, B, C, D, E, on laboratory's small stationary reaction unit, under non-adjacent hydrogen condition, carry out the situation of durene isomerization experiments.

This catalyst is to be durene liquid phase, the non-hydro isomerizaiton catalyst of active component with the H beta-molecular sieve.

Embodiment 1: with the sial weight ratio is 20 Hydrogen beta-molecular sieve (H β), 50 grams, γ-Al ₂O ₃50 grams fully mix after being crushed to 200 orders, and as binding agent, extruded moulding gets finished catalyst A 500 ℃ of following roastings after the oven dry down at 90 ℃ with rare nitric acid.

Embodiment 2: with the sial weight ratio is 40 Hydrogen beta-molecular sieve (H β), 40 grams, γ-Al ₂O ₃60 grams fully mix after being crushed to 200 orders, and as binding agent, extruded moulding gets finished catalyst B 530 ℃ of following roastings after the oven dry down at 170 ℃ with rare nitric acid.

Embodiment 3: with the sial weight ratio is 50 Hydrogen beta-molecular sieve (H β), 66 grams, γ-Al ₂O ₃34 grams fully mix after being crushed to 200 orders, and as binding agent, extruded moulding gets finished catalyst C 570 ℃ of following roastings after the oven dry down at 250 ℃ with rare nitric acid.

Embodiment 4: with the sial weight ratio is 70 Hydrogen beta-molecular sieve (H β), 75 grams, γ-Al ₂O ₃25 grams fully mix after being crushed to 200 orders, and as binding agent, extruded moulding gets finished catalyst D 570 ℃ of following roastings after the oven dry down at 300 ℃ with rare nitric acid.

Embodiment 5: with the sial weight ratio is 90 Hydrogen beta-molecular sieve (H β), 80 grams, γ-Al ₂O ₃20 grams fully mix after being crushed to 200 orders, and as binding agent, extruded moulding gets finished catalyst E 600 ℃ of following roastings after the oven dry down at 370 ℃ with rare nitric acid.

Embodiment 6-10:

The catalyst A of preparing with the foregoing description 1-5, B, C, D, E carry out the durene isomerization experiments and see table 2 for details on the small stationary bed reaction device under conditions of non-hydrogen, reaction condition is as follows:

Its reaction condition is as follows:

1) tube inner diameter 10mm, catalyst charge weight 20ml;

2) reaction condition: temperature 200-400 ℃;

3) pressure 0.5-3.0Mpa;

4) air speed 0.5-15.0h ^-1

5) raw material is C ₁₀Heavy aromatics or other aromatic hydrocarbons through rectifying, freezing and crystallizing, are isolated the aromatic solvent of the durene content of durol at 30-70%.

By example 1-5 and 6-10 as can be seen:

The prepared catalyst of the present invention possesses following characteristics under the experiment condition that is provided:

1) durol balance delivery rate height, promptly the durol content in the product has surpassed equilibrium composition.

2) durene yield height.Durene content in the product does not lose substantially or increases than the content in the raw material.The objective of the invention is to develop a kind of active high, selectivity is high, good stability, cost are low, and the isomerization raw material sources are extensive, and are with low cost, the Preparation of catalysts method of synthetic durol.

The performance test of catalyst is on the small stationary bed reaction device, carries out under conditions of non-hydrogen, and reaction condition is as follows:

1) charge weight of catalyst is 5-50ml;

2) reaction temperature 200-400 ℃: with 250-350 ℃ is good;

3) pressure is 0.5-3.0Mpa: with 0.5-3.0Mpa is good;

4) volume space velocity (LHSV) 0.5-15.0h ^-1: with 0.8-10.0h ^-1For good.

The isomerization process summary:

A. the reactor of proper catalyst being packed into, and use N ₂Pressure testing is guaranteed not have and is leaked

B. charging, boost, intensification, constant temperature, constant voltage

5) satisfactory raw material is continuously pumped into reactor by measuring pump, isomerization reaction by catalyst layer, takes place in material simultaneously under uniform temperature, pressure, air speed, from material sample analysis after the cooler cooling of reactor discharge.

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

1) catalyst of the present invention in use adopts the non-hydrogen liquid phase reactor, so do not need hydrogen producer, can simplify technology greatly, reduces technical difficulty and to the requirement of equipment and the degree of danger of process units.

2) it is active high: when this catalyst is used for tetramethylbenzene isomerization to prepare and is equipped with durol, when being raw material with durene or 200A aromatic solvent, in the product composition of durol near in addition surpass chemical balance and form, content can be up to 40-45% in total durene of product for durol; Durene yield height can reach more than 98%.

3) good stability: during the tetramethylbenzene isomerization to prepare durol, catalyst of the present invention has stronger anti-coking performance.

4) catalyst of the present invention does not have corrosion to equipment, non-environmental-pollution, and reaction temperature is low, pressure is low.

Table 1

Embodiment	1	2	3	4	5
						The catalyst code name	A	B	C	D	E
Drying after forming temperature ℃	90	170	250	300	370
						Rare concentration of nitric acid %	0.5	0.8	1.0	1.6	2.0
Sintering temperature ℃	500	530	550	570	600
						Beta-molecular sieve Si/Al	20	40	50	70	90
Beta-molecular sieve/γ-Al 2O 3	1.0	1.5	2.0	3.0	4.0

Table 2

Raw material or reactant are formed (weight %)	Raw material	Example 6	Example 7	Example 8	Example 9	Example 10
							The catalyst that uses
		A	B	C	D	E
							Light component	36.72	37.13	37.08	37.68	37.01	38.51
Durol	7.81	17.89	17.63	17.02	17.93	16.34
							Isodurene	28.11	19.92	19.98	19.38	19.62	19.53
Prehnitene	4.04	3.02	2.93	3.02	2.96	3.30
							Heavy component	23.32	22.04	22.38	22.90	22.48	22.32
Reactivity worth
							Durol/durene %		43.82	43.49	43.18	44.26	41.72
Durene yield %		102.18	101.45	98.65	101.38	98.02
							Durol balance delivery rate %		104.83	10362	100.72	103.22	100.43
Prehnitene conversion ratio % partially,		28.65	28.74	30.33	29.77	28.99

[notes]:

Claims (1)

1, a kind of tetramethylbenzene isomerization to prepare durol Preparation of catalysts method is to be durene liquid phase, the non-hydro isomerizaiton catalyst of active component with the H beta-molecular sieve, and its preparation method is as follows:

(1). with the sial weight ratio is that the Hydrogen beta-molecular sieve (H β) of 20-100 is crushed to the 50-200 order;

(2). with γ-Al ₂O ₃Be crushed to the 50-200 order;

(3). will be crushed to 50-200 purpose H β and γ-Al ₂O ₃Mix by a certain percentage, its ratio is H β 30-80% with the weight ratio, γ-Al ₂O ₃Be 20-70%;

(4) make adhesive with the HNO aqueous solution or the water glass solution of 0.5-2N, stir kneading, and extruded moulding is a φ 1.5-3.0mm bar shaped catalyst;

(5). with the φ 1.5-3.0mm bar shaped catalyst oven dry of extruded moulding, drying condition is:

Bake out temperature 90-370 ℃

Time is 1-6 hour;

(6). the φ 1.5-3.0mm bar shaped catalyst roasting after will drying, roasting condition is:

Sintering temperature 400-700 ℃, the time is 2-7 hour;

(7). cooling back the catalyst finished product.

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