CN1076219C - Silicon phosphorus aluminium molecular sieve containing alkaline earth metal and its synthesis - Google Patents

Abstract

A silicon phosphorus aluminum molecular sieve containing alkaline earth metal, its structural formula can be expressed as nR·mMe·( _SixAlyPz ) _O2 , wherein R is a _{triethylamine} template, n is the number _of moles of the template, and n =0.01～0.5; Me is at least one of alkaline earth metals Ca, Sr and Ba, m is its mole number, and m/y=0.01～0.5 (molar ratio); x, y, z are Si, Al, P respectively mole fraction, and meet: x+y+z=1, x=0.01～0.98, y=0.01～0.60, z=0.01～0.60. The synthesis method is to directly prepare by adding soluble salts containing alkaline earth metals to the raw materials for synthesizing molecular sieves. The process is low in cost, suitable for industrial production, and is an excellent catalyst for producing low-carbon olefins by converting methanol (dimethyl ether).

Description

A kind of aluminium silicophosphate molecular sieve of alkaline including earth metal and synthetic

The present invention relates to the molecule sieve.Specifically provide aluminium silicophosphate molecular sieve that contains alkali earth metal and synthetic method thereof that a class has the class chabazite structure, the catalyzed reaction of utilizing this molecular sieve analog to be produced light olefin for raw material by methyl alcohol (dme) as catalyzer is provided again simultaneously.

Aluminium silicophosphate molecular sieve with class chabazite structure claims that again the SAPO-34 molecular sieve is a kind of by SiO ₂, PO ₂ ⁺, AlO ₂ ⁺Microporous crystal Deng three kinds of tetrahedron elements formations.Its anhydrous chemical constitution can be expressed as: mR (Si _xP _yAl _z) O ₂, wherein R is the organic formwork agent that is present in the molecular sieve crystal micropore, m is the mole number of R; X, y, z are respectively the molar fraction of Si, Al, P, and satisfy: x+y+z=1.European patent EP 0103117 discloses a kind of hydrothermal synthesis method of SAPO-34 molecular sieve, and one of its technical characterstic is to have used tetraethyl ammonium hydroxide in the building-up process, Isopropylamine or be template with the mixture of tetraethyl ammonium hydroxide and di-n-propylamine.After this, U.S. Pat 4440871 has reported that again relevant SAPO-34 molecular sieve synthetic improves one's methods, but adopts identical template.Because these template cost an arm and a leg, the source difficulty is difficult in the industrial production and adopts.Present inventors had once proposed two kinds of technology (CN1087292A and CN1096496A) that are suitable for the synthetic SAPO-34 molecular sieve of suitability for industrialized production employing in advance, and promptly adopting triethylamine or diethylamine is the template synthesized silicon-aluminum phosphate molecular sieve.Adopt this technology synthetic SAPO-34 of institute molecular sieve after roasting, activation treatment, to can be used as by methyl alcohol or/and dimethyl ether conversion is the low-carbon alkene catalyst for reaction.But adopt above-mentioned its crystal grain of the technology synthetic SAPO-34 of institute molecular sieve bigger, and the size to crystal grain is also restive, but the inventor provides a kind of method (CN1106715A) of synthetic this molecular sieve of modulation SAPO-34 zeolite crystal size again for this reason, and the double template that this method is formed with tetraethyl ammonium hydroxide and triethylamine synthesizes the SAPO-34 molecular sieve of different grain sizes.

The object of the present invention is to provide phosphate molecule sieve of a class alkaline including earth metal and preparation method thereof.

The phosphate molecule sieve that contains alkaline-earth metal provided by the invention is named as CHT, and its anhydrous structural formula can be expressed as nRmMe (Si _xAl _yP _z) O ₂, wherein R is the triethylamine template, n is the mole number of template, and n=0.01～0.5; Me is a kind of among alkaline-earth metal Ca, Sr, the Ba, and m is its mole number, and m/y=0.01～0.5 (mol ratio); X, y, z are respectively the molar fraction of Si, Al, P, and meet: x+y+z=1, x=0.01～0.98, y=0.01～0.60, z=0.01～0.60.

The synthetic method of preparation CHT molecular sieve of the present invention, the first takes hydrothermal synthesis method directly to prepare; It two is that to adopt triethylamine be template, and other various raw materials also are cheap and easy to get; The silicon source can be silicon ester, silicon sol or active silica, the aluminium source can be aluminum alkoxide or aluminium hydroxide, the phosphorus source can be ortho-phosphoric acid or phosphalugel, and the raw material of alkali earth metals such as Ca, Sr, Ba can adopt their soluble salt, as muriate, vitriol or nitrate etc.; It three is that synthesis condition is grasped easily, can obtain purified product in the gel compositing range of broad He under the crystal condition; It four is that synthetic cost is low, is suitable for industrial production.The feature of above-mentioned preparation process is in the process of synthesis of molecular sieve the alkaline-earth metal soluble salt to be joined the phosphate molecule sieve that directly synthesizes alkaline including earth metal in the raw material of synthesis of molecular sieve.Synthetic primary process is as follows:

(1) according to relational expression nRmMe (Si _xAl _yP _z) O ₂: 10～500H ₂The proportioning raw materials that O determines takes by weighing a certain amount of triethylamine, alkaline earth salt, silicon source, phosphorus source, aluminium source and water.R is triethylamine (N (C in the following formula ₂H ₅) ₃, NEt ₃), its mole number n=0.05～3.0; Me represents alkaline-earth metal, and its adding mole number m is: m/y=0.01～1.0; X, y, z are respectively the molar fraction of silicon, aluminium, phosphorus, and: x+y+z=1, x=0.01～0.98, y=0.01～0.60, z=0.01～0.60.

(2) under agitation above-mentioned various raw materials are mixed according to certain way, make gel;

(3) gel is put in has in the teflon-lined stainless steel autoclave, and seal;

(4) reactor is heated to 150～250 ℃ of constant temperature certain hours, treat that crystallization fully after, with cold water reactor is cooled to room temperature rapidly;

(5) take out reaction product, solid phase prod is separated, through washing, dry air (80～120 ℃), obtain the molecular sieve raw material again with centrifugation or filter type.

The crystalline structure of above-mentioned sintetics is measured with Japanese D/max-rb type X-ray diffractometer of science.Test condition: Cu target, voltage 30～40kV, electric current 40～50mA.

Molecular sieve provided by the invention has very high thermostability, and differential thermal analysis result confirms that the thermostability of its skeleton is higher than 1200 ℃.

Molecular sieve provided by the present invention is the effective catalyst of many organic reactions.When producing the low-carbon alkene catalyst for reaction as it as methyl alcohol or dimethyl ether conversion, the catalytic performance with following excellence: reaction can be carried out under lower temperature, reaction conversion ratio height, the selectivity height of low-carbon alkene in the product.

The operation steps of its Preparation of Catalyst is: institute's synthetic molecular sieve raw material is left in 300～600 ℃ of roastings at air, is removed triethylamine, adopt again suitable forming technique (as adding binding agent) with its moulding, make the beaded catalyst of certain particle size.Preparation of catalysts technology is routinely carried out.

The invention will be further described for example below.

Embodiment one CHT synthetic 1

Take by weighing 130 gram phosphoric acid (H ₃PO ₄85Wt%) be diluted in 150 ml waters solution A; Take by weighing 78 gram pseudobochmite (Al ₂O ₃65Wt%) add in 50 ml waters, stir.Add 100 gram solution A again, stir, obtain sol B; Take by weighing 16 gram calcium acetates and be dissolved in 100 ml waters, add 84 gram silicon sol (SiO again ₂25Wt%), the adding sol B that stirs stirs; Add 180 remaining gram solution A, and mix; Add 51 gram triethylamine and 41 ml waters, stir, make gel, its dress has been encapsulated in the teflon-lined stainless steel autoclave.Be heated to 200 ℃, isothermal reaction is after 120 hours under autogenous pressure, and logical cold water is cooled to room temperature rapidly with it.Then, solid phase prod is filtered out, after washing with water again, toasted 10 hours down, obtain molecular screen primary powder (being numbered CHT-1) at 90 ℃.Sample thief is done the test of X-ray powder diffraction, obtains table 1 column data.The XRD data basically identical of these data and chabazite, promptly sintetics is the molecular sieve with class chabazite structure.Sample thief is made element chemical analysis, obtains its no water body phase composite to be: 0.08NEt ₃: 0.26SiO ₂: Al ₂O ₃: 0.91P ₂O ₅: 0.16CaO, that is: 0.02NEt ₃0.04Ca (Si _0.06Al _0.49P _0.45) O ₂

Table 1

2θ	d()	100×I/Io	2θ	d()	100×I/Io
						9.25	9.56	100	22.55	3.94	8
12.85	6.89	14	23.1	3.85	10
						13.95	6.35	7	25.85	3.45	18
15.9	5.57	37	26.35	3.38	10
						18.92	5.24	11	26.65	3.35	8
18.9	4.70	9	26.8	3.33	7
						19.15	4.64	9	27.55	3.24	8
20.58	4.32	54	28.2	3.16	8
						21.08	4.21	16	29.45	3.03	9
21.3	4.17	16	30.55	2.93	19
						21.95	4.05	8	31.0	2.89	20

Embodiment 2 CHT Synthetic 2s

Take by weighing 31.2 gram dichloride barium and be dissolved in 150 ml waters, add 120 gram silicon sol (SiO again ₂25Wt%), stir, get Sol A; Take by weighing 77.2 gram pseudobochmite (Al ₂O ₃65Wt%) add in 200 ml waters, after stirring, drop into 116 gram phosphoric acid (H again ₃PO ₄85Wt%), after mixing, add 55.6 gram triethylamine and 100 ml waters.After stirring, add Sol A.At room temperature stirred 1 hour, and made gel, its dress has been encapsulated in the teflon-lined stainless steel autoclave, be heated to 200 ℃, isothermal reaction is after 90 hours under autogenous pressure, and logical cold water is cooled to room temperature rapidly with it.Then, solid phase prod is filtered out, after washing with water, toasted 7 hours down at 110 ℃ again, obtain molecular screen primary powder (being numbered CHT-2), sample thief is done the test of X-ray powder diffraction, obtains table 2 column data.The listed data basically identical of these data and table 1 is that sintetics is the molecular sieve with class chabazite structure.Sample thief is made element chemical analysis, gets its no water body phase composite to be: 0.10NEt ₃: 0.57SiO ₂: Al ₂O ₃: 0.83P ₂O ₅: 0.23BaO, that is: 0.02NEt ₃0.05Ba (Si _0.14Al _0.47P _0.39) O ₂

Table 2

2θ	d()	100×I/Io	2θ	d()	100×I/Io
						9.45	9.36	100	21.23	4.18	14
12.83	6.90	13	23.03	3.86	8
						14.00	6.33	6	24.77	3.59	10
15.98	5.54	38	24.98	3.56	13
						16.9	5.24	10	25.83	3.45	17
17.88	4.96	9	27.52	3.24	7
						19.03	4.66	8	29.48	3.25	7
20.1	4.42	10	29.97	2.98	9
						20.55	4.32	55	30.52	2.93	18
21.03	4.22	13	31.02	2.88	18

Embodiment 3 CHT synthetic 3

Take by weighing 70 gram pseudobochmite (Al ₂O ₃65wt%) add in 150 ml waters, after stirring, add 48 gram silicon sol (SiO ₂25wt%), stir, get Sol A; Take by weighing 16 the gram strontium nitrates and 10 the gram calcium chloride be dissolved in 60 ml waters, solution B; Take by weighing 123 gram phosphoric acid (H ₃PO ₄85wt%) be diluted in 150 ml waters, add 70 gram triethylamines.After stirring, add Sol A, solution B successively while stir again.Restock 103 ml waters at room temperature stirred 3 hours, make gel, and its dress has been encapsulated in the teflon-lined stainless steel autoclave.Be heated to 170 ℃, isothermal reaction is after 200 hours under autogenous pressure, and logical cold water is cooled to room temperature rapidly with it.Then, solid phase prod is filtered out, after washing with water again, toasted 10 hours down, obtain table 3 column data at 100 ℃.The listed data basically identical of these data and table 1 and table 2, promptly sintetics is the molecular sieve with class chabazite structure.Sample gets its no water body phase composite through element chemical analysis: 0.13NEt ₃: 0.18SiO ₂: Al ₂O ₃: 0.92P ₂O ₅: 0.13SrO: 0.08CaO, that is: 0.03NEt ₃0.02Ca0.03Sr (Si _0.04Al _0.50P _0.46) O ₂The X-ray powder diffraction feature of typical C HT molecular sieve is by the data representation of table 4, the value that sets in the value of its interplanar distance d such as the table 4.

Table 3

2θ	d()	100×I/Io	2θ	d()	100×I/Io
						9.25	9.29	100	24.6	3.62	9
12.93	6.85	13	25.07	3.55	9
						14.1	6.28	6	25.5	3.49	12
16.08	5.51	40	25.97	3.43	16
						17.1	5.18	10	27.8	3.21	6
19.1	4.65	8	28.9	3.09	5
						20.3	4.37	12	29.62	3.02	9
20.63	4.31	52	30.33	2.95	18
						21.28	4.17	13	30.68	2.91	17
21.48	4.14	13	30.96	2.89	18
						22.08	4.03	6	32.5	2.75	7
22.4	3.97	5	32.5	2.75	7
						23.13	3.85	7

The X-ray powder diffraction feature of table 4 CHT molecular sieve

2 θ d () relative intensities
	9.2～9.6 9.60～9.20 vs 15.9～16.1 5.60～5.50 m 20.4～20.7 4.40～4.30 m～s 25.8～26 3.50～3.40 w～m 30.5～30.7 2.94～2.92 w～m 31.0～31.2 2.90～2.87 w～m

The preparation of embodiment four CHT molecular sieve catalysts

To respectively get a part among the above-mentioned example synthetic molecular screen primary powder CHT-1 of institute, CHT-2 and the CHT-3, under the condition of blowing air,, remove template, be converted into hydrogen type molecular sieve through 350 ℃ 1 hour, 450 ℃ 1 hour, 550 ℃ roastings in 4 hours.To be cooled to room temperature, with its compressing tablet, fragmentation, sieve out the sieve particle of 20～40 order granularities, obtain catalyzer CHT-1, CHT-2 and CHT-3.

Embodiment five CHT molecular sieves are to the catalytic performance in the converting methanol to prepare low carbon olefin reaction

Adopt atmospheric fixed bed reaction unit, reactor material is a silica glass, and catalyzer is prepared CHT-1, CHT-2 and CHT-3 of embodiment four, and its loading amount is 1.28 grams, catalyzer is packed into behind the reactor, purges with nitrogen (60 ml/min) at 500 ℃ earlier to activate in 1 hour.Be cooled to 450 ℃ then, bring methyl alcohol into reactor with nitrogen and carry out the methanol conversion reaction.Methyl alcohol weight space velocity WHSV=2h ^-1, total air speed CHSV=1426h ^-1, reaction pressure is 0.1～0.15MPa, table 5 is all 30 minutes reaction result when having listed reaction.

Table 5

Catalyzer transformation efficiency hydrocarbon product distribution (wt%) is CH (wt%) 4 C 2H 4 C 2H 6 C 3H 6 C 3H 8 C 4H 8 C 4H 10 C 5～C 2-4 -
	CHT-1 100 2.42 49.03 1.37 34.15 3.66 7.38 2.12 0 90.56 CHT-2 100 1.24 41.90 1.34 38.88 8.47 6.17 2.00 0 86.95 CHT-3 100 2.00 42.73 1.24 38.00 7.67 6.18 2.19 0 86.91 SAPO-34 100 1.21 38.17 1.42 36.35 7.56 10.31 4.97 0 84.83

By table 4 as seen, the catalytic performance of CHT molecular sieve obviously is better than SAPO-34, shows that this molecular sieve analog has exploitation to be worth very much, and in addition, the small molecules hydro carbons is transformed this molecular sieve analog and aldol condensation also has katalysis preferably.

Claims (3)

1. A silicon-phosphorus-aluminum molecular sieve of a chabazite-like _structure is characterized in that it contains an alkaline earth metal element, and the structural formula is nR mMe ( _SixAlyPz ) _{O2Representation} , wherein _R is a template, and n is the number of the template Mole number, and n=0.01~0.5; Me is an alkaline earth metal, m is its mole number; x, y, z are the mole fractions of Si, Al, and P respectively, and they meet: x+y+z=1, and the molar ratio m/y =0.01-0.5; template agent is triethylamine; x=0.01-0.98, y=0.01-0.60, z=0.01-0.60. 2. The molecular sieve according to claim 1, characterized in that the alkaline earth metal Me is one or more of Ca, Sr or Ba. 3, a kind of preparation method by the described molecular sieve of claim 1 is characterized in that the soluble salt containing alkaline earth metal is joined in the raw material of synthetic molecular sieve and directly synthesizes the silicon phosphorus aluminum molecular sieve containing alkaline earth metal; The salt of alkaline earth metal is chloride , nitrate or sulfate; proceed as follows: ( ₁ ) Weigh triethylamine, alkaline earth metal salt _, silicon source _{, phosphorus} source _, aluminum source and water; (2) Mix the above-mentioned various raw materials evenly under stirring to make a gel; (3) The gel is placed in a stainless steel autoclave with a polytetrafluoroethylene lining, and sealed; (4) Heat the reactor to 150-250°C, and after the constant temperature crystallization is complete, cool the reactor to room temperature with cold water; (5) Take out the reaction product, separate the solid product by centrifugation or filtration, wash with water, and air-dry at 80-120°C to obtain the molecular sieve raw material; The crystal structure of the above-mentioned synthesized product was determined with a Japanese Rigaku D/max-rb X-ray diffractometer; test conditions: Cu target, voltage 30-40kV, current 40-50mA; The above silicon source is silicate, silica sol or active silica, the aluminum source is aluminum alkoxide or aluminum hydroxide, and the phosphorus source is orthophosphoric acid or aluminum phosphate.