CN1102439C - Middle-temp isomerizing catalyst and its preparing process - Google Patents

Abstract

The present invention relates to a moderate-temperature isomerization catalyst, particularly to a catalyst of Pt/H beta modified by the oxides of transitional metal W and/or Zr. The catalyst has the following compositions and range by weight ratio: 0.3 to 0.6 of Pt, 1 to 25 of transition metal oxides and 75 to 99 of H beta, and is prepared by way of mechanical mixing or immersion. The catalyst can obviously improve the isomerization selectivity of light hydrocarbons (such as n-C7) at a moderate temperature of 240 to 280 DEG C, and simultaneously maintain high conversion activity and stability.

Description

Temp isomerizing catalyst and preparation method thereof in a kind of

The invention belongs to a kind of in temp isomerizing catalyst, relate in particular to transition metal W and (or) Pt/H-Beta (Pt/H β) catalyst of Zr oxide modifying.

Acid catalyzed alkane isomerization reaction is subjected to extensively attracting attention as the important reaction that synthetic high-knock rating gasoline adds component.At present, to C ₇A large amount of research, C have been made in following alkane isomerization reaction ₇And the alkane (C of longer carbochain ₇₊) higher and high-octane rating multibranched paraffin (containing quaternary carbon) is less because of lytic activity, application is restricted.So in actual applications, the application that makes isomerization process of cracking reaction is limited in C ₄-C ₆On the hydrocarbon.

The used catalyst of alkane isomerization mainly contains two types, is noble metal catalyst.One class is Pt-chloride/aluminium chloride, and operating temperature is lower, is 120-150 ℃, the reactivity height of this type of catalyst, and selectivity is good, but strict to sulphur in the raw material, water, and needs to replenish the chloride auxiliary agent.Another kind of is middle temperature Pt (or Pd)/molecular sieve catalyst, reaction temperature 260-280 ℃.Studies show that, for the Pt/H beta catalyst, the C in the time of 240 ℃ ₇Conversion ratio is 47.27%, isomerization selectivity 37.05%; After being warming up to 280 ℃, although C ₇Conversion ratio rises to 97.88%, but isomerization selectivity＜5%.J.A.I.Ch.E.1993,39 (4): in 607 1 literary compositions, T.F.Degnan and C.R.Kennedy find, with Pt/Al ₂O ₃After the beta-molecular sieve physical mixed, at middle warm area to n-C ₇Conversion reaction does not have activity substantially.

The object of the present invention is to provide a kind of middle temp isomerizing catalyst with high activity, high isomerization selectivity and better stability.

The present invention at first adopts mechanical mixing or immersion process for preparing Zr-H β or ZrW-H β complex carrier, again precious metals pt is immersed on this complex carrier, because of W and (or) Zr and H β interact, make catalyst in the time of 240-280 ℃ to n-C ₇Conversion reaction has high activity and high isomerization selectivity.

Catalyst of the present invention is formed weight ratio:

Pt 0.3-0.6 transition metal oxide 1-25 H β 75-99

As above said transition metal oxide be W and (or) Zr oxide, wherein ZrO ₂: WO ₃Weight ratio be 4-20: 1.

Catalyst of the present invention is to adopt mechanical mixing or immersion process for preparing, and step is as follows:

(1) uses NH ₃H ₂O titration ZrOCl ₂The precipitation method of solution prepare amorphous ZrO (OH) _x

(2) according to the above ratio with ZrO (OH) _xEven with H β mechanical mixture, 800-825 ℃ of roasting 3h;

(3) product of roasting compression molding sieves out 20-40 purpose particle H ₂PtCl ₆Solution adopts infusion process to make required catalyst.

The present invention compares with existing catalyst, has the following advantages:

1. paraffin hydro activity of conversion height, middle temp isomerizing selectivity height, stability is also better.

2. preparation process is simple, easy operating.

Embodiment 1

Get the ZrOCl of 0.4M ₂Solution drips NH under 35-40 ℃ of intense agitation ₃H ₂O, the PH=10-11 of control solution, after precipitation left standstill aging 4h, filtration, washing, dried overnight obtained amorphous ZrO (OH) _xTake by weighing 0.34g ZrO (OH) respectively _xWith 3g H beta-molecular sieve, mechanical mixture is even, behind 800-825 ℃ of roasting 3h, obtains Zr-H β complex carrier, with the H of 3g complex carrier at 1.2ml ₂PtCl ₆Solution (1g H ₂PtCl ₆6H ₂O/50ml water) dipping 24h in, dried overnight in 500 ℃ of roasting 5h, makes catalyst A, and catalyst is formed weight ratio and is: Pt 0.3, ZrO ₂10, H β 90.

Embodiment 2

ZrO (OH) _xPreparation process with embodiment 1.Take by weighing 3.44gZrO (OH) respectively _xAnd 0.81gH ₂WO ₄, mechanical mixture is even, behind 800-825 ℃ of roasting 3h, obtains the Zr-W catalyst.Take by weighing 3g H beta-molecular sieve and 0.03g Zr-W catalyst again, after mechanical mixture was even, 550 ℃ of roasting 3h obtained ZrW-H β complex carrier.The 3g complex carrier is immersed in the H of 2.4ml ₂PtCl ₆In the solution, all the other preparation process make catalyst B with embodiment 1, and catalyst is formed weight ratio and is: Pt 0.6, ZrO ₂0.8, WO ₃0.2, H β 99.

Embodiment 3

ZrO (OH) _xPreparation process with embodiment 1.Take by weighing 3.44gZrO (OH) respectively _xAnd 0.49gH ₂WO ₄, mechanical mixture is even, behind 800-825 ℃ of roasting 3h, obtains the Zr-W catalyst.Take by weighing 3g H beta-molecular sieve and 0.75g Zr-W catalyst again, all the other preparation process make catalyst C with embodiment 1, and catalyst is formed weight ratio and is: Pt 0.3, ZrO ₂21.74, WO ₃3.26, H β 75.

Embodiment 4

Zr-W Preparation of catalysts process is with embodiment 2.Take by weighing 3g H beta-molecular sieve and 0.15gZr-W catalyst, after mechanical mixture was even, 550 ℃ of roasting 3h obtained ZrW-H β complex carrier.All the other preparation process make catalyst D with embodiment 1, and catalyst is formed weight ratio and is: Pt 0.3, ZrO ₂4, WO ₃1, H β 95.

Embodiment 5

ZrO (OH) _xPreparation process with embodiment 1.Take by weighing 3.44g ZrO (OH) respectively _xWith 0.16g H ₂WO ₄, mechanical mixture is even, behind 825 ℃ of roasting 3h, obtains the Zr-W catalyst.Take by weighing 3g H beta-molecular sieve and 0.3g Zr-W catalyst again, all the other preparation process make catalyst E with embodiment 1, and catalyst is formed weight ratio and is: Pt 0.6, ZrO ₂9.52, WO ₃0.48, H β 90.

The evaluating catalyst that each embodiment makes:

Make raw material with normal heptane, the weight (hourly) space velocity (WHSV) (WHSV) of micro-amounts of liquids pump feed liquor is 2ml/g.h, H ₂: n-C ₇=15: 1 (mol).Elder generation, faces hydrogen and is warming up to 470 ℃ at 250 ℃ of preliminary treatment 1.5h with Ar gas before the reaction, behind the reductase 12 h, and the sample introduction reaction.Product ov-101 capillary chromatographic column on-line analysis, fid detector, sample analysis behind the reaction 1h.

Catalyst	Reaction temperature (℃)	C 7Conversion ratio (%)	Selectivity of product (%)
						Isomerized products	Pyrolysis product	The aromatization product
			A	240	18.32				93.95	5.17	0.88
280	76.89	87.07				9.79	3.14
				B	240			37.16	93.45	5.97	0.57
280	84.2	60.25	37.3			2.45
					C		240	34.16	91.08	8.16	0
280	87.51	69.26	28.22	2.5
						D	240	29.74	93.04	5.84	1.12
280	81.68	75.42	21.91	2.67
					E		240	39.09	95.37	3.85	0.78
280	85.56	69.38	27.8	2.82

Evaluation result shows that good catalyst activity of the present invention (conversion ratio height) and isomerization selectivity are good.

Claims (3)

1. temp isomerizing catalyst in the alkane is characterized in that described catalyst forms ratio of weight and number and be: Pt: transition metal oxide: H β=0.3-0.6: 1-25: 75-99;

Described transition metal oxide is Zr oxide or Zr and W hopcalite.

2. a kind of middle temp isomerizing catalyst as claimed in claim 1 is characterized in that ZrO in the described catalyst ₂: WO ₃Weight ratio be 4-20: 1.

3. Preparation of catalysts method as claimed in claim 1 or 2 is characterized in that step is as follows:

(1) uses NH ₃H ₂O titration ZrOCl ₂The precipitation method of solution prepare amorphous ZrO (OH) _x

(2) according to the above ratio with ZrO (OH) _xEven with H β mechanical mixture, 800-825 ℃ of roasting 3h;

(3) product of roasting compression molding sieves out 20-40 purpose particle H ₂PtCl ₆Solution adopts infusion process to make required catalyst.