Process for preparing titanium odified supported chromium catalyst and its use

A chromium-based catalyst and catalyst technology, applied in the field of titanium-modified carrier-type chromium-based catalysts, to achieve high melt index and strong hydrogen tuning ability

Active Publication Date: 2006-11-08
SHANGHAI HONGAN CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, titanates, such as isopropyl titanate, cannot simply be in direct contact with untreated carrier silica, because the pore structure of untreated carrier silica contains 10-12% free water, which will interact with titanium. Esters react to produce ineffective TiO 2 lumps instead of ideal TiO 2 The surface layer, so the carrier silica must be heat-treated to remove free moisture before adding the titanium component

Method used

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  • Process for preparing titanium odified supported chromium catalyst and its use
  • Process for preparing titanium odified supported chromium catalyst and its use
  • Process for preparing titanium odified supported chromium catalyst and its use

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0060] This example aims to reveal the importance of the contact reaction method and addition sequence of the three raw materials of carrier silica gel, titanium compound and chromium compound in catalyst preparation, which determine the hydrogen adjustment ability of the final catalyst. This example also demonstrates the influence of the pore volume (PV) of the carrier silica gel and the sodium (Na) content in the silica gel on the performance of the final catalyst.

[0061] Three commercially available carrier silica gels were used in the preparation of the catalyst: silica gel A: pore volume 1.92ml / g, specific surface area 539m 2 / g, sodium content 2000ppm; silica gel B: pore volume 1.97ml / g, specific surface area 509m 2 / g, sodium content 1100ppm; silica gel C: pore volume 1.55ml / g, specific surface area 490m 2 / g, sodium content 1000ppm.

[0062] These carrier silica gels are processed by different methods, and the method includes the following 3 steps:

[0063] (1) im...

Embodiment 2

[0070] This example uses another commercially available carrier silica gel with a pore volume of 1.90ml / g and a specific surface area of ​​510m 2 / g, sodium content 950ppm.

[0071] The carrier silica gel was first impregnated with chromium acetate aqueous solution, and the amount of chromium compound added was based on the chromium content in the final catalyst being 1% by weight. Isopropyl titanate solution in heptane. The addition amount of the titanium compound is different in each preparation example. After distilling off the heptane, the catalysts obtained in each preparation example were activated by calcining at 600° C. according to the method described in Example 1 to obtain final catalysts with different titanium contents. Each catalyst was subjected to polymerization reaction evaluation at 105°C. The test results are listed in Table 2.

[0072] As can be seen from Table 2, as the titanium content in the catalyst increases, the polymer melt index (MI) and the hig...

Embodiment 3

[0075] The purpose of this example is to compare the catalyst of the present invention with currently known commercially available catalysts with better hydrogen adjustment ability, and investigate their hydrogen adjustment ability.

[0076] The "catalyst of the present invention" mentioned in this example was prepared by the method of Example 2 using the carrier silica gel B described in Example 1. That is: first impregnate the carrier silica gel with chromium acetate in isopropanol solution, then dry it at 200° C. according to the method in Example 2, and then impregnate with different amounts of isopropyl titanate heptane solution. Finally, the final catalyst was obtained by calcining and activating at 600°C. Catalysts were evaluated for polymerization at 105°C.

[0077] Produced and sold by W.R Grace under the trademark Magnapore  The commercially available catalyst was also calcined and activated at 600° C., and then evaluated for polymerization under the same conditio...

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Abstract

The present invention relates to a kind of titanium modified and supported chromium catalyst and its preparation process and application. The catalyst features the carrier of silica gel to support titanium compound and chromium compound, titanium content of 1-10 wt%, and chromium content of 0.001-10 wt%. The preparation process includes the following steps: 1. drying at 100-250 deg.c carrier silica gel of pore volume 1.8-2.2 ml / g and specific surface area 400-600 sq m / g; 2. supporting titanium compound on carrier silica gel; 3. supporting chromium compound on carrier silica gel; and 4. calcining at 550-800 deg.c in the air to activate the carrier silica gel with supported titanium and chromium to obtain the catalyst. The catalyst has powerful hydrogen regulating capacity, and is used to producing polymer with high melt index and low shearing response.

Description

technical field [0001] The invention relates to a titanium-modified supported chromium catalyst, its preparation method and application. Background technique [0002] Compared with Ziegler-Natta catalysts or metallocene catalysts, chromium-based catalysts can produce broad molecular weight polyethylene products for blow molding, drum packaging, pipe and other important commercial applications. Therefore, extrusion-grade polyethylene resins are almost exclusively produced using chromium-based catalysts. The disadvantage of chromium-based catalysts is poor hydrogen adjustment ability. In other words, chromium-based catalysts are more likely to produce high molecular weight (low melt index) polymers. Therefore, it is generally desired to increase the hydrogen adjustment ability of the chromium / silica gel catalyst so that it can produce products with higher melt index. The study showed that adding titanium to the chromium catalyst is an effective approach. The molecular weig...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08F4/74C08F210/16
Inventor 谭世治
Owner SHANGHAI HONGAN CHEM
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