Recycling of Methylaluminoxane (MAO) Cocatalyst in Ethylene Polymerization with Supported Metallocene Catalyst

Jae Seung Oh,이분열,박태호 한국화학공학회 2004 Korean Journal of Chemical Engineering Vol.21 No.1

The economy of the metallocene catalyst system in olefin polymerization depends more on the cost of methylaluminoxane (MAO) cocatalyst rather than on the catalyst cost since high ratio of cocatalyst to catalyst is required to have sufficient activity. The conditions to minimize the consumption of MAO have been studied for the ethylene polymerization with supported metallocene catalyst. By introducing the prepolymerization step, in which the supported metallocene catalyst is activated at high MAO concentration before polymerization, the MAO could be recovered after the prepolymerization and recycled repeatedly for the subsequent activation with marginal decrease in activity. No extra MAO was needed during the main polymerization. The addition of small amount of MAO or less expensive alkylaluminum at each recycle step kept the catalyst activity to the initial level. It compensates the MAO losses occurring both by the incomplete decantation of MAO solution and by the reaction with metallocene complex or impurities. As a result, the actual consumption ratio of Al/Zr in moles in commercial applications could be reduced to about 30 without sacrificing the activity. This value is significantly low considering that conventionally an Al/Zr ratio of 1,000 is required for sufficient activity.

Montmorillonite에 담지된 Cp2ZrCl2 촉매를 이용한 에틸렌 중합특성 연구

박융호 ( Yeung Ho Park ),안성현 ( Sung Htun Ahn ),이성호 ( Sung Ho Lee ),최무석 ( Moo Seok Choi ),임준섭 ( Jun Seop Im ),( Rizwan Sheik ),조득희 ( Deug Hee Cho ) 한국공업화학회 2013 공업화학 Vol.24 No.1

Cp2ZrCl2 촉매를 Montmorillonite (MMT) 담체에 각기 다른 3가지 방법[MMT/Cp2ZrCl2, MMT/MAO/Cp2ZrCl2, MMT/ (MAO + Cp2ZrCl2)]을 적용하여 불균일 촉매를 제조하였고, 이를 이용하여 에틸렌 중합 특성을 조사하였다. 유기점토 인 30B-MMT에 담지한 불균일계 촉매가 자연점토인 Na + -MMT에 담지한 촉매보다 높은 담지율을 나타내었고, 에틸렌 중합에서 높은 활성을 보였다. 이는 유기점토의 층간사이에 존재하는 하이드록시기가 MAO 및 촉매와의 화학적 결합 을 유도한다고 할 수 있다. MMT에 직접 메탈로센을 담지하여 에틸렌 중합에 사용할 경우 균일계 촉매에 비해 낮은 활성을 보이지만, MMT를 MAO로 처리해서 만든 MMT/MAO/Cp2ZrCl2 촉매에 MMAO의 조촉매를 사용하여 중합시에 는 높은 활성을 나타내었다. MMT 담지촉매로 제조된 폴리에틸렌은 담지방법에 관계없이 균일계 촉매에 비해 높은 용융점, 분자량, 분자량 분포를 보였으며, 또한 입자형상에 있어 크기가 상당히 증가한 구형의 입자를 나타내었다. 또한 가장 안정적인 담지 반응과 높은 활성을 나타낸 30B-MMT/MAO/Cp2ZrCl2 촉매로 최적의 중합조건을 찾기 위해 공정변수에 따라 에틸렌 중합을 수행하였다. Heterogeneous metallocene catalysts supported on montmorillonite (MMT), [Cp2ZrCl2/MMT, Cp2ZrCl2/MAO/MMT, and Cp2ZrCl2 + MAO/MMT], were prepared with three different methods of immobilization and tested for ethylene polymerization. The heterogeneous catalysts immobilized on organo clay (30B-MMT) showed the higher metal loading and polymerization activity than those immobilized on natural clay (Na + -MMT). These results suggest that the hydroxyl groups of organo clay interlayers react with the MAO and catalyst through the chemical bond. The metallocene catalyst supported directly on MMT showed lower activity for ethylene polymerization compared to the homogeneous systems, while MMT/MAO/Cp2ZrCl2, catalysts treated with MAO before impregnation, showed a higher activity. The polymers obtained from MMT-supported catalysts have higher melting point, molecular weight and molecular weight distributions than those of homogeneous catalysts. The polymer particles with increasing significant size. Ethylene polymerization over 30B-MMT/MAO/Cp2ZrCl2 catalyst was also performed varying the process variables to optimize the process conditions.

Recycling of Methylaluminoxane (MAO) Cocatalyst in Ethylene Polymerization with Supported Metallocene Catalyst

Oh, Jae Seung,Lee, Bun Yeoul,Park, Tai Ho 한국화학공학회 2004 Korean Journal of Chemical Engineering Vol.21 No.1

The economy of the metallocene catalyst system in olefin polymerization depends more on the cost of methylaluminoxane (MAO) cocatalyst rather than on the catalyst cost since high ratio of cocatalyst to catalyst is required to have sufficient activity. The conditions to minimize the consumption of MAO have been studied for the ethylene polymerization with supported metallocene catalyst. By introducing the prelolymerization step, in which the supported metallocene catalyst is activated at high MAO concentration before polymerization, the MAO could be recovered after the prepolymerization and recycled repeatedly for the subsequent activation with marginal decrease in activity. No extra MAO was needed during the main polymerization. The addition of small amount of MAO or less expensive alkylaluminum at each recycle step kept the catalyst activity to the initial level. It compensates the MAO losses occurring both by the incomplete decantation of MAO solution and by the reaction with metallocene complex or impurities. As a result, the actual consumption ratio of Al/Zr in moles in commercial applications could be reduced to about 30 without sacrificing the activity. This value is significantly low considering that conventionally an Al/Zr ratio of 1,000 is required for sufficient activity.

메탈로센촉매를 이용한 폴리에틸렌 합성에 있어서 수소가 촉매활성과 분자량에 미치는 영향

이철우 한밭대학교 에너지청정기술연구소 2002 에너지청정기술논문집 Vol.2 No.1

본 연구에서는 Cp_2ZrCl_2 촉매를 사용하여 에틸렌을 중합하는 반응에 있어서 수소의 부피%가 촉매활성과 폴리에틸렌의 분자량에 미치는 영향을 살펴보았다. 수소의 부피%가 낮을 경우에는 촉매의 활성은 수소가 없는 경우보다 증가하여, 수소의 부피%가 0.8일 때 최대의 활성을 나타내었다. 이러한 경향은 수소의 농도가 증가함에 따라 촉매의 활성이 감소하는 지글러-나타 촉매의 경우와는 다른 것이다. 수소의 부피%가 높은 경우에는 촉매의 활성은 감소하였다. 폴리에틸렌의 분자량은 수소의 영향을 매우 크게 받으므로 소량의 수소로도 분자량의 조절이 가능하다. 따라서 분자량을 조절하기 위해서는 수소의 비율을 매우 세밀히 조절해야 한다. An investigation was made of the effect of the hydrogen volume%(vol%) on ethylene polymerization activity and moleculer weight using the catalyst Cp_2ZrCl_2. It has been observed that activities increase at low H_2 vol%, reaching a maximum at the H_2 vol% of 0.8. This trend is not observed in Zigler-Natta catalyst. A decrease of the catalyst activity was observed at high H_2 vol%. The molecular weights of the polyethylenes were decrease with incresing H_2 vol%. The effect of hydrogen in the molecular weight was larger in the metallocene catalyst than Zigler-Natta catalyst. Therefore it was necessary to control H_2 vol% precisely in order to control moleculer weight using metallocene catalyst.

Preparation of Flexible Terpolymers using Various Metallocene Catalyst/Borate Cocatalyst System and their Epoxidation

( Jung Soo Kim ),( Jun Choi ),( Dong Hyun Kim ) 한국고무학회 2019 엘라스토머 및 콤포지트 Vol.54 No.4

In this study, flexible poly(ethylene-ter-1-hexene-ter-divinylbenzene) was prepared using four types of metallocene catalysts (rac-Et(Ind)₂ZrCl₂, rac-SiMe₂(Ind)₂ZrCl₂, rac-SiMe₂(2-Me-Ind)₂ZrCl₂, (C₅Me₅)TiCl₂[O-2,6-ⁱPr₂(C₆H₃)]) and two types of borate catalysts (trityl tetrakisborate and dimethylanilinium tetrakisborate). The yield, catalytic activity, molecular weight, structure, composition, and thermal properties of the terpolymers prepared using the various catalysts and cocatalyst systems were evaluated. Epoxidation of the terpolymers was successfully performed and this transformation was studied by 1H NMR and FTIR.

rac-Me₂Si(2-p-tolylindenyl)₂ZrCl₂ 촉매를 이용한 에틸렌/1-옥텐의 공중합 특성

안성현,박융호,Ahn, Sung-Hyun,Park, Yeung-Ho 한국공업화학회 2007 공업화학 Vol.18 No.5

새롭게 합성된 $rac-Me_2Si(2-p-tolylindenyl)_2ZrCl_2$ 촉매와 인디닐 리간드에 치환체가 붙어 있지 않는 상용촉매인 $rac-Me_2Si(Ind)_2ZrCl_2$ 촉매들을 조촉매인 methylaluminoxane (MMAO)를 사용하여 에틸렌/1-옥텐 공중합을 실시하였고, 반응물 내 1-옥텐의 농도를 변화시키며 얻어진 공중합체의 특성을 조사하였다. 촉매활성에 있어서 $rac-Me_2Si(2-p-tolylindenyl)_2ZrCl_2$ 촉매를 이용하여 공중합을 실시한 경우 다리구조를 가진 다른 촉매들과 달리 촉매활성이 감소하여 comonomer의 첨가에 따라 활성이 증가하는 comonomer effect는 발견되지 않았다. $^{13}C$ NMR 분석에서 공중합체에 삽입된 1-옥텐의 양은 촉매 리간드에 붙은 치환체에 의존함을 보였으며, 2-p-tolyl 치환체가 붙은 촉매로 얻어진 공중합체에서 1-옥텐 삽입량이 더 높음을 보였다. DSC, GPC 분석에서 반응물 내 1-옥텐의 농도가 증가함에 따라 공중합체의 녹는점, 결정성, 분자량이 모두 감소하였으며 $rac-Me_2Si(Ind)_2ZrCl_2$ 촉매보다 $rac-Me_2Si(2-p-tolylindenyl)_2ZrCl_2$ 촉매의 경우 녹는점, 결정성 및 분자량의 감소폭이 더 크게 나타났다. The copolymerization characteristics of a newly-synthesized catalyst, $rac-Me_2Si(2-p-tolylindenyl)_2ZrCl_2$, and its analogue, $rac-Me_2Si(Ind)_2ZrCl_2$, were examined in the ethylene/1-octene copolymerization while varying the concentration of 1-octene in the reaction mixture. The activity of $rac-Me_2Si(2-p-tolylindenyl)_2ZrCl_2$ catalyst was decreased with increase of comonomer concentration, which is different from the usual comonomer effect of the metallocene catalysts with a bridge structure. The contents of 1-octene in the copolymer from the catalyst with 2-p-tolyl substituent were higher than those from the catalyst without that substituent. The melting point, crystallinity, and molecular weight decreased with comonomer content which was more apparent for $rac-Me_2Si(2-p-tolylindenyl)_2ZrCl_2$ catalyst.

Effect of the physicochemical properties of SiO2 on performance of supported metallocene catalyst

유혁재,고영수 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.7

The effect of the calcination temperature of SiO2 on ethylene polymerization behavior was studied withsupported metallocene catalysts. The concentration of hydroxyl group on the SiO2 surface was measured through FTIR,thermogravimetry, and trimethylaluminium titration method. In addition, physical properties such as particle morphology,surface area, and pore characteristics were analyzed through BET, and SEM. (n-BuMeCp)2ZrCl2 was supportedon the SiO2, which was calcined at different temperatures in the range of 100 and 900 oC. The resultingsupported catalyst was applied to ethylene homopolymerization and ethylene-1-hexene copolymerization at 80 oC and20 bar, showing that the lower calcination temperature resulted in higher activity due to the larger Zr and Al loadings.

High α-olefin의 사슬길이가 삼원공중합에 미치는 영향

김태완 ( Tae Wan Kim ),이준철 ( Jun Chul Lee ),박노형 ( No Hyung Park ),김현기 ( Hyun Ki Kim ),조을룡 ( Ur Ryong Cho ),김동현 ( Dong Hyun Kim ) 한국고무학회 2012 엘라스토머 및 콤포지트 Vol.47 No.4

지르코늄계 메탈로센 촉매/Borate계 공촉매 시스템을 이용하여 poly(ethylene-ter-high α-olefin-terp-methylstyrene)를 합성하였으며 이 때 사용한 high α-olefin인 1-hexene, 1-octene, 1-decene, 1-dodecene의 사슬길이 변화가 삼원공중합체에 미치는 여러 가지 영향을 분석하였다. 13C NMR과 1H NMR을 이용하여 삼원공중합체의 구조 및 조성을 확인하였고 high α-olefin 사슬길이가 촉매활성도, 수율, 분자량 및 분자량분포도 등에 미치는 영향을 살펴보았다. 또한, 사슬 길이 변화에 따른 삼원공중합체의 morphology변화, 결정화도 변화 및 열적 거동을 비교하였다. In this study, we synthesized poly(ethylene-ter-high α-olefin-ter-p-methylstyrene) using Zr metallocene catalyst/borate type cocatalyst system. Various effects of the high α-olefin (1-hexene, 1-octene, 1-decene, and 1-dodecene) were observed. The structure and composition of the terpolymers were characterized using 13C NMR and 1H NMR. Catalytic activity, polymer yield, molecular weight and molecular weight distribution were analyzed according to the chain length of high α-olefin. We determined morphology, crystallinity and thermal properties of the terpolymers.

Carbon Nanotubes as a Ligand in Cp₂ZrCl₂-Based Ethylene Polymerization

Park, Sungjin,Yoon, Seung Woong,Lee, Kyung-Bok,Kim, Dong Jin,Jung, Young Hwan,Do, Youngkyu,Paik, Hyun-jong,Choi, Insung S. WILEY-VCH Verlag 2006 Macromolecular rapid communications Vol.27 No.1

<P>Summary: We report a simple method for tuning catalytic property of a metallocene-based catalyst, Cp<SUB>2</SUB>ZrCl<SUB>2</SUB>, for ethylene polymerization by the direct adsorption of Cp<SUB>2</SUB>ZrCl<SUB>2</SUB> onto multi-walled carbon nanotubes (MWCNTs). The direct interactions between MWCNTs and the Cp rings of Cp<SUB>2</SUB>ZrCl<SUB>2</SUB> controlled the polymerization behaviors, and we could generate polyethylene with an extremely high molecular weight (<TEX>$\overline M _{\rm w}$</TEX> = 1 000 000) at 30 °C and under 1 atm of ethylene gas.</P><P> <img src='wiley_img/10221336-2006-27-1-MARC200500614-gra001.gif' alt='wiley_img/10221336-2006-27-1-MARC200500614-gra001'> Graphic Preparation of Cp<SUB>2</SUB>ZrCl<SUB>2</SUB>-MWCNT. </P>

Isothermal crystallization behavior of metallocene-catalyzed isotactic polypropylene

Park, Deukkil,Kim, Il,Han, Yang-Kyu,Seul, Soo-Deuk,Kim, Bu-Ung,Ha, Chang-Sik Wiley Subscription Services, Inc., A Wiley Company 2005 Journal of applied polymer science Vol.95 No.2

<P>Isothermal crystallization behavior of isotactic polypropylene (iPP) synthesized using metallocene catalyst was investigated in this work. The isotacticity of the polypropylene was characterized by <SUP>13</SUP>C-NMR spectroscopy. It was found that the melting temperature (T<SUB>m</SUB>) of the iPP is 123.51°C and the crystallization temperature (T<SUB>c</SUB>) is 93°C. The iPP synthesized in this work did not show a general increase of T<SUB>m</SUB> with an increase of crystallization temperature T<SUB>c</SUB>, due to the short crystallization time of 20 min and low molecular weight (number average molecular weight = 6,300). The iPP showed a tendency of increasing heat of fusion (ΔH<SUB>f</SUB>) with decreasing crystallization temperature. All the spherulites of iPP samples showed negative birefringence. For the iPP sample crystallized at the highest T<SUB>c</SUB> (= 123°C, just below T<SUB>m</SUB>), the spherulite showed a pronounced Maltese Cross and a continuous sheaf-like texture aligning radially, which suggests that R-lamellaes are dominant in this spherulite. The crystalline structure of the iPP was also investigated by X-ray diffraction. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 231–237, 2005</P>