Chap 13 ZieglarNatta Catalyst Spring 2006 ZieglarNatta Catalyst

Spring 2006 Giulio Natta (1903 -1979) Discovered the synthesis of stereoregular polymers in 1954

Spring 2006 Zieglar-Natta Catalyst Monometallic Bimetallic mechanism assumption: equal site reactivity - Monometallic Corsee

Spring 2006 Zieglar-Natta Catalyst Bimetallic Ti. Cl α-Ti. Cl 3 β-Ti. Cl 3 2

Spring 2006 Polyethylene Polymerization A B E D 10/2/2020 C Hanyang Univ.

Spring 2006 Zieglar-Natta Catalyst PP 경우 α-Ti. Cl 3를 β-Ti. Cl 3 보다 많이

Spring 2006 Zieglar-Natta Catalyst General considerations in Rxn Media Selection Homogeneous Polymzn ◎ Bulk

Spring 2006 Zieglar-Natta Catalyst Heterogeneous Polymzn ◎ Suspension Advantages ① Control runaways ② Monomer

Spring 2006 Zieglar-Natta Catalyst ex) 5μ case 0. 003㎝(30μ) case ◎ Emulsion Polymerization: colloidal

Spring 2006 Zieglar-Natta Catalyst Typical Recipe ; Typical Initiator ; aqueous phase soluble ①

Spring 2006 Zieglar-Natta Catalyst Initiator primary attacking centering some of the originally present micelles

Spring 2006 Zieglar-Natta Catalyst 즉 a micelle turned on 1/2 time & turned off

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Chap 13. Zieglar-Natta Catalyst Spring 2006 Zieglar-Natta Catalyst - Z-N 촉매 발명이전에 PP 는 atactic form 만 형성 - 그 후 isotactic PP of extraordinary MW(>106) 이 형성 LDPE = HPPE HDPE Free radical 10 bil lb/yr Use chromium compds. Zieglar-Natta process 를 최근에 적용 barnch 가 적음 - PP의 characteristic condition Al. R 3, Al. HR 2 PP Natta 4 bil lb Condition 50~90℃ pressure 5 atm 이하 Solid catalyst와 함께 넣고 반응후 H 2 O 이나 ROH 로 정지한 후 catalyst 제거하기 위해 세척. MW은 chain transfer agent 에 의해 control 예) CO 2, H 2 O, … 10/2/2020 Hanyang Univ.

Spring 2006 Giulio Natta (1903 -1979) Discovered the synthesis of stereoregular polymers in 1954 Both earned the Nobel Prize in 1963 10/2/2020 Karl Ziegler (1898 -1973) Discovered that a combination of certain transition metal compounds and organometallic compounds polymerize ethylene in 1953 Hanyang Univ.

Spring 2006 Zieglar-Natta Catalyst Monometallic Bimetallic mechanism assumption: equal site reactivity - Monometallic Corsee mechanism 10/2/2020 Hanyang Univ.

Spring 2006 Zieglar-Natta Catalyst Bimetallic Ti. Cl α-Ti. Cl 3 β-Ti. Cl 3 2 vacancy sites => atactic 1 vacancy site => isotactic 10/2/2020 Hanyang Univ.

Spring 2006 Polyethylene Polymerization A B E D 10/2/2020 C Hanyang Univ.

Spring 2006 Zieglar-Natta Catalyst PP 경우 α-Ti. Cl 3를 β-Ti. Cl 3 보다 많이 사용. Efficiency of catalyst , , or Ti. Cl 3 > Ti. Cl 2 > Ti. Cl 4 -Ti. Cl 3 Kinetics the fraction of the sites that have monomer coordinated with them Conc. of growing chain Bimetallic Conc. of catalyst 10/2/2020 Hanyang Univ.

Spring 2006 Zieglar-Natta Catalyst General considerations in Rxn Media Selection Homogeneous Polymzn ◎ Bulk Advantage ① Minimum contamination ② Cheap ③ Chain transfer to solvent Disadvantage ① Dienes – crosslink (cannot make elimination dienes) ② Monomer removal difficult (if monomer toxin, cannot use) ◎ Solution Advantage Disadvantage 10/2/2020 efficiency ① Diene crosslink ② monomer + solvent, removal is difficult ③ chain transfer to solvent hint Mn Hanyang Univ.

Spring 2006 Zieglar-Natta Catalyst Heterogeneous Polymzn ◎ Suspension Advantages ① Control runaways ② Monomer removal is fair easy Disadvantage ① Diene X-link ② Particle coalescence 합체, 연합, 합착 ③ Contamination by solvent 10/2/2020 ⓐ 100℃ Hanyang Univ.

Spring 2006 Zieglar-Natta Catalyst ex) 5μ case 0. 003㎝(30μ) case ◎ Emulsion Polymerization: colloidal dispersion SBR 생산키 위해 40년대 도입. latex 제조 10/2/2020 Advantage ① Excellent control of runaways ② Diene can be polymerized cheaply ③ Monomer removal is easy ④ Much high M. W. ⑤ A stable emulsion exists for ? in paint formulation Disadvantage ①Contamination of product by emulsifier Hanyang Univ.

Spring 2006 Zieglar-Natta Catalyst Typical Recipe ; Typical Initiator ; aqueous phase soluble ① 104 micelles/cm 3 1010 polymer droplets/cm 3 ② 103 radicals/cm 3·sec 10/2/2020 Ferrous persulfate Hanyang Univ.

Spring 2006 Zieglar-Natta Catalyst Initiator primary attacking centering some of the originally present micelles “Smith-Ewart Kinetics” Spontaneous particles initiation & growth Can count MW Rexnt↓, initiator conc. ↓ => ↑ 10/2/2020 Hanyang Univ.

Spring 2006 Zieglar-Natta Catalyst 즉 a micelle turned on 1/2 time & turned off 1/2 time 1/2 means 1/2 off 1/2 on rate of radical generate and capture Surfing to the internet For further details about Zieglar-Natta Vinyl Polymzn Click next homepage. http: //www. pslc. ws/macrog/ziegler. htm 10/2/2020 Hanyang Univ.