HUP9904003A3 - Heterogeneous bimetallic palladium-gold catalyst for vinyl acetate production and process for manufacturing thereof - Google Patents

Heterogeneous bimetallic palladium-gold catalyst for vinyl acetate production and process for manufacturing thereof

Info

Publication number
HUP9904003A3
HUP9904003A3 HU9904003A HUP9904003A HUP9904003A3 HU P9904003 A3 HUP9904003 A3 HU P9904003A3 HU 9904003 A HU9904003 A HU 9904003A HU P9904003 A HUP9904003 A HU P9904003A HU P9904003 A3 HUP9904003 A3 HU P9904003A3
Authority
HU
Hungary
Prior art keywords
manufacturing
vinyl acetate
gold catalyst
acetate production
bimetallic palladium
Prior art date
Application number
HU9904003A
Other languages
English (en)
Hungarian (hu)
Original Assignee
Celanese Int Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Celanese Int Corp filed Critical Celanese Int Corp
Publication of HUP9904003A1 publication Critical patent/HUP9904003A1/hu
Publication of HUP9904003A3 publication Critical patent/HUP9904003A3/hu

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/0201—Impregnation
    • B01J37/0207—Pretreatment of the support
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/48—Silver or gold
    • B01J23/52—Gold
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/56—Platinum group metals
    • B01J23/58—Platinum group metals with alkali- or alkaline earth metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/66—Silver or gold
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/0201—Impregnation
    • B01J37/0205—Impregnation in several steps
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C67/00—Preparation of carboxylic acid esters
    • C07C67/04—Preparation of carboxylic acid esters by reacting carboxylic acids or symmetrical anhydrides onto unsaturated carbon-to-carbon bonds
    • C07C67/05—Preparation of carboxylic acid esters by reacting carboxylic acids or symmetrical anhydrides onto unsaturated carbon-to-carbon bonds with oxidation
    • C07C67/055—Preparation of carboxylic acid esters by reacting carboxylic acids or symmetrical anhydrides onto unsaturated carbon-to-carbon bonds with oxidation in the presence of platinum group metals or their compounds

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
  • Catalysts (AREA)
HU9904003A 1996-05-24 1997-05-15 Heterogeneous bimetallic palladium-gold catalyst for vinyl acetate production and process for manufacturing thereof HUP9904003A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US08/655,571 US5700753A (en) 1996-05-24 1996-05-24 Heterogeneous bimetallic palladium-gold catalyst for vinyl acetate production
PCT/US1997/008491 WO1997044130A1 (en) 1996-05-24 1997-05-15 Heterogeneous bimetallic palladium-gold catalyst for vinyl acetate production

Publications (2)

Publication Number Publication Date
HUP9904003A1 HUP9904003A1 (hu) 2000-03-28
HUP9904003A3 true HUP9904003A3 (en) 2000-09-28

Family

ID=24629432

Family Applications (1)

Application Number Title Priority Date Filing Date
HU9904003A HUP9904003A3 (en) 1996-05-24 1997-05-15 Heterogeneous bimetallic palladium-gold catalyst for vinyl acetate production and process for manufacturing thereof

Country Status (28)

Country Link
US (1) US5700753A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
EP (1) EP0906151B1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
JP (1) JP4043520B2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
CN (1) CN1093001C (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
AR (2) AR007116A1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
AT (1) ATE203187T1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
AU (1) AU713368B2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
BR (1) BR9709033A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
CA (1) CA2254912C (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
CZ (1) CZ297144B6 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
DE (1) DE69705720T2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
DK (1) DK0906151T3 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
ES (1) ES2159137T3 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
HU (1) HUP9904003A3 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
ID (1) ID16953A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
IN (1) IN191380B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
MY (1) MY114044A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
NO (1) NO316363B1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
NZ (1) NZ332917A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
PL (1) PL189150B1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
RU (1) RU2182516C2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
SA (1) SA97180048B1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
TR (1) TR199802415T2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
TW (1) TW448074B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
UA (1) UA61073C2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
WO (1) WO1997044130A1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
YU (1) YU49149B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
ZA (1) ZA973748B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)

Families Citing this family (40)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6034030A (en) * 1994-02-22 2000-03-07 Celanese International Corporation Vinyl acetate catalyst preparation method
DE4443701C1 (de) * 1994-12-08 1996-08-29 Degussa Schalenkatalysator, Verfahren zu seiner Herstellung und seine Verwendung
US5968869A (en) * 1997-06-03 1999-10-19 Celanese International Corporation Vinyl acetate catalyst comprising palladium and gold deposited on a copper containing carrier
US5948724A (en) * 1997-10-28 1999-09-07 Celanese International Corporation Vinyl acetate catalyst comprising metallic palladium and gold and cupric acetate
KR20010040654A (ko) * 1998-02-05 2001-05-15 스티븐 아이. 밀러 Ｐｄ-Ａｕ 비닐 아세테이트 모노머 촉매의 노화 방지
US6017847A (en) * 1998-06-02 2000-01-25 Celanese International Corporation Vinyl acetate catalyst prepared with potassium aurate and comprising metallic palladium and gold on a carrier precoated with copper
ID26891A (id) 1998-06-02 2001-02-15 Celanese Internasional Corp Katalis vinil asetat yang terdiri dari palladium logam dan emas yang dibuat dengan potasium aurat
US6015769A (en) * 1998-06-02 2000-01-18 Celanese International Corporation Vinyl acetate catalyst comprising metallic palladium, gold and copper supported on a carrier and prepared with potassium aurate
JP2000070718A (ja) 1998-06-17 2000-03-07 Nippon Shokubai Co Ltd ベンジルエステルの製造方法
DE19914066A1 (de) * 1999-03-27 2000-10-05 Celanese Chem Europe Gmbh Katalysatoren für die Gasphasenoxidation von Ethylen und Essigsäure zu Vinylacetat, Verfahren zu ihrer Herstellung und ihre Verwendung
US6821923B1 (en) * 1999-04-08 2004-11-23 Dow Global Technologies Inc. Method of preparing a catalyst containing gold and titanium
EP1185495B1 (en) 1999-04-14 2005-06-15 Showa Denko K K Catalyst for production of acetic acid or acetic acid and ethyl acetate, process for its production and process for production of acetic acid or acetic acid and ethyl acetate using it
US6303537B1 (en) 1999-11-17 2001-10-16 Celanese International Corporation Vinyl acetate catalyst comprising metallic palladium and gold and prepared utilizing sonication
US6509292B1 (en) 2001-03-30 2003-01-21 Sud-Chemie Inc. Process for selective hydrogenation of acetylene in an ethylene purification process
US6936568B2 (en) * 2002-06-12 2005-08-30 Sud-Chemie Inc. Selective hydrogenation catalyst
FR2842125B1 (fr) * 2002-07-09 2006-03-31 Sicat Methode de preparation par impregnation biphasique de nouveaux catalyseurs pour catalyse heterogene, et utilisation desdits catalyseurs
US7655021B2 (en) * 2003-03-10 2010-02-02 Boston Scientific Scimed, Inc. Dilator with expandable member
CN100569364C (zh) * 2003-12-19 2009-12-16 国际人造丝公司 催化剂用层状载体材料
TW200539941A (en) * 2003-12-19 2005-12-16 Celanese Int Corp Methods of making alkenyl alkanoates
US7518014B2 (en) * 2004-12-20 2009-04-14 Celanese International Corp. Modified support materials for catalysts
US7507495B2 (en) * 2004-12-22 2009-03-24 Brookhaven Science Associates, Llc Hydrogen absorption induced metal deposition on palladium and palladium-alloy particles
JP4261502B2 (ja) * 2005-03-14 2009-04-30 富士通マイクロエレクトロニクス株式会社 検証支援装置、検証支援方法、検証支援プログラム、および記録媒体
US8227369B2 (en) * 2005-05-25 2012-07-24 Celanese International Corp. Layered composition and processes for preparing and using the composition
US7704919B2 (en) * 2005-08-01 2010-04-27 Brookhaven Science Associates, Llc Electrocatalysts having gold monolayers on platinum nanoparticle cores, and uses thereof
KR100917495B1 (ko) * 2006-11-27 2009-09-16 나노스텔라 인코포레이티드 팔라듐-금을 포함하는 엔진 배기가스 촉매
US7534738B2 (en) * 2006-11-27 2009-05-19 Nanostellar, Inc. Engine exhaust catalysts containing palladium-gold
US8258070B2 (en) * 2006-11-27 2012-09-04 WGCH Technology Limited Engine exhaust catalysts containing palladium-gold
US7709414B2 (en) * 2006-11-27 2010-05-04 Nanostellar, Inc. Engine exhaust catalysts containing palladium-gold
US7811968B2 (en) * 2007-05-11 2010-10-12 Lyondell Chemical Technology, L.P. Preparation of palladium-gold catalysts
DE102007025315A1 (de) * 2007-05-31 2008-12-11 Süd-Chemie AG Katalysator zur selektiven Hydrierung acetylenischer Kohlenwasserstoffe und Verfahren zu seiner Herstellung
DE102007025362A1 (de) 2007-05-31 2008-12-11 Süd-Chemie AG Dotierter Pd/Au-Schalenkatalysator, Verfahren zu dessen Herstellung sowie dessen Verwendung
DE102007025356A1 (de) * 2007-05-31 2009-01-08 Süd-Chemie AG Verfahren zur Herstellung eines Schalenkatalysators und Schalenkatalysator
DE102007025223A1 (de) 2007-05-31 2008-12-04 Süd-Chemie AG Zirkoniumoxid-dotierter VAM-Schalenkatalysator, Verfahren zu dessen Herstellung sowie dessen Verwendung
DE102007025358A1 (de) * 2007-05-31 2009-01-08 Süd-Chemie AG Verfahren zur Herstellung eines mit Pd und/oder Au beladenen Schalenkatalysators
DE102007025442B4 (de) 2007-05-31 2023-03-02 Clariant International Ltd. Verwendung einer Vorrichtung zur Herstellung eines Schalenkatalysators und Schalenkatalysator
DE102007025443A1 (de) 2007-05-31 2008-12-04 Süd-Chemie AG Pd/Au-Schalenkatalysator enthaltend HfO2, Verfahren zu dessen Herstellung sowie dessen Verwendung
DE102008059341A1 (de) 2008-11-30 2010-06-10 Süd-Chemie AG Katalysatorträger, Verfahren zu seiner Herstellung sowie Verwendung
US8071504B2 (en) * 2008-12-19 2011-12-06 Caterpillar Inc. Exhaust system having a gold-platinum group metal catalyst
GB201110850D0 (en) 2011-03-04 2011-08-10 Johnson Matthey Plc Catalyst and mehtod of preparation
WO2016143490A1 (ja) * 2015-03-09 2016-09-15 国立研究開発法人産業技術総合研究所 金ヒドロキソ陰イオン錯体溶液

Family Cites Families (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1185604B (de) * 1962-02-03 1965-01-21 Bayer Ag Verfahren zur Herstellung von Vinylacetat
DE1252662B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) * 1965-06-25
CH534005A (de) * 1968-02-01 1973-02-28 Bayer Ag Verfahren zur Herstellung eines Palladium und Gold enthaltenden Katalysators
GB1333449A (en) * 1970-11-20 1973-10-10 Hoechst Ag Process for the oxacylation of olefins in the gaseous phase
US3939199A (en) * 1971-01-06 1976-02-17 Hoechst Aktiengesellschaft Oxacylation of olefins in the gaseous phase
JPS514118A (en) * 1974-06-27 1976-01-14 Kuraray Co Sakusanbiniruno seizohoho
US4133962A (en) * 1975-02-14 1979-01-09 Hoechst Aktiengesellschaft Process for the preparation of carboxylic acid alkenyl esters
US4048096A (en) * 1976-04-12 1977-09-13 E. I. Du Pont De Nemours And Company Surface impregnated catalyst
US4089096A (en) * 1976-08-13 1978-05-16 John Graham Michael Method of making school ring top
FR2523149A1 (fr) * 1982-03-15 1983-09-16 Catalyse Soc Prod Francais Nouveau catalyseur supporte palladium-or, sa preparation et son utilisation dans les reactions d'hydrogenation selective d'hydrocarbures diolefiniques et/ou acetyleniques
DE3803900A1 (de) * 1988-02-09 1989-08-17 Hoechst Ag Verfahren zur herstellung von vinylacetat
US4933204A (en) * 1988-09-23 1990-06-12 Rockwell International Corporation Method of producing a gold film
US5179057A (en) * 1991-05-06 1993-01-12 Union Carbide Chemicals & Plastics Technology Corporation Catalysts for alkenyl alkanoate production
US5185308A (en) * 1991-05-06 1993-02-09 Bp Chemicals Limited Catalysts and processes for the manufacture of vinyl acetate
DE4120492A1 (de) * 1991-06-21 1992-12-24 Hoechst Ag Verfahren zur herstellung von vinylacetat
US5194417A (en) * 1991-12-05 1993-03-16 Quantum Chemical Corporation Pretreatment of palladium-gold catalysts useful in vinyl acetate synthesis
US5314858A (en) * 1992-10-14 1994-05-24 Hoechst Celanese Corporation Vinyl acetate catalyst preparation method
DE4239876C1 (de) * 1992-11-27 1994-07-28 Degussa Verfahren zur gleichmäßigen und reproduzierbaren Schalenimprägnierung von als Schüttgut vorliegenden Festbett-Katalysatorträgern und Vorrichtung zur Durchführung des Verfahrens
EP0601705B1 (en) * 1992-12-07 1996-11-06 Ford Motor Company Limited Catalysts from organo-noble metal precursors
DE4323980C1 (de) * 1993-07-16 1995-03-30 Hoechst Ag Palladium und Kalium sowie Cadmium, Barium oder Gold enthaltender Schalenkatalysator, Verfahren zu dessen Herstellung sowie dessen Verwendung zur Herstellung von Vinylacetat
CA2135021A1 (en) * 1993-11-19 1995-05-20 David J. Gulliver Process for the preparation of catalysts for use in the production of vinyl acetate
US5466652A (en) * 1994-02-22 1995-11-14 The Standard Oil Co. Process for the preparation of vinyl acetate catalyst

Also Published As

Publication number Publication date
JP2000511105A (ja) 2000-08-29
YU49149B (sh) 2004-03-12
PL330065A1 (en) 1999-04-26
HUP9904003A1 (hu) 2000-03-28
JP4043520B2 (ja) 2008-02-06
YU15897A (sh) 1999-06-15
DE69705720T2 (de) 2002-06-13
ZA973748B (en) 1998-10-30
PL189150B1 (pl) 2005-06-30
NO316363B1 (no) 2004-01-19
US5700753A (en) 1997-12-23
ES2159137T3 (es) 2001-09-16
CA2254912A1 (en) 1997-11-27
AR011995A2 (es) 2000-09-13
AU3072097A (en) 1997-12-09
IN191380B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 2003-11-29
EP0906151B1 (en) 2001-07-18
CN1219893A (zh) 1999-06-16
CN1093001C (zh) 2002-10-23
TR199802415T2 (xx) 1999-02-22
ATE203187T1 (de) 2001-08-15
EP0906151A1 (en) 1999-04-07
ID16953A (id) 1997-11-27
RU2182516C2 (ru) 2002-05-20
SA97180048B1 (ar) 2005-12-21
CA2254912C (en) 2006-02-14
NZ332917A (en) 2000-03-27
NO985446D0 (no) 1998-11-23
CZ382598A3 (cs) 1999-08-11
WO1997044130A1 (en) 1997-11-27
DE69705720D1 (de) 2001-08-23
MY114044A (en) 2002-07-31
DK0906151T3 (da) 2001-09-24
NO985446L (no) 1998-11-23
AR007116A1 (es) 1999-10-13
CZ297144B6 (cs) 2006-09-13
BR9709033A (pt) 1999-08-03
TW448074B (en) 2001-08-01
UA61073C2 (en) 2003-11-17
AU713368B2 (en) 1999-12-02

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