vulcan catalytic reaction guide - (106) heterogeneous reaction mechanisms

Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown Activation Reduction In-situ Ex-situ Sulfiding Specializing in Refinery Process Catalyst Performance Evaluation Heat & Mass Balance Analysis Catalyst Remaining Life Determination Catalyst Deactivation Assessment Catalyst Performance Characterization Refining & Gas Processing & Petrochemical Industries Catalysts / Process Technology - Hydrogen Catalysts / Process Technology – Ammonia Catalyst Process Technology - Methanol Catalysts / process Technology – Petrochemicals Specializing in the Development & Commercialization of New Technology in the Refining & Petrochemical Industries

Web Site: www.GBHEnterprises.com

GBH Enterprises, Ltd.

VULCAN SYSTEMS HETEROGENEOUS CATALYST APPLICATIONS Catalytic Reaction Guide: (106) Heterogeneous Reaction Mechanisms

Process Disclaimer

Information contained in this publication or as otherwise supplied to Users is believed to be accurate and correct at time of going to press, and is given in good faith, but it is for the User to satisfy itself of the suitability of the information for its own particular purpose. GBHE gives no warranty as to the fitness of this information for any particular purpose and any implied warranty or condition (statutory or otherwise) is excluded except to the extent that exclusion is prevented by law. GBHE accepts no liability resulting from reliance on this information. Freedom under Patent, Copyright and Designs cannot be assumed.



HETEROGENEOUS REACTION CHEMISTRY CONTENTS 0 HETEROGENEOUS POWDERED CATALYSTS 1 CHOICE OF METAL 2 CHOICE OF SUPPORT 3 MASS TRANSPORT AND REACTOR DESIGN 4 CATALYST DESIGN 5 CATALYST SEPARATION, FILTRATION 6 PROCESS ECONOMICS 6.1 Activated Carbon 6.2 Alumina 6.3 Calcium Carbonate 6.4 Barium Sulfate 6.5 Other Powdered Supports



VULCAN Catalytic Reaction GuideChemistry Reactions

1. Hydrogenation 1-55

1.1 C-C Multiple Bonds 1-71.2 Aromatic Ring Compounds 8-141.3 Carbonyl Compounds 15-251.4 Nitro and Nitroso Compounds 28-351.5 Halonitroaromatics 361.6 Reductive Alkylation's 37 & 381.7 Imines 39-411.8 Nitriles 42-471.9 Oximes 48-491.10 Hydrogenolysis 50-541.11 Other 55

2. Dehydrogenation 56-60

3. Hydroformylation 61& 62

4. Carbonylation 63-68

5. Decarbonylation 69

6. Hydrosilylation 70 & 71

7. Cross Coupling 72-96

7.1 Heck 72-757.2 Suzuki 767.3 Buckwald-Hartwig 77 & 787.4 Organometallics 79-837.5 Sonogashira 84-877.6 Other 88-96

8. Cycloproportion 97

9. Selective Oxidation 98-106

9.1 Alcohols to Carbonyls 98-1029.2 Dihydoxylation of Alkenes 1039.3 Oxygen Insertion Reactions 1049.4 Others 105-106

Catalytic Reaction Guide: (106) Heterogeneous Reaction Mechanisms



0 HETEROGENEOUS POWDERED CATALYSTS

Supported precious metal catalysts are used for a variety of reactions including hydrogenation, dehydrogenation, hydrogenolysis, oxidation, disproportionation and isomerization. Many important organic transformations are completed via catalytic hydrogenation. A large number of these reactions are carried out in the liquid phase, using batch type slurry processes and a supported heterogeneous platinum group metal catalyst. Platinum group metal catalysts will reduce most organic functional groups. The selection of a catalyst or catalyst system for a new catalytic process requires many important technical and economic considerations. The process of selecting a precious metal catalyst can be broken down into components. Key catalyst properties are high activity, high selectivity, high recycle capability and filterability. Important process components include choice of catalytic metal, choice of support, reactor design, heat and mass transport, catalyst design, catalyst separation, and spent catalyst recovery and refining.

1 CHOICE OF METAL

Catalyst performance is determined mainly by the precious metal component. A metal is chosen based both on its ability to complete the desired reaction and its inability to complete an unwanted reaction. Palladium is typically the preferred metal for hydrogenation of acetylenes, olefins, carbonyls in aromatic aldehydes and ketones, aromatic and aliphatic nitro compounds, reductive alkylation, hydrogenolysis and hydrodehalogenation reactions. Platinum is typically the preferred metal for selective hydrogenation of halonitroaromatics and reductive alkylations. Rhodium is used for the hydrogenation of aromatic rings and olefins while ruthenium is used for the hydrogenation of aromatic rings and aliphatic aldehydes and ketones.



2 CHOICE OF SUPPORT

In general, a catalyst support should allow for a high degree of metal dispersion. The choice of support is largely determined by the nature of the reaction system. A support should be stable under reaction and regeneration conditions, and not adversely interact with solvent, reactants or reaction products. Common powdered supports include activated carbon, alumina, silica, silica-alumina, carbon black, TiO2, ZrO2, CaCO3, and BaSO4. The majority of precious metal catalysts are supported on either carbon or alumina. Information on common powdered supports is summarized on .

Figure 1. The Effect of Catalyst Support on Platinum Dispersion

A support can affect catalyst activity, selectivity, recycling, refining, material handling and reproducibility. Critical properties of a support include surface area, pore volume, pore size distribution, particle size, attrition resistance, acidity, basicity, impurity levels, and the ability to promote metal support interactions. Metal dispersion increases with support surface area. The effect of increasing support surface area on metal dispersion for a series of platinum catalysts prepared on activated carbon, silica, alumina, carbon black, and graphite supports is shown in Figure 1.



Support porosity affects metal dispersion and distribution, metal sintering resistance, and intraparticle diffusion of reactants, products and poisons. Smaller support particle size increases catalytic activity but decreases filterability. A support should have desirable mechanical properties, attrition resistance and hardness. An attrition resistant support allows for multiple catalyst recycling and rapid filtration. Support impurities may deactivate the metal and enhance catalyst selectivity. The concentration of precious metal deposited on a support is typically between 1 and 10 weight percent. Practical metal concentration limits are between 0.1 and 20 weight percent for activated carbon, and between 0.1 and 5 weight percent for alumina. Relative catalyst activity will generally increase with decreasing metal concentration at constant metal loading.

3 MASS TRANSPORT AND REACTOR DESIGN

Liquid phase hydrogenations employing heterogeneous catalysts are multiple phase (gas-liquid-solid) systems containing concentration and temperature gradients. In order to obtain a true measure of catalytic performance, heat transfer resistances and mass transfer resistances need to be understood and minimized. Mass transfer effects can alter reaction times, reaction selectivity, and product yields. The intrinsic rate of a chemical reaction can be totally obscured when a reaction is mass transport limited. For reaction to take place in a multi-phase system, the following steps must occur: 1) transport of the gaseous reactant into the liquid phase, 2) transport



Figure 2. Concentration Gradients in Gas/Liquid/Solid Catalytic system

of the dissolved gaseous reactant through the bulk liquid to the surface of a catalyst particle, 3) transport of the dissolved substrate through the liquid to the surface of the catalyst particle, 4) diffusion of the reactants into the pore structure of the catalyst particle, 5) chemisorption of reactants, chemical reaction, desorption of products, and 6) diffusion of the products out of the pore structure of the catalyst particle (Figure 2). Detailed rate expressions have been developed for such systems. Rate of reaction will be affected by different process variables, depending on which step is rate-limiting. A reaction controlled by gas-liquid mass transport, i.e. the rate of mass transport of the gaseous reactant into the liquid, will be influenced mainly by reactor design, hydrogen pressure, and agitation rate. A reaction controlled by liquid-solid mass transport, i.e. the rate of mass transport of either gaseous reactant or substrate from the bulk liquid to the external surface of the catalyst particle, will be influenced mainly by gas or substrate concentration, weight of catalyst in reactor, agitation and catalyst particle size distribution.



A reaction controlled by pore diffusion-chemical reaction, i.e. the rate of reactant diffusion and chemical reaction within the catalyst particle, will be influenced mainly by temperature, reactant concentration, percent metal on the support, number and location of active catalytic sites, catalyst particle size distribution and pore structure. To evaluate and rank catalysts in order of intrinsic catalytic activity, it is necessary to operate under conditions where mass transfer is not rate limiting. A reactor used for liquid phase hydrogenations should provide for good gas-liquid and liquid-solid mass transport, heat transport, and uniformly suspend the solid catalyst.

4 CATALYST DESIGN

The size of the deposited precious metal particulates and their location on the support material affect the properties and performance of a heterogeneous catalyst. Increased metal dispersion and decreased metal particle size generally result in increased catalyst activity. Metal location and metal dispersion can be controlled during catalyst manufacture. Metal particulates can be deposited preferentially at the exterior surface of the support to give what is termed an “eggshell” or “surface-loaded” catalyst. Catalysts with metal particulates evenly dispersed throughout the support structure are referred to as having a “standard” or “uniform” metal distribution (Figure 3).

Figure 3. Schematic of Metal Location



particulates can be deposited preferentially at the exterior surface of the support to give what is termed an “eggshell” or “surface-loaded” catalyst. Catalysts with metal particulates evenly dispersed throughout the support structure are referred to as having a “standard” or “uniform” metal distribution (Figure 3). Catalysts are designed with different metal locations for reactions which take place under different conditions of pressure and temperature. Hydrogenation reactions are generally first order with respect to hydrogen. As such, standard catalysts with increased metal dispersions typically exhibit greater relative activity at high hydrogen pressures. Eggshell catalysts exhibit higher relative activity at low hydrogen pressures. Hydrogenation of large molecules is generally carried out using eggshell catalysts. Variation of metal location can also be used to alter catalyst selectivity. Location of catalytic metal deep into the pore structure of the support may lead to significant reactant pore diffusion limitations. Such catalysts, however, are generally more poison resistant because catalyst poisons are typically of high molecular weight, and unlike smaller reactant molecules, are unable to penetrate into the catalyst pore structure to deactivate the catalytic metal. Deposited metal may be either in a reduced or unreduced form. Unreduced catalysts are readily reduced under the conditions of the catalytic hydrogenation itself, and are often more active than reduced catalysts. Catalysts may be modified with compounds that promote or inhibit certain reactions. Modifiers affect catalytic activity, selectivity and/or life.



5 CATALYST SEPARATION, FILTRATION

A good powdered catalyst should be easy to separate from the reaction mixture and final product. Catalyst filtration time should be minimized to ensure maximum product throughput and production rates. Cycle time advantages gained from a high activity catalyst can be lost if catalyst filtration becomes an extended and time consuming step.

A catalyst should exhibit high attrition resistance to reduce catalyst losses resulting from generation and loss of catalyst “fines”. The generation of “fines” will also decrease the rate of filtration. There is often a trade-off between catalyst performance and the rate of catalyst separation. Catalyst filtration rate and attrition resistance are largely functions of particle size, particle shape, pore volume, pore size distribution, surface area and raw material source.

6 PROCESS ECONOMICS

It is important to consider the economic viability of a catalyst and catalytic process early in the selection process. The economics of using a supported precious metal catalyst depend critically on catalyst turnover number, i.e. the amount of product produced per amount of catalyst used, and on catalytic activity or turnovers per unit time. For supported catalysts it is often convenient to calculate costs in terms of the weight of product produced per weight of catalyst used, or catalyst productivity. Catalyst productivity (P) is defined as:

P = nS/L where n is the number of times a catalyst is used or recycled, S is reaction selectivity as a weight percent (weight of desired product produced per weight of feedstock), and L is catalyst loading as a weight percent (weight of catalyst used per weight of feedstock). The cost of the catalyst per unit weight of product can be determined by dividing the total cost of the catalyst by the catalyst productivity.



Typical catalyst costs include catalyst fabrication, spent catalyst refining or disposal and precious metal charges. In the case of a catalyst returned for refining and reclamation of the precious metal, the total metal charges should include only metal irrecoverably lost during the catalytic process, the refining process, and due to handling. If the maximum allowable catalyst cost per unit weight of product is known, one can back calculate to determine required reaction selectivity and/or the number of catalyst recycles necessary to make a process economically feasible. Most of the commonly used catalyst supports, particularly carbon and alumina, are available in a wide range of particle sizes and surface areas.

6.1 Activated Carbon

Activated carbon powder is used principally as a support for catalysts in liquid phase reactions. As carbon is derived from naturally occurring materials, there are many variations, each type having its own particular physical and chemical properties. The surface areas of different carbons can range from 500 m2g-1 to over 1500 m2g-1. Trace impurities that may be present in certain reaction systems can occasionally poison catalysts. The high absorptive power of carbons used as catalyst supports can enable such impurities to be removed, leading to longer catalyst life and purer products.

6.2 Alumina

Activated alumina powder has a lower surface area than most carbons, usually in the range of 75 m2g-1 to 350 m2g-1. It is a more easily characterized and less absorptive material than carbon. It is also noncombustible. Alumina is used instead of carbon when excessive loss of expensive reactants or products by absorption must be prevented. When more than one reaction is possible, a platinum group metal supported on alumina may prove to be more selective than the same metal supported on carbon.



6.3 Calcium Carbonate

Calcium carbonate is particularly suitable as a support for palladium, especially when a selectively poisoned catalyst is required. The surface area of calcium carbonate is low but it finds application where a support of low absorption or of a basic nature is required, for example to prevent the hydrogenolysis of carbon oxygen bonds.

6.4 Barium Sulfate

Barium sulfate is another low surface area catalyst support. This support is a dense material and requires powerful agitation of the reaction system to assure uniform dispersal of the catalyst.

6.5 Other Powdered Supports

Silica is sometimes used when a support of low absorptive capacity with a neutral, rather than basic or amphoteric character is required. Silica-alumina can be used when an acidic support is needed.

VULCAN Catalytic Reaction GuideChemistry Reactions

1. Hydrogenation 1-55

1.1 C-C Multiple Bonds 1-71.2 Aromatic Ring Compounds 8-141.3 Carbonyl Compounds 15-251.4 Nitro and Nitroso Compounds 28-351.5 Halonitroaromatics 361.6 Reductive Alkylation's 37 & 381.7 Imines 39-411.8 Nitriles 42-471.9 Oximes 48-491.10 Hydrogenolysis 50-541.11 Other 55

2. Dehydrogenation 56-60

3. Hydroformylation 61& 62

4. Carbonylation 63-68

5. Decarbonylation 69

6. Hydrosilylation 70 & 71

7. Cross Coupling 72-96

7.1 Heck 72-757.2 Suzuki 767.3 Buckwald-Hartwig 77 & 787.4 Organometallics 79-837.5 Sonogashira 84-877.6 Other 88-96

8. Cycloproportion 97

9. Selective Oxidation 98-106

9.1 Alcohols to Carbonyls 98-1029.2 Dihydoxylation of Alkenes 1039.3 Oxygen Insertion Reactions 1049.4 Others 105-106

Reactant Product Metal Support Reaction Temp.

Reaction Pressure

Solvents COMMENTS

(deg. C) (BAR)

Pd > Pt > Rh Rh = Ru = Ir

C > Al2O3 = BaSO4 BaSO4 =

CaCO3

5-100 3-10 None or low polarity solvent

Rh, Pt or Ru used for stereoselective application. Pd may cause isomerization

Pd C > Al203 20-100 1-10 None or low polarity solvent

Pd very active under mild conditions.

Pd CaCO3 > C C > BaSO4

5-50 1-3 Low Polarity Solvent

Doped Catalyst (Lindlar) under mild conditions

Pt > Rh > Pd Pd = Ru

C > AlO3 5-100 1-10 Neutral or acidic for Cl, Br Neutral or basic for others

X = OR, OCOR, Cl, Br, NHR, No base with halogens; no acid with

others

Pd > Ru >Pt Al2O3 > C C > CaCO3

5-100 1-3 None or a Polar solvent

Pd most common catalyst.

Ir-40; Rh-93, 100; Ru-100

None 20-80 1-5 Various Least hindered double bond reduced. Asymmetric

hydrogenation with chiral ligands

Pt > Pd > Rh C > Al2O3 50-150 3-10 None or low polarity solvent

Pd may give disproportionation

1.1 C-C Multiple Bonds

VULCAN Catalytic Reaction Guide


Reaction Pressure

Solvents COMMENTS

(deg. C) (BAR)

Rh> Pt Pt = Ru > Pd

C > Al2O3 50-150 3-50 No solvent Rh active under mild conditions.

Pd >> Rh Al203 > C 100-150Ɨ > 150Ŧ

1-50 None or low polarity solvent

Basic promoters enhance activity / selectivity.

Rh > Pd > Ru

C > Al2O3 5-150 1-50 None or low polarity solvent

Rh preferred - no selectivity problems.

Pt >> Ir C >> Al2O3 5-150 1-50 Acidic solvent Acetic acid or alcohol/HCl preferred.

Rh > Ru C > Al2O3 100-150 3-50 Acetic acid Pd most common catalyst.

Rh > Ru > Pt C > Al2O3 50-150 3-10 for Rh > 50 for Ru

Low polarity solvent

X = OH, OR, OCOR, NH2, NHR, Rh preferred - no hydrogenolysis.

Product Reactant

Pt = Rh C >> Al2O3 30-150 3-50 None or alcohol Acetic acid may enhance activity.

1.2 Aromatic Ring Compounds


Product Reactant Metal Support Reaction Temp.

Reaction Pressure

Solvents COMMENTS

(deg. C) (BAR)Ru > Pt C > Al2O3 5-100 1-50 Low polarity

solventFe2+ or Sn2+ salts promote Pt. Water promotes Ru.

Pt C > CaCO3 5-100 1-20 Non-polar or low polarity solvent

Modifiers required, e.g. Base, Fe2+ or Zn2+ salts.

Pd C >> Al2O3 5-100 1-10 Neutral solvent Acid causes loss of OH

Ru > Rh > Pt C >> Al2O3 50-150 1-50 Polar solvent (e.g. water)

Ru requires high pressure.

Rh -40, 92, 93, 100 Ru-42,

100

None 25-110 1-200 Various Asymmetric Hydrogenation possible with chiral ligands. Reduction of the

ketone also possible via hydrosilation.

Pt C >> Al2O3 5-150 1-10 Low polarity solvent

Modifiers required, e.g. Base, Fe2+ or Zn2+ salts.

Pd C >> Al2O3 5-50 1-10 Low polarity solvent

Acid promotes hydrogenolysis of OH

Rh >> Ru C >> Al2O3 5-100 1-50 Low polarity or neutral solvent

Ru requires high temperaturesand pressures.

Pd C > Al2O3 5-100 1-10 Acidic solvent Promoted by strong acids.

Rh/Mo or Rh/Re

Al2O3 150-200 80-100 Ethers Works best with 2o or 3o amides. Poor for 1o amides.

Ru C > Al2O3 200-280 200-300 None or an alcoholic solvent

Promoted by Sn.

1.3 Carbonyl Compounds



Reaction Pressure

Solvents COMMENTS

(deg. C) (BAR)

Pd = Pt > Rh C 50-100 3-50 Low polarity solvent

Bases often inhibit reaction. Prduct amine may poison catalyst.

Reactant Product

Pd C >> Al2O3 5-100 1-10 Low polarity solvent

Acids normally prevent dimer formation.

Pd = Pt C > Al2O3 5-50 1-5 Various Neutral conditions

Pt > Pd = Ir CaCO3 > BaSO4 BaSO4 > Al2O3

5-100 1-5 Various Use N- or S- compounds as moderators

Pt C 50-150 <1-3 Dilute H2SO4 The Benner process.

Pd > Pt > Ru C >> Al2O3 50-100 1-10 Polar or low polarity solvent

In presence of base.

Pd >> Pt C 5-100 1-10 Low polarity solvent

Acetic acid/mineral acid solvent preferred

Pd = Pt C > Al2O3 5-50 1-10 Various Neutral or mildly acidic conditions preferred

Pd > Pt > Rh C 5-100 1-10 Various Mineralacid/acetic acid or mineral acid/alcohol

Pd >>Rh C >> Al2O3 5-100 1-10 Polar or low polarity solvent

Many dissolved salts improve rate.

1.4 Nitro & Nitroso



Reaction Pressure

Solvents COMMENTS

(deg. C) (BAR)Pt >> Rh = Pd C 5-100 1-10 Low polarity

solventX = halogen F >> Cl > Br > I. Stability to hydrogenolysis

1.5 Halonitroaromatics


Metal Support Reaction Temp.

Reaction Pressure

Solvents COMMENTS

Reactant Product (deg. C) (BAR)

Pd = Pt C >> Al2O3 50-150 3-50 Low polarity solvent

Schiff base formulation catalysed by acid.

Pd = Pt C >> Al203 50-150 1-50 None or low polarity solvent

Often add ketone and more catalyst after nitro reduction

1.6 Reductive Alkylations



Reaction Pressure

Solvents COMMENTS

Pt C >> Al2O3 50-150 3-50 Low polarity solvent

Acidic conditions favored.

Product Reactant

Ir-93, Rh-93, 100, Ru-100

None 25-170 1-200 DMF, Ethanol Asymmetric hydrogenation possible with chiral ligands.

Pt C 50-100 3-50 Various Acetic acid or ethanol best.

1.7 Imines



Reaction Pressure

Solvents COMMENTS

(deg. C) (BAR)

Pd = Rh > Pt C > > Al2O3 50-100 1-10 Acidic solvent or additionof excess

ammonia.

Best Solvent is alcohol plus 1-2 equivalents of HCl or H2SO4

Rh C > > Al2O3 5-100 '1-10 Neutral solvent Rh gives good selectivity.

Pd > > Pt C >> Al2O3 5-100 1-10 Neutral solvent Pd gives best selectivity.

Pd C > Al2O3 5-100 1-10 Alcohol/acid or acetic acid

Best solvents - acetic acid or alcohol + HCl or H2SO4

Pt > Pd C >> Al2O3 5-100 1-10 Low polarity solvent Use Neutral low polar solvents

Pd C 5-100 1-10 Alcohol with water & acid

Imine intermediate hydrolyzed by water.

1.8 Nitriles



Reaction Pressure

Solvents COMMENTS

(deg. C) (BAR)

Rh >> Pd C > > Al2O3 5-100 1-10 Various Alcohol + Acid or ammonia to minimize coupling reactions

Pd > > Rh C >> Al2O3 5-100 1-10 Acidic solvent Mineral acid/acetic acid or mineral acid/alcohol

1.9 Oximes



Reaction Pressure

Solvents COMMENTS

(deg. C) (BAR)

Pd C > > Al2O3 5-100 1-10 Low polarity solvent X = Cl, Br or I. Basic conditions favored.

Pd C >BaSO4 5-50 1-3 Nonpolar solvent Reflux. Use N- or S- compounds as modifiers + halogen aceptors.

Ru C > Al2O3 200-280 200-300 None or an alcoholic solvent

Promoted by Sn.

Reactant Product

Pd > Pt Pt = Ru > Rh

C > Al2O3 Al2O3 = CaCO3

50-150 3-50 Basic solvent for Cl & Br; acidic for others

X = OR, OCOR, Cl, Br, NHR. With halogens use alcoholic KOH or

NaOH, with others use alcoholic HCl or acetic acid.

Pd C >> Al2O3 50-150 1-10 Acidic or neutral solvent

X = OR, OCOR, Cl, Br, NHR. THF Best for C-O cleavage. Aliphatic carbonyls best for C-N cleavage.

1.10 Hydrogenolysis



Reaction Pressure

Solvents COMMENTS

(deg. C) (BAR)Pd C >> Al2O3 50-100 3-50 Acidic solvent Organic base may promote

selectivity.

1.11 Other



Reaction Pressure

Solvents COMMENTS

(deg. C) (BAR)

Pd > Pt C >200 > 1 = 1 Various high boiling point

solvents

Remove liberated H2 by N2 purge or H2 acceptor in liquid phase.

Pd > Pt C > Al2O3 50-300 < 1 No solvent Pd is the only active catalyst.

Pd-62, 111 None 40-80 1-5 Methanol/water E = O, NH. Perform in presence of reoxidant, e.g.Cu(Oac)2/O2.

Pd C 180-250 > 1 = 1 High Boiling Use dinitrotoluene as H2 acceptor.

Pd C > Al2O3 180-250 < 1 High Boiling

2. Dehydrogenation



Reaction Pressure

Solvents COMMENTS

(deg. C) (BAR)

Rh-42, 43, 50, 112

None 50-150 10-50 Aldehydes or toluene

Higher normal to iso-aldehyde ratios obtainable with Rh than with Co.

PPh3:Rh > 50:1 = 50:1

Pd-100, 111 None 50-150 10-50 Various. Base promoted

X = Br, I R = aryl, benzyl, vinyl Base promoted

3. Hydroformylation



Reaction Pressure

Solvents COMMENTS

(deg. C) (BAR)

Pd-100, 101; Pt-100; Rh-40, 112

None 50-150 10-50 Alcohol Use SnCl2 promoter for Pt and Pd. Pt active for terminal alkenes only.

Pd-92, 100, 111 None 50-150 1-20 Various. Base promoted

E = O, NH X = Br, I R = aryl, benzyl, vinyl Base promoted

Pd-100, Rh-112, RhI3

None 100-150 1-50 Carboxylic acids (Rh) or ketones

(pd)

Iodide promotes Rh for !o alcohols. Acidss promote Pd for 2o alcohols.

Product Reactant

Pd-100, 101, 111 None 25-100 1-10 Various Organic base such as Et3N, Bu3N or inorganic bases such as

K2CO3. Ligand such as PPh3 also required if Pd-111 is used.

Pd-100, 101 None 25-100 1-10 DMF Organic base such as Et3N, Bu3N or inorganic bases such as

Pd-100, 111 None 50-150 1-20 Alcohol R = aryl Cu or Co promoted

4. Carbonylation



Reaction Pressure

Solvents COMMENTS

(deg. C) (BAR)

Product Reactant

Rh-100 None 50-150 ca. 1 Various Also possible to decarbonylate some acyl alcohols.

5. Decarbonylation



Reaction Pressure

Solvents COMMENTS

(deg. C) (BAR)

Pt-92, 96, 112, 114

H2[PtCl6]

None 25-75 Ambient None, hydrocarbons

Rh-93, 100 None 25 Ambient MeCN Z isomer obtained with EtOH or propan-2-ol. PPh3 also requiredas

ligand when Rh-93 used.

6. Hydrosilylation



Reaction Pressure

Solvents COMMENTS

(deg. C) (BAR)

Product Reactant

Pd-62, 92, 100, 101, 111

None -10-80 ca. 1 Various M = Li, Mg, Zn, Zr, B, Al, Sn, Si, Ge, Hg, Ti, Cu, Ni.

Pd-92, 100, 111 None 50-150 1-3 Amine or toluene X = Br, I, Otf. Base required as HX Scavenger.

Pd-92, 111 None 25-100 - Various Organic and inorganic bases can be used. Various ligands can be

Pd-62, 92,101, 106, 111

None 25-100 - Various Phosphineligand required where Pd-62, 92, 111 are used. Base

required.

7.1 Heck



Reaction Pressure

Solvents COMMENTS

(deg. C) (BAR)

Product Reactant

Pd-92, 101, 111 None 25-100 - Various Base required, generally inorganic. Various ligands can be used in

conjunction with Pd precursor e.g. PPh3, P(o-to)3, t-Bu3P.

7.2 Suzuki



Reaction Pressure

Solvents COMMENTS

(deg. C) (BAR)

Product Reactant

Pd-92,111, 106 None 80-100 - THF, toluene Base required, t-BuONa or Cs2CO3. Ligand such as P(o-to)3, t-Bu3P, BINAP required when Pd-

92 or Pd-111 used.

Pd-92, 111 None 80-100 - toluene Specialist ligand required. Base such as K3PO4, NaOH required when R'OH used as substrate.

7.3 Buckwald-Hartwig



Reaction Pressure

Solvents COMMENTS

(deg. C) (BAR)

Reactant Product

Pd-100, 101, 103, 106

None 25-Reflux - THF, dioxane

Various Pd precursors

None 25-100 - Various Base may be required in some instances. M = Li, Mg, Zn, B, Al, Si, Hg

Pd-92, 111 None 25-100 - DMSO Pd-111 usually used in conjunction with BINAP, Pd-92 in conjunction with dppf.

T-BuONa may be required.

Pd-62, 92, 100, 101, 111

None 25-100 - DMF, dioxane, toluene, THF, NMP

Cu(I) may be needed as a co-catalyst.

Pd-92, 100, 101, 103, 105, 106,

None 25-100 - Various M = Li, MgX, ZnX, SnR3

7.4 Organometallics



Reaction Pressure

Solvents COMMENTS

(deg. C) (BAR)

Reactant Product

Pd-100, 101 None 25-reflux - DMF, THF Addition of CuI as a co-catalyst activates acetylene by formation of

copper acetylide. Organic base e.g., NR3 usually used.

Pd-111 None 25-100 - DMF Base required K2CO3 or Na2CO3, Bu4NClalso required. Reaction performed under phase transfer conditions, hence the need for

B 4NClPd-100 None 65 - THF Use Cul as additive.

Pd-62, 100, 111 None 25-reflux - NHEt2, NEt3 The addition of Cul as co-catalyst activates the acetylene by formation of

a copper acetylide. Poor results are obtained without Cul. The use of

amines is critical.

7.5 Sonogashira



Reaction Pressure

Solvents COMMENTS

(deg. C) (BAR)

Reactant Product

Pd-62, 111 None 40-80 1-5 Methanol/water E = O, NH, Perform in presence of reoxidant, e.g., Cu(Oac)2/O2

Pd-92, 111 None 25-100 - Toluene, THF, dioxane

Base required NaOtBu, K3PO4 generally used Specialist ligand

Ru-120 + prop-2-yn-1-ol, NaPF6 + P(Cy)3

None 25-80 Ambient Toluene, dichloromethane

Pd-62 None 65 - THF Use LiCl as additive. Use of a mild reoxidant such as benzoquinone is

required.

Pd-62, PdCl2 None 65 - THF Use NaCO3 or NaH as additives.Product Reactant

PdCl2 None 80 - Acetonitrile

Pd-111, PdCl2 None 25-65 - THF Lithiation of the alcohol using n-BuLi in THFis requried as the initial step. Palladium precursor used in

conjunction with PPh3.

Pd-92,101,111 None 25-65 - THF Ligand required when using Pd-92 or Pd-111. Asymetric induction can be achieved using a chiral ligand.

Pd-111 None 100 - DMF Base required, NBu4Cl. Ligand such as PPh3 is also required.

7.6 Other



Reaction Pressure

Solvents COMMENTS

(deg. C) (BAR)

Product Reactant

Pd-111; Rh-110, 115 None 20-50 ca. 1 Various Asymetric cyclopropanation possible with chiral ligands.

8. Cyclopropanation



Reaction Pressure

Solvents COMMENTS

(deg. C) (BAR)

Product Reactant

Ru-100, 130 None 25-110 Ambient MeCN, PhCl, toluene

dichloromethane

N-methyl-morpholine-N-oxide or oxygen used as co-oxidant.

TEMPO also required as ligand when Ru-100 used.

Pt, Pd, Ru C, Al2O3 30-70 1-3 Toluene, hydrocarbons

Use air as oxidant.

Pt, Pd, Ru C, Al2O3 '30-70 1-3 Toluene, hydrocarbons

Use air as oxidant.

Ru-100, 130 None 25-110 Ambient MeCN, PhCl, toluene

dichloromethane

N-Methyl-morpholine-N-oxide oroxygen used as co-catalyst.

TEMPO also required as ligand when Ru-100 used.

Pt > Pd C 40-60 1-5 Aqueous Basic pH (8-10) essential.

9.1 Alcohols to Carbonyls



Reaction Pressure

Solvents COMMENTS

(deg. C) (BAR)

Product Reactant

OsO4/ K2[OsO2(OH)4]

None 0-50 ca. 1 t-butanol, water, THF

Oxidants such as N-methylmorphine N-oxide or

K3Fe(CN)6 preferred. Asymetric hydroxylation possible with chiral

ligands.

9.2 Dihydroxylation of Alkenes



Reaction Pressure

Solvents COMMENTS

(deg. C) (BAR)

Product Reactant

Pd-111 None 20-50 1-5 Acetic acid or alcohol

O2 or H2O2 used as oxidant. Cu2+ co-catalyst.

9.3 Oxygen Insertion Reactions



Reaction Pressure

Solvents COMMENTS

(deg. C) (BAR)

Product Reactant

RuCl3, Ru-100 None 25-70 ca. 1 Various H2O2 or NaOCl oxidant.

PdCl2 None - - Water, DMF. Aq. HCl

Use CuCl2/O2 as additives.

9.4 Other


vulcan catalytic reaction guide - (106) heterogeneous reaction mechanisms

Technology

process economics

catalyst design

catalyst separation

precious metal catalysts

situ exsitu sulfiding

mass transport

choice of metal

powdered supports