06 - catalisi

Principi di

Chimica Industriale

con Esercitazioni

Università di Napoli ”Federico II”

R. Tesser

Catalisi

2014-2015

Catalysis/ Rothenberg, ISBN 978-3-527-31824-7. www.catalysisbook.org

Catalysis: Concepts and Green Applications

Catalisi

R. Tesser


Catalysis/ Rothenberg, ISBN 978-3-527-31824-7. www.catalysisbook.org

Industrial

ecology

Green

engineering

Green

chemistry

Renewable

energy

Practical approaches

Sustainable

development

Strategic goal

Life-cycle

assessment

Catalysis

Waste

management

E-factor,

atom economy

Process

intensification

Operational tools

Monitoring tools

The big picture

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R. Tesser


4

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5

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R. Tesser


The drivers of green chemistry

Green chemistry

Less

hazardous materials

High fines for waste

Producer

responsibility

Government legislation

Lower

capital investment

Lower

operating costs

Economic benefit

Pollution control

Safer

and smaller plants

Improved

public image

Societal pressure

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R. Tesser


Oxidation of diphenylmethanol to benzophenone

O

OH

3 + 2CrO3 + 3H2SO4

+ 2Cr2(SO4)3 + 6H2O

diphenyl methanol

benzophenone

stoichiometric reagents

waste

3

Oxidation of diphenylmethanol to benzophenone

using chromium trioxide and sulfuric acid.

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R. Tesser


8

The role of Catalysis in waste minimization

REPLACE OF ANTIQUATED STOICHIMETRIC METHODOLOGY WITH

CLEANER CATALYTIC ALTERNATVES

Stochiometric reduction with metals (NA, Mg, Zn, Fe) or metal hydrides

(LiAlH4, NaBH4, etc.)

Stochiometric oxidation with permanganate or dichromate

Use of mineral acids (H2SO4, H3PO4, etc.) and Lewis acids (AlCl3, ZnCl2),

often in stechiometric amount, wich cannot be recovered and recycled

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R. Tesser


9

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10

Fine Chemicals and Catalysis: Examples

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11

Fine Chemicals and Catalysis: Examples

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R. Tesser


The four stages of life-cycle assessment

Life-cycle

assessment

Defining

the scope

Inventory

analysis

Impact

analysis

Improvement

analysis

Stage 1 Stage 2 Stage 3 Stage 4

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R. Tesser


Different types of catalysts

copper-zinc crystallites on silica

zeolite (crystalline aluminosilicate) enzyme (biocatalyst)

P P

OMe

OMe

(R,R)-DiPAMP-Rh (organometallic complex)

Rh

H B

F

FF

homogeneous acid catalysts

NH

CO2H

L-proline (organocatalyst)

Catalisi

R. Tesser


Examples of chemo- and diastereoselectivity

+ CO + H2

C5H11

O

C5H11

O

+

Rh complex

nonanal iso-nonanal

+ O2

-pinene

CrCl3

-pinene oxide diastereomers

verbenone

O

O

O

+ +

N

MeO

+ H2

prochiral imine (R)-enantiomer

NH

MeO

NH

MeO

+

(S)-enantiomer

Ir complex * *

Regioselectivity

Enantioselectivity

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R. Tesser


15

Pd0L4

Pd

L

L

L

Pd

L

L

Ar

X

Ar X

Ligand

R

Ligand

Pd

L Ar

XR

X

Ar

Pd

RL

X

Ar

Pd

R

LH

2x Ligand

Ligandbase:HX

base

base

Ar X

R

Ar R

base:HX

catalyst

Proposed catalytic cycle for the Heck reaction, showing a the various catalytic

intermediates and b the black box.

version. Some Pd catalysts exhibit TONs and TOFs of over 100 000 in this reaction.

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16

• In enzymology, turnover number (also termed kcat) is defined as the maximum

number of molecules of substrate that an enzyme can convert to product

per catalytic site per unit of time. For example, carbonic anhydrase has a

turnover number of 400,000 to 600,000 s−1, which means that each carbonic

anhydrase molecule can produce up to 600,000 molecules of product

(bicarbonate ions) per second.

• In other chemical fields, such as organometallic catalysis, turnover number

(abbreviated TON) is used with a slightly different meaning: the number of

moles of substrate that a mole of catalyst can convert before becoming

inactivated. An ideal catalyst would have an infinite turnover number in this

sense, because it wouldn't ever be consumed, but in actual practice one often

sees turnover numbers which go from 100 up to 40 million for Catalase. The

term turnover frequency (abbreviated TOF) is used to refer to the turnover

per unit time, as in enzymology. For most relevant industrial applications, the

turnover frequency is in the range of 10−2 - 102 s−1 (enzymes 103 - 107 s−1).

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R. Tesser


H3C CH2

H

H3CCH2

H

H2

H HH3C

CH2

H

H

H3CCH2

H

H

HH3C CH3

H

CH3CH=CH2CH3CH2CH3

metal crystallite

oxide support

Hydrogenation of propene to propane in

the presence of a supported metal

catalyst (the reverse arrows are omitted

for clarity).

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R. Tesser


Pd0

X

2 + Pd0 + PdIIX2

where X = Cl, Br, I

PdIIX2 + H2 Pd0 + 2HX

biarylaryl halideR

R R

X

2 + H2+ 2HX

RR R

PdII

Combination of two stoichiometric reactions: a the

reductive coupling of halobenzene with Pd0 and b the reduction of PdII

with hydrogen gas creates c a catalytic cycle where the Pd catalyst

shuttles between the Pd0 and PdII species.

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R. Tesser


Figure 1.21

Activity

testing

Mechanistic

studies

Parallel

screening

Novel

reactor concepts

Synthesis tools

Process

intensification

Spectroscopy

Surface science

Microscopy

Characterisation tools

Quantum

mechanics

Molecular

simulations

Data mining

Modelling tools

Kinetic studies

Process

simulations

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R. Tesser


20 R. Tesser


Domande?

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06 - catalisi

Documents

napoli federico

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