The condensation/polymerisation of dimethyl siloxane fluids in a three-phase trickle flow monolith reactor

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Abstract

For the prodn. of siloxane fluids, the viability of using a multi-channel monolith as a catalyst support system in a three-phase reactor has been studied. The catalyst was tripotassium phosphate (K3PO4). Expts. were performed in a single-channel flow reactor (15 mm i.d. and 500 mm catalyst coated length). The rate of reaction was followed by monitoring the disappearance of the hydroxyl group (-OH). Reaction expts. were performed at a hydroxyl group concn. range from 150 to 170 mol m-3, T=373-413 K and P=7.9 kPa with a nitrogen purge. The max. temp. of operation was restricted to 413 K to avoid the formation of undesirable byproducts. In the regime controlled by chem. kinetics, reaction was of an apparent first order with respect to -OH concn., and in the apparent rate const., the pre-exponential factor was 4.19*10-4 m s-1, and the apparent activation energy was 16.1 kJ mol-1. These are only valid for the operating pressure and purge gas flowrate used, as both of these are shown to affect water removal from the liq. phase and, hence, reaction rates. Mass transfer coeffs. from the liq. to the catalyst surface were estd. and these increased rapidly with flowrate and were higher than expected for a falling liq. film.
Original languageEnglish
Pages (from-to)275-281
Number of pages7
JournalCatalysis Today
Volume69
Issue number1-4
Publication statusPublished - 2001

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Siloxanes
Polycondensation
Hydroxyl Radical
Catalysts
Fluids
Channel flow
Catalyst supports
Reaction rates
Byproducts
Phosphates
Nitrogen
Mass transfer
Activation energy
Gases
Kinetics
Water
Monitoring

Keywords

  • Polysiloxanes Role
  • Activation energy
  • silicone fluid polymn three phase trickle flow monolith reactor
  • Polymerization kinetics (the condensation/polymn. of di-Me siloxane fluids in a three-phase trickle flow monolith reactor)
  • Polymerization catalysts
  • Mass transfer
  • PREP (Preparation) (the condensation/polymn. of di-Me siloxane fluids in a three-phase trickle flow monolith reactor)
  • SPN (Synthetic preparation)

Cite this

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title = "The condensation/polymerisation of dimethyl siloxane fluids in a three-phase trickle flow monolith reactor",
abstract = "For the prodn. of siloxane fluids, the viability of using a multi-channel monolith as a catalyst support system in a three-phase reactor has been studied. The catalyst was tripotassium phosphate (K3PO4). Expts. were performed in a single-channel flow reactor (15 mm i.d. and 500 mm catalyst coated length). The rate of reaction was followed by monitoring the disappearance of the hydroxyl group (-OH). Reaction expts. were performed at a hydroxyl group concn. range from 150 to 170 mol m-3, T=373-413 K and P=7.9 kPa with a nitrogen purge. The max. temp. of operation was restricted to 413 K to avoid the formation of undesirable byproducts. In the regime controlled by chem. kinetics, reaction was of an apparent first order with respect to -OH concn., and in the apparent rate const., the pre-exponential factor was 4.19*10-4 m s-1, and the apparent activation energy was 16.1 kJ mol-1. These are only valid for the operating pressure and purge gas flowrate used, as both of these are shown to affect water removal from the liq. phase and, hence, reaction rates. Mass transfer coeffs. from the liq. to the catalyst surface were estd. and these increased rapidly with flowrate and were higher than expected for a falling liq. film.",
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author = "S Awdry and Kolaczkowski, {S T}",
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language = "English",
volume = "69",
pages = "275--281",
journal = "Catalysis Today",
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TY - JOUR

T1 - The condensation/polymerisation of dimethyl siloxane fluids in a three-phase trickle flow monolith reactor

AU - Awdry, S

AU - Kolaczkowski, S T

PY - 2001

Y1 - 2001

N2 - For the prodn. of siloxane fluids, the viability of using a multi-channel monolith as a catalyst support system in a three-phase reactor has been studied. The catalyst was tripotassium phosphate (K3PO4). Expts. were performed in a single-channel flow reactor (15 mm i.d. and 500 mm catalyst coated length). The rate of reaction was followed by monitoring the disappearance of the hydroxyl group (-OH). Reaction expts. were performed at a hydroxyl group concn. range from 150 to 170 mol m-3, T=373-413 K and P=7.9 kPa with a nitrogen purge. The max. temp. of operation was restricted to 413 K to avoid the formation of undesirable byproducts. In the regime controlled by chem. kinetics, reaction was of an apparent first order with respect to -OH concn., and in the apparent rate const., the pre-exponential factor was 4.19*10-4 m s-1, and the apparent activation energy was 16.1 kJ mol-1. These are only valid for the operating pressure and purge gas flowrate used, as both of these are shown to affect water removal from the liq. phase and, hence, reaction rates. Mass transfer coeffs. from the liq. to the catalyst surface were estd. and these increased rapidly with flowrate and were higher than expected for a falling liq. film.

AB - For the prodn. of siloxane fluids, the viability of using a multi-channel monolith as a catalyst support system in a three-phase reactor has been studied. The catalyst was tripotassium phosphate (K3PO4). Expts. were performed in a single-channel flow reactor (15 mm i.d. and 500 mm catalyst coated length). The rate of reaction was followed by monitoring the disappearance of the hydroxyl group (-OH). Reaction expts. were performed at a hydroxyl group concn. range from 150 to 170 mol m-3, T=373-413 K and P=7.9 kPa with a nitrogen purge. The max. temp. of operation was restricted to 413 K to avoid the formation of undesirable byproducts. In the regime controlled by chem. kinetics, reaction was of an apparent first order with respect to -OH concn., and in the apparent rate const., the pre-exponential factor was 4.19*10-4 m s-1, and the apparent activation energy was 16.1 kJ mol-1. These are only valid for the operating pressure and purge gas flowrate used, as both of these are shown to affect water removal from the liq. phase and, hence, reaction rates. Mass transfer coeffs. from the liq. to the catalyst surface were estd. and these increased rapidly with flowrate and were higher than expected for a falling liq. film.

KW - Polysiloxanes Role

KW - Activation energy

KW - silicone fluid polymn three phase trickle flow monolith reactor

KW - Polymerization kinetics (the condensation/polymn. of di-Me siloxane fluids in a three-phase trickle flow monolith reactor)

KW - Polymerization catalysts

KW - Mass transfer

KW - PREP (Preparation) (the condensation/polymn. of di-Me siloxane fluids in a three-phase trickle flow monolith reactor)

KW - SPN (Synthetic preparation)

M3 - Article

VL - 69

SP - 275

EP - 281

JO - Catalysis Today

JF - Catalysis Today

SN - 0920-5861

IS - 1-4

ER -