Continuous flow synthesis of a blocked polyisocyanate: process optimization and reaction monitoring by in-line FT-IR spectroscopy

master's thesis

• Title (croatian): Sinteza zaštićenog poliizocijanata u kontinuiranom protoku: optimizacija procesa i praćenje reakcije FT-IR spektroskopijom in-line
• Author: Gabriel Glotz
• Mentor: Christian Oliver Kappe (mentor)
• Committee member: Snežana Miljanić (predsjednik povjerenstva)
• Committee member: Vesna Petrović Peroković (član povjerenstva)
• Committee member: Željka Soldin (član povjerenstva)
• Committee member: Ines Primožič (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Chemistry); Zagreb
• Defense date and country: 2019-04-08, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry

Abstract

Given that the traditional batch production of blocked isocyanates has significant drawbacks
associated with the exothermic character of the reaction and the high viscosity of the materials
involved, a continuous flow strategy was developed. The neat oxime and the viscous
polyisocyanate were mixed using a Kenics® static mixer and the homogeneous mixture
obtained was fully converted to the target blocked isocyanate in a residence time unit
downstream of the mixer. Real-time reaction monitoring via in-line FT-IR spectroscopy at the
reactor outlet has been implemented, enabling fast optimization of the reaction conditions and
providing a sensitive and reliable control of the product quality. The process has been
intensified by an increase in the flow rate of the reactants, a decrease in the residence unit
volume and a stepwise increase in the temperature of the flow reactor. Full conversion to the
blocked polyisocianate has been achieved at 155 °C after only 15 s of the overall residence
time, providing productivity of ca. 1 kg per hour for a reactor of only 4.5 mL volume.

Abstract (croatian)

S obzirom da tradicionalna serijska proizvodnja zaštićenih izocijanata ima značajne
nedostatke vezane uz egzotermni karakter reakcije i visoku viskoznost tvari koje sudjeluju u
reakciji, razvijena je strategija sinteze u kontinuiranom protoku. Čisti oksim i viskozni
poliizocijanat miješaju se pomoću statičke miješalice Kenics® te se dobivena homogena
smjesa potpuno prevodi u ciljani zaštićeni izocijanat u protočnom reaktoru. Praćenje reakcije
u realnom vremenu provedeno je FT-IR spektroskopijom in-line reakcijske smjese na izlasku
iz reaktora, što je omogućilo brzu optimizaciju reakcijskih uvjeta te osiguralo osjetljivu i
pouzdanu kontrolu kvalitete produkta. Proces je optimiziran povećanjem brzine protoka
reaktanata, smjanjenjem volumena cijevnog reaktora te postupnim povećanjem temperature
protočnog reaktora. Potpuna pretvorba u zaštićeni izocijanat postignuta je pri 155 °C nakon
samo 15 s ukupnog vremena zadržavanja u reaktoru, čime je postignuta produktivnost od
približno 1 kg na sat u reaktoru volumena od samo 4,5 mL.

• Keywords: blocked isocyanates; continuous-flow; continuous processing; in-line analytics; process optimization
• Keywords (english): analitika in-line; kontinuirani process; kontinuirani protok; optimizacija procesa; zaštićeni izocijanati
• Language: english
• URN:NBN: urn:nbn:hr:217:284848
• Study programme: Title: Graduate university studies in chemistry; specializations in: Research programme; Course: Research programme; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra kemije (magistar/magistra kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access; Embargo expiration date: 2021-04-08
• Repository: Repository of the Faculty of Science
• Created on: 2019-04-24 13:04:22