MDA.HCl - ePosters

Concentration and Mixing Effects on the Production of Amine Hydrochloride
Salts in a Confined Impinging Jet Reactor
Navid F.
1
Ershad ,
1Department
Archie
2
Eaglesham ,
Don H.
2
Jones
and Suzanne M.
1
Kresta
of Chemical and Materials Engineering, University of Alberta, Edmonton, Canada
2Huntsman (Europe) BVBA, Everslaan 45, 3078 Everberg, Belgium.
Chemical precipitation from reactive solutions requires reactants to be mixed at smallest length scales to form fine particles. A Confined
Impinging Jet Reactor (CIJR) was used to produce aminehydrochloride (AHC) salts which are by-products of a desired reaction sequence in
manufacture of polyurethanes. This work investigates the effect of mixing intensity (flowrate) and local concentration (reactant
concentration) on the formation of AHC salts. Results show that different AHC salts can be formed under different process conditions.
Results
Introduction
Introduction to A Problem in Polyurethane Synthesis
Part 1. Characterizing High Concentration compounds
Polyurethanes (PU) are ubiquitous in our everyday lives, where the total size of PU
industrial activity was 8.4 million tons in 2008 and is expected to grow to 9.6 million tons
by 2015.
Results show that filtered compound has a composition of MDA, MDA.HCl and
MDA.2HCl, where more HCl availability to react with amines, results in a higher degree of
chlorination. Five of the purest samples were characterized and used as a reference for
the FTIR, DSC and CHNSCl Elemental Analyses.
In the phosgenation step of PU synthesis, MDA (4,4'-Methylenedianiline) reacts with
phosgene to form MDI (Methylenediphenyl diisocyanate), but an undesired side reaction
results in precipitation of highly insoluble and sticky AHC salts which are subject of study
in this work. This side reaction causes loss of starting material and very expensive
reprocessing.
Titles
Reaction Conditions
MDA
Flowrate
HCl
conc. (%) (mlmin-1) excess (%)
Items
Salts Made
in CIJR
Chemistry of the Process
AHC salts forms as precipitated particles with following simplified reactions:
𝐶𝑂 + 𝐶𝑙2 → 𝐶𝑂𝐶𝑙2
Carbon Monoxide
Chlorine
Phosgene
MDA
Phosgene
Hydrogen Chloride
Carbamyl Chloride
MDA
Hydrogen Chloride Amine hydrochloride
∗
1
of
2
MDA group;
∗∗
100
100
0.5
200
300
5
100
100
5
200
300
MDA.HCl in Theory
MDA.2HCl in Theory
𝑅−𝑁𝐻2 + 𝐻𝐶𝑙 → 𝑅−𝑁𝐻2 . 𝑥𝐻𝐶𝑙∗∗
:𝑅 =
0.5
Sigma Aldrich (97% Pure)
𝑅∗ −𝑁𝐻2 + 𝐶𝑂𝐶𝑙2 → 𝑅−𝑁𝐻𝐶𝑂𝐶𝑙 + 𝐻𝐶𝑙
Description
C
H
N
Cl
C/Cl
E.A.
FTIR
99%
Just
Peak T=262, ∆H=669
TPeak range=252-267
MDA.2HCl MDA.2HCl
99%
Just
Peak T= 249, ∆H=915
57.5 6.0 10.0 26.3 2.19
TPeak range=247-255
MDA.2HCl MDA.2HCl
99%
Just
Peak1 T=92, ∆H=62, TPeak range=90-93
66.5 6.5 11.8 15.0 4.4
MDA.HCl MDA.HCl Peak2 T=189, ∆H=49, TPeak range=187-190
100%
Just
Peak1 T=100, ∆H=37, TPeak range=87-105
66.5 6.6 11.7 15.1 4.2
MDA.HCl MDA.HCl Peak2 T=188, ∆H=80, TPeak range=186-189
57.5 5.9 10.2 26.3 2.19
78.8 7.1 14.1
0.0
66.5 6.4 11.9 15.1
57.6 5.9 10.3 26.2
-
Almost Pure MDA
Peak T= 94, ∆H=102,
TPeak (melting) range= 92-94
4.4
2.2
MDA.HCl in Theory
MDA.2HCl in Theory
N/A
N/A
300X SEM
1500X SEM
250 O.M
100X SEM
DSC Peaks Data T(oC), ∆H(J/g)
300X SEM
1500X SEM
: 𝑥 between 0.5 and 1
Why is mixing important in Reactive Precipitation systems?
 Nucleation and aggregation rates are controlled by mixing and local
concentration.
 Particle growth and agglomeration are dominated by supersaturation-generation
and collisions.
 Particle morphology is controlled by mixing. Uniform mixing results in uniform
particles.
MDA
Increase in Degree of Chlorination
Part 2. Studying Effects of Reaction Variables
2.1. Effect of Varying MDA Concentration on AHC salts
Experimental
Why was the CIJR selected?
Case Study 1
100% HCl
excess and
100ml/min
flowrate
CIJR provides:
 Uniform mixing (initiates homogeneous nucleation)
 Fast mixing and small residence
 Continuous operation
Case Study 2
300% HCl
excess
200ml/min
flowrate
In rapid reactions where uniform concentration and mixing intensity are important,
the CIJR has advantages over the stirred tank, because stirred tanks have wide variation in
dissipation across the mixing volume. Impinging jets can be used when the reaction time
of the desired reaction is smaller than the reactor’s residence time, especially for
crystallization and precipitations.
Highlights:
 Monochlorobenzene (MCB) used as the environment of phosgenation reaction.
The MDA/MCB blend is mixed with dissolved anhydrous HCl(g) in MCB.
 System pressure is set at 4 bar to keep HCl dissolved in MCB
 A venturi is used to disperse HCl gas and dissolve it in MCB
𝑀𝐷𝐴
𝑀𝐶𝐵
1 mm
1 mm
2
Based on E.A.
99% MDA.2HCl
94% MDA.HCl
DSC Data T(oC), ∆H(J/g)
Peak T=262, ∆H=669, TPeak range=252-267
Peak1 T=97, ∆H=44, T
range=86-101
Peak
Both MDA.HCl and MDA.2HCl.
Peak2 T=187, ∆H=73, TPeak range=185-189
Very stronger in MDA.HCl peaks.
5
99% MDA.HCl
Just MDA.HCl
0.5
99% MDA.2HCl
Just MDA.2HCl
2
76% MDA.HCl
Both MDA.HCl and MDA.2HCl.
Stronger in MDA.HCl peaks.
5
100% MDA.HCl
Just MDA.HCl
1 %wt - 600X
Peak3 T=263, ∆H=N/A >450
Peak1 T=92, ∆H=62, TPeak range=90-93
Peak2 T=189, ∆H=49, TPeak range=187-190
Peak T= 249, ∆H=915, TPeak range=247-255
Peak1 T=96, ∆H=32, TPeak range=88-100
Peak2 T=187, ∆H=67, TPeak range=183-188
Peak3 T=260, ∆H=560
Peak1 T=100, ∆H=37, TPeak range=87-105
Peak2 T=188, ∆H=80, TPeak range=186-189
3.5 %wt - 600X
2 %wt - 600X
5 %wt - 600X
2.2. Effect of Varying Flowrate on AHC salts
Flowrate
Description
DSC Data T(oC), ∆H(J/g)
(ml/min) Based on E.A.
Based on FTIR
Peak T=262, ∆H=669, TPeak range=252-267
100
99% MDA.2HCl
Just MDA.2HCl
Case Study 1
Both MDA.HCl and MDA.2HCl.
0.5% MDA in
Peak T= 270, ∆H=59, TPeak range=241-272
200
96% MDA.2HCl
Very
stronger
in
MDA.2HCl
peaks.
blend and
100% HCl
Both MDA.HCl and MDA.2HCl.
Peak1 T= 184, ∆H=14, TPeak range=081-186
300
92% MDA.2HCl
excess
Very stronger in MDA.2HCl peaks. Peak2 T= 272, ∆H=487, TPeak range=270-275
𝐻𝐶𝑙
𝑀𝐶𝐵
Case Study 2
5% MDA in
blend and
100% HCl
excess
𝐴𝐻𝐶/𝑀𝐶𝐵
100
99% MDA.HCl
Just MDA.HCl
Peak1 T=92, ∆H=62, TPeak range=90-93
Peak2 T=189, ∆H=49, TPeak range=187-190
200
86% MDA. HCl
Both MDA.HCl and MDA. Very
stronger in MDA.HCl peaks.
Peak1 T= 92, ∆H=62, TPeak range=89-93
Peak2 T= 189, ∆H=49, TPeak range=187-190
300
72% MDA.HCl
Both MDA.HCl and MDA. Slightly
stronger in MDA.HCl peaks.
Peak1 T= 91, ∆H=21, TPeak range=90-92
Peak2 T= 188, ∆H=42, TPeak range=187-189
Value for flowrate of
300 ml/min
Parameter
Description
Based on FTIR
Just MDA.2HCl
Case study 1, Increase in Blend Strength
Volume of CIJR: approx. 0.12 ml
Residence time range: 25-75 ms
1.5 mm
MDA
Conc %
0.5
0.5 %wt - 600X
4.76 mm
CIJR design
MDA.2HCl
MDA.HCl
Experimental: 1490
Energy Dissipation Rate
(W/kg)
1 time step simulation: 1360
Maximum Velocity (m/s)
7.72
3 time step simulation: 1365
100ml/min - 600X
200ml/min - 600X
300ml/min - 600X
Case Study 2, Increase in Flowrate
Mean velocity contours (m/s) in CIJR
for 300ml/min flowrate.
Process variables
 Blend Strength of MDA/MCB; MDA composition from 0.5 to 5%wt.
 HCl excess; 0-700%
 Flowrate; 100-300 ml/min
Which Analytical Techniques were considered and which ones were
selected?
Method
Elemental
Analysis
FTIR KBr
Pellet
TGA
DSC
SEM (SE and BSE
imaging, EDX)
Optical
Microscopy
Conclusions
 AHC structure depends on MDA concentration more than any other parameter.
 Increase in HCl excess and flowrate results in particles that are more even in shape
and size.
 Higher HCl excess advances reaction to produce higher concentration AHC where
unreacted MDA cannot be found in salts made with high HCl excess amounts.
 Faster mixing, i.e. higher flowrates, reduces the purity of AHC salts perhaps because of
lower residence time in CIJR.
 Very high mixing intensity results in a lower conversion of MDA in the CIJR.
References and Acknowledgements
XRD
Considered?
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Selected?
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1.
2.
3.
4.
Siddiqui, S. W., Zhao, Y., Kukukova A. and Kresta S. M., Characteristics of a Confined Impinging Jet Reactor, Ind. Eng. Chem. Res., 2009, 48
Gibson E K , Amine hydrochloride salts: a problem in polyurethane synthesis, PhD Thesis, University of Glasgow, 2007
Sonnenschein, M. F. and Koonce, W. 2011. Polyurethanes. Encyclopedia Of Polymer Science and Technology.
Six, C. and Richter, F. 2003. Isocyanates, Organic. Ullmann's Encyclopedia of Industrial Chemistry.
This Research has been supported by Huntsman Polyurethanes.