Electronic Supporting Information
Facile Synthesis of Formaldehyde based Polyether(-Carbonate) Polyols
Jens Langankea, Jörg Hofmannb, Christoph Gürtlerb, Aurel Wolfa*
a
Bayer Technology Services GmbH, 51368 Leverkusen, Germany
b
Bayer MaterialScience AG, 51368 Leverkusen, Germany
Correspondence to: Aurel Wolf, (E-mail: aurel.wolf@bayer.com)
Materials:
All chemicals and solvents were purchased from commercial suppliers and used as received.
Propylene oxide (≥ 99.5 %) and toluene (≥ 99.8 %) were obtained from Sigma-Aldrich. Compressed
CO2 (≥ 99.995 %, steel cylinder) and liquefied ethylene oxide (≥ 99.9 %, dip-tube equipped steel
cylinder) were obtained from Linde AG. The used paraformaldehyde (96 %, no specification
regarding the average molecular weight was given) and propylene carbonate (99.5 %) were obtained
from Acros Organics. The used CO/Zn-DMC catalyst was prepared by aqueous co-precipitation of
ZnCl2 and K3[Co(CN)6] in the presence of t-BuOH and polypropylene glycol 1000 as ligands following
the literature (for details see patent example #6 from J. Hofmann, S. Ehlers, B. Klinksiek, T. Fechtel,
M. Ruhland, J. Scholz, F. Foehles, U. Esser, (Bayer AG) WO 2001/080994, April 17, 2001.).
General Synthesis Protocol:
A typical synthesis of pFA-PO, pFA-EO, and pFA-PO/CO2 was performed in standard lab autoclave
set-up equipped with epoxide dosing (HPLC pump to feed propylene oxide (PO) or liquefied ethylene
oxide (EO)) and gas supply (N2 and/or CO2). The reaction was started by the addition of epoxide to
the active Co/Zn-DMC catalyst (up to 0.5 wt.-% of the final product) and paraformaldehyde (pFA)
dispersed in an aprotic solvent (pFA/solvent = 1:2 w/w) under 5 bar N2. In case of pFA-PO and pFAEO toluene was used as solvent. The synthesis of pFA-PO/CO2 was performed in propylene
carbonate and 50 (entry 5) / 60 bar (entry 6) gaseous carbon dioxide were applied as co-monomer in
the beginning of the co-oligomerization. The reaction was performed at 100 °C and the amount of
added epoxide is calculated from the desired molecular weight of the final product. The reaction
progress was monitored by pressure decrease. A stationary pressure was observed when complete
conversion of epoxide was reached. After cooling to room temperature the reaction mixture was
slowly degassed and the solvent was evaporated under reduced pressure to yield the isolated polyol
product. A thin film evaporator (FTE) unit was used to remove propylene carbonate at 120 °C and
0.1 mbar. If toluene was applied in the synthesis a Büchi rotavap at 60 °C and 10 mbar was sufficient
for the work up step.
Analytics:
a)
1
H- and 13C-NMR
All isolated products were analyzed by 1H- and 13C-NMR spectroscopy. The samples were
dissolved in deuterated chloroform and measured on a Bruker spectrometer (DPX 400, 1H:
400 MHz, 13C: 100 MHz). The relevant resonances in the 1H-NMR spectra (based on
TMS = 0 ppm) were used for integration. Taking the intensities into account, the relative
weight fractions were calculated (as given in Tab. 1). The attached proton test (APT) routine
was used to identify the carbon resonance signals by 13C-NMR.
pFA-PO
H-NMR (400 MHz, CDCl3):  = 1.00-1.24 (m, 3 · H, CH3), 3.40-4.40 (m, 3 · H, CH and CH2 in
polypropylene oxide moieties), 4.60-5.00 (m, 2 · H, CH2 in polyoxymethylene moieties) ppm.
1
C-NMR (100 MHz, CDCl3):  = 95.5-88.9 (CH2), 77.3-70.5 (CH2), 75.3-72.0 (CH), 19.317.2 (CH3) ppm.
13
pFA-PO/CO2
H-NMR (400 MHz, CDCl3):  = 1.00-1.24 (m, 3 · H, CH3 in polypropylene oxide moieties),
1.24-1.40 (m, 3 · H, CH3 in carbonate moieties), 3.40-4.40 (m, 5 · H, CH and CH2 in
polypropylene oxide moieties and CH2 in carbonate moieties), 4.60-5.20 (m, 3 · H, CH2 in
polyoxymethylene moieties and CH in carbonate moieties) ppm.
1
C-NMR (100 MHz, CDCl3):  = 155.0 (C), 94.1-90.6 (CH2), 73.5-71.5 (CH), 71.9-70.7 (CH2),
19.1-15.6 (CH2) ppm.
13
pFA-EO
H-NMR (400 MHz, CDCl3):  = 3.50-3.90 (m, 4 · H, CH2 in polyethylene oxide moieties), 4.605.00 (m, 2 · H, CH2 in polyoxymethylene moieties) ppm.
1
C-NMR (100 MHz, CDCl3):  = 96.5-89.5 (CH2), 70.1-61.3 (CH2) ppm.
13
b) Size Exclusion Chromatography (SEC)
All obtained products were analyzed by SEC. The procedure was performed in accordance
with ISO/DIN 55672-1 (Gel permeation chromatography - Part 1: Tetrahydrofuran (THF) as
elution solvent) using THF as eluent (flow rate 1.0 mL · min-1; columns: 2×PSS SDV linear M,
8×300 mm, 5 μm; RID detector). Standardized polystyrene (PS) samples of known MW were
used for calibration, and the chromatogram was referenced against the absolute mass of
these PS calibration polymers. Thus, uncorrected number- (Mn) and weight-average
molecular weights (Mw) of these triblock diols were obtained by this method. The molecular
weight distribution (MWD) was calculated from Mw/Mn ratio.
In addition to the SEC elugrams (see Fig. 2 in the paper) the MW based SECs of the three
polyol types are given in Fig. S0.
Fig. S0: SEC calibrated with PS for pFA-PO, entry 2 (left), pFA-EO, entry 3 (middle) and pFAPO/CO2 , entry 6 (right) polyol samples
c) Hydroxyl Values (OH#)
The hydroxyl values (OH#) of the isolated products (Tab. 1, entries 1 and 6) were determined
according to ISO/DIN 53240-2 standard (Determination of hydroxyl value - Part 2: Method
with catalyst) and given in mg KOH/g polyol.
d) Dynamic Viscosity
The dynamic viscosities of the isolated products (Tab. 1, entries 4 and 6) were determined
according to ISO/DIN 53018 standard (Viscometry - Measurement of the Dynamic Viscosity
of Newtonian Fluids with Rotational Viscometers) and given in mPa · s.
e) Thermogravimetric Analysis (TGA)
The thermogravimetric analyses were performed on a Mettler Toledo TGA/SDTA851 by
heating samples of 5-10 mg with 5 K ∙ min-1 from room temperature to 500 °C under argon
atmosphere (80 mL · min-1). The weight loss and the weight loss rate were recorded over
time and temperature.
f)
Differential Scanning Calorimetry (DSC)
The differential scanning calorimetry measurement was performed on a Mettler Toledo
DSC822e following a cyclic temperature program in the range from -80 to 200 °C with a
10 mg sample of pFA-PO (Tab. 1, entry 2). For DSC data interpretation the software STARe
SW 8.10 was used. The observed glass transition (Tg) is shown below.
Fig. S1: Tg of pFA-PO polyol (Tab. 1, entry 2) from DSC
g) Determination of Primary/Secondary OH End Groups
The determination of the primary to secondary OH end group ratio was performed via
quantitative peracetylation of the OH end groups followed by analysis with 1H-NMR. The
peracetylated samples were dissolved in deuterated chloroform and measured on a Bruker
spectrometer (DPX 400, 400 MHz). The acetyl CH3 resonances in the 1H-NMR spectra (based
on TMS = 0 ppm) were used for identification and integration: signal at 2.04 ppm resulting
from acetyl CH3 at secondary position (sec. OH derivative), signal at 2.07 ppm resulting from
acetyl CH3 at primary position (prim. OH derivative). Finally, the prim./sec. OH ratio was
calculated from the acetyl CH3 peak area ratios.
h) MALDI-ToF Mass Spectrometry
A representative MALDI-ToF MS of a typical pFA-PO type polyol which was synthesized
following the above given general synthesis protocol was recorded on an Applied Biosystems
4700 Proteomics Analyzer 7021 mass spectrometer using a dithranol/Li matrix (Fig. S2). The
m/z pattern indicates the ring-opening graft of propylene oxide on pFA for these
formaldehyde based polyether(-carbonate) polyols.
Fig. S2: Representative MALDI-ToF MS of a typical pFA-PO type polyol