150 / 390
Figure 4:
SEM image of a rust particle covered by precipitate particles (top) and
corresponding EDX spectrum
The aluminum species in the solids have to originate from the product mixture of the direct
synthesis. ICP-AES analysis showed that the mixture contains 150 – 250 ppm aluminum when
it enters the distillation process. A
27
Al-NMR-investigation of several samples of that mixture
found two different aluminum species (Figure 6). The broad signal/shoulder at approximately
90 ppm could be assigned to AlCl
3
by reference measurements while the species generating the
sharp signal at 102 ppm remained obscure. In the first stages of the distillation process the
aluminum concentration in the high boilers of the distillation range rises to 1700 ppm and a
third aluminum species appears at 117 ppm, again showing a broad signal (Figure 7).
Figure 5:
27
Al-MAS-NMR (15 kHz) of solids from the filters of the first silanes
distillation column (black) and from the disilanes distillation column (red)
It was not possible to quantify the ratio of the three species in the spectrum because integration
of the signals is made inaccurate by the quadrupole moment of the aluminum nucleus but it is
Cl
Ca
Ca
Si
C
Ca
Fe
Al
Fe
O
Cl
Fe
0
1
2
3
4
5
6
7
8
9
10
keV
Skalenbereich 2339 cts Cursor: -0.016 (1676 cts)
Spektrum 07
400
300
200
100
0
-100
-200
-300
ppm
MiniSpec -CopyrightCorporateAnalyticsWackerChemieAG
CurrentDataParameters
NAME 2634828C-LIMS
EXPNO
2
PROCNO
1
F2 -AcquisitionParameters
Date
27.05.2014
Time
14.43.15
INSTRUM
spect
PROBHD 4mmMASBB/1H
PULPROG
onepulse
TD
4096
SOLVENT
C6D6Toluol
NS
1024
DS
0
SWH
250000,000 Hz
FIDRES
61,035156 Hz
AQ
0,0081920 sec
RG
128
DW
2,000 usec
DE
6,50 usec
TE
297,8 K
D1
1,00000000 sec
========CHANNEL f1========
NUC1
27Al
P1
1,00 usec
PL1
120,00 db
SFO1
104,2679155 MHz
F2 -Processingparameters
SI
8192
SF
104,267204 MHz
WDW
EM
SSB
0
LB
5,00 Hz
GB
0
PC
1,40
1DNMRplotparameters
CX
28,22 cm
CY
15,73 cm
F1P
499,690 ppm
F1
0,00 Hz
F2P
-381,403 ppm
F2
0,00 Hz
PPMCM
31,22764 ppm/cm
HZCM
0,00000 Hz/cm
Integrale
AlCl
4
-
AlCl
3
142