DIRECT CATALYTIC OXIDATION OF LOWER ALKANES
375
+
–
[
PyH Ac O ]=2 mol/L), 0.25 mL of an aqueous soluꢀ
f
[P], mol/L
0.30
–2
tion of [RhCl ] = 5
.15 mol/L, 0.23 mL of H O, 2.42 mL of CF COOH,
×
10 mol/L and [NaCl] =
3
0
2
3
and 0.4 g (5 mmol) of pyridine were placed in the conꢀ
0
0
0
0
.25
.20
.15
.10
+
–
tainer. Pyridinium trifluoroacetate [PyH Ac O
]
f
forms in situ to consume 0.4 mL of CF COOH. The
3
amounts of the components to be introduced were
controlled on an analytical balance for greater accuꢀ
racy; then, the contents of the container was charged
to the reactor in which a weighed portion of copper triꢀ
fluoroacetate (0.0725 g, 0.25 mmol) had been already
placed. The reactor was sealed, and gases were fed:
CH4 = 6.0 MPa, O2 = 0.8 MPa, and CO = 1.6 MPa.
Propane was dosed from a graduated gas burette by
means of liquefaction with liquid nitrogen in a special
condenser installed before the reactor. After thawing,
the condenser was connected with the reactor and the
gases were fed through the condenser at
He = 4.0 MPa, O2 = 0.8 MPa, and CO = 1.6 MPa. A
0.05
0
1
2
3
4
+
–
[PyH Ac O ], mol/L
f
Fig. 1. The yield of propane oxidation products ([P]) in the
presence of pyridinium trifluoroacetate on the rhodium–
copper–chloride catalytic system in the CF COOH–H O
1
0ꢀMPa standard pressure gage having a division value
of 0.04 MPa was mounted in the gas line for accurate
gas dosage. After supplying the gases, the reactor valve
was closed, jointed with a thermostat preliminarily
heated up to a reaction temperature, and agitation was
turned on. After the run was completed, the reactor
3
2
3
medium: [RhCl ] = 5
×
10− mol/L; Cu(Ac O) = 1
×
3
f
2
0⎯1 mol/L, [NaCl] = 1.5
10− mol/L,
2
1
×
m
= 0.5,
H O
2
T
= 80
°C
, propane = 12 mmol, О2 = 0.8 MPa, CO =
i
1
.6 MPa, He = 4.0 MPa; 2.5 h: ( ) acetone, ( ) Ac OPr ,
was cooled with tap water to
≈12°C
and the gas phase
f
and ( ) Ac OPr. Small amounts of methyl and ethyl trifluꢀ
was released into an evacuated ~2ꢀL glass flask. The
gas phase and the liquid catalyzate were analyzed using
GC and GC–MS techniques. The concentrations of
the catalytic system components and analysis results
are given in the tables and figures.
f
oroacetates (absent in graph) were also found.
split ratio was used, Tinj = 220°C, a temperatureꢀproꢀ
grammed column was used, Tstart = 40°C (4 min),
Tend = 250°C (4 min), temperature rise was 10
The ionization mode was an electron impact of 70 eV,
a resolution was no less than 2.0 M (where M is m/z
within 18–131 m/z range. To determine the isotope
°
C/min.
Analysis
)
The gas phase was analyzed on a Model 3700 chroꢀ
matograph (Khromatograf pilot plant, Moscow) at
55°C
with a thermal conductivity detector and helium composition, the spectra were recorded in the scanꢀ
as the carrier gas. Columns:
a particle size of 0.2–0.3ꢀmm,
He = 30 mL/min (O , N , CH4, CO); Porapak Q with software suites were used for GC–MS data acquisition
5
Å molecular sieves with ning mode within the 15–100 m/z range; the scan time
= 3 m, = 3 mm, was 100 ms. The Lucy ver. 2.0 and AMDIS ver. 2.62
l
d
2
2
a particle size of 0.115–0.200ꢀmm,
l = 2m, d =
and processing. For sampling, the reaction mixture
was placed into a test tube sealed with a membrane,
2
.5 mm, He = 20 mL/min (CO2, propane).
The liquid phase was analyzed on a Kristallyuks
000M gas chromatograph with flameꢀ
heated up to ~60
°
C
, and the headspace was sampled
. The
L) was introduced into the chroꢀ
4
a
with a chromatographic syringe heated to ~50
°C
ionization detector, using a NetChrom V2.1 program
and a CPꢀSil 5CB Agilent capillary column, = 25 m,
= 0.15 mm, temperature programming from 40 to
50 at a heating rate of 5°C/min, He = 20 mL/min,
sample (50–100
matograph.
µ
l
d
1
°C
inlet pressure of 1.3 atm, and a split ratio of 1 : 70 to
have a column flow rate of 0.287 mL/min. Sample
preparation before injecting liquid samples into the
vaporizer was practiced.
Sample Preparation for GC
and GCꢀMS Analyses
The nonꢀdemixing catalyzates containing internal
standards were charged in a special reactor having a
chromatographic silicone membrane (septum), and
GC–MS measurements were made with a Delsiꢀ
Nermag Automass 150 instrument equipped with a
DN200 gas chromatograph (Delsi). A CPSil 5 chroꢀ
the reactor was thermostated at 50
Then, the headspace was sampled with a gas syringe
heated to 60 . The sample injected into the chroꢀ
Chrompack) was used. The carrier gas was He, conꢀ matograph of a 100–150ꢀ
L size. Analysis was conꢀ
stant pressure mode of 1.2 bar, an injector with a 1 : 50 ducted in two steps. Firstly, methyl, ethyl, isopropyl,
°C for 20 min.
matographic column (25 m
×
0
.15 mm, df = 1.2 m
µ
°C
(
µ
PETROLEUM CHEMISTRY Vol. 54
No. 5
2014