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New Stationary Phase for Chromatography.

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phosphate buffer. The reaction mixture is then extracted
with three 25-ml portions of ether. Distillation of the residue
left by the dried ether solution at 20-22°C/0.05 torr gives
0.900 g (38 %) of ( 6 d ) as a pale yellow liquid.
1
3
2
I
Route B:
5.2 g (20 mmole) of (IOd) ( R 2 = C H 3 ) in 50 ml HzO is added
dropwise with stirring t o 2.07 g (15 mmol) of K 2 C O 3 in
10 ml of H20 a t 40-45 "C. After one hour the filtered solution
is extracted with four 40-ml portions of ether. Working up as
for route A gives 1.722 g (55 %) of a yellow liquid that is
identical with ( 6 d ) prepared via route A.
Received: April 22, 1969
[ Z 990 IEI
German version: Angew. Chem. 81, 465 (1969)
~
[*I Prof.
Dr. S. Hiinig and Dipl.-Chem. G . Biittner
Institut fur Organische Chemie der Universitat
87 Wiirzburg, Rontgenring 11 (Germany)
[l] a) P. C. Huang and E. M . Kosower, J. Amer. chem. SOC.90,
2354 (1968); b) 90, 2362 (1968); c) 90, 2367 (1968).
[ 2 ] P . C. Huang and E. M . Kosower, J. Amer. chem. SOC.89,
3911 (1967).
[3] For nomenclature of diazenes, see ref. [lb].
[4]Adduct from diazene + 2 cyclohexanone: E . Schmitz, R.
Ohme, and E . Schramm, Liebigs Ann. Chem. 702, 131 (1967).
[5] S. Hiinig and J . Crnnter, Angew. Chem. 80, 1000 (1968);
Angew. Chem. internat. Edit. 7, 943 (1968).
j6] J . P. Freeman and C. P . Rnthjen, Chem. Commun., in press.
[7] G. Biittner, Diplomarbeit, Universitat Wiirzburg 1968. Analyses, molecular weights, and NMR-Spectra correspond to the
calculated values.
[8] Compare Table in ref. [la].
[9] S. Hiinig, L . Geldern, and E. Liicke, Angew. Chem. 75, 476
(1963); Angew. Chem. internat. Edit. 2, 327 (1963); Chem. Ber.,
in press.
[lo] a) Th. Eicher, S. Hiinig, and H . Hansen, Angew. Chem. 79,
681 (1967); Angew. Chem. internat. Edit. 6, 699 (1967); Chem.
Ber., in press; b) Th. Eicher, S. Hiinig, and P. Nikolaus, Angew.
Chem. 79, 682 (1967); Angew. Chem. internat. Edit. 6,700 (1967);
Chem. Ber., in press.
[I 11 J . Cramer, Dissertation, Universitat Wiirzburg 1968.
[121 S. Hiinig, G. Biittner, and J . Cramer, unpublished experiments (1968).
New Stationary Phase for Chromatography
By I . Halrisz and I. Sebestian[*]
60 30
tt
tt
(sec)
(min)
Fig. la) Gas chromatographic separation in a packed column. Stationary phase: Porasil C/3-hydroxypropionitrile(conditions not optimized).
0 = methane, 1 =- ethane, 2 - propane, 3 = propene. T .r= 28 " C .
Internal diameter of the column (i.d.): 2 mm; column length (L): 1 m ;
sieve fraction (dp): 75-100 pm; carrier gas: Nz; time averaged linear
6.3 cm/sec; sample weight (s): 1-100 pg.
velocity of the carrier gas
(u):
Fig. 1. b) 1 = methane, 2 = n-pentane, 3 = cyclohexane, 4 = 2,4-dimethylpentane, 5 = methylcyclohexane, 6 - 2,2,4-trimethy~pentane,
7 = 2,3,4-trimethylpentane, 8 - n-octane, 9 = 2,2,5-trimethylhexane,
10 = diethylether.
Column and carrier gas as in Fig. la. l p
7- - 121 oc.
.-
5.5 atm;
u
5.7 cni/sec;
Characteristic data f o r propene (Fig. la), cyclohexane, and ether
(Fig. Ib).
partition ratio k'
number of theoretical plates n
number of effective plates N
n/r (sec-1)
N / r (sec-1)
2.9
2.27
16.5
A liquid chromatographic separation on the same stationary
phase with a narrower sieve fraction is illustrated in Fig. 2.
Almost one effective plate per second was generated for N,Ndimethylaniline, this rate being comparable with values
achieved in routine gas chromatographic separations.
L
The esterification of polysilicic acids with alcohols has already been described[ll. Rossi e t nl.121 resolved C1 to C4
hydrocarbons in gas chromatographic columns packed with
silica esterified with benzyl or lauryl alcohol. This separation,
however, was not faster than those on other stationary phases.
We have esterified the porous glass "Porasil C" [2a] (having
silanol groups o n its surface, specific surface area 50m*/g,
pore radius 100-200 A) with 3-hydroxypropionitrile a t
180 "C. The esterified product was extracted with methylene
chloride and dried.
The gas and liquid chromatographic equipment used in these
experiments was similar t o that used in previous studies [31.
The rapid gas chromatographic separation of C1 t o C 3 hydrocarbons is shown in Fig. l a . The vapor pressure of the stationary phase is extremely small; the noise level of the baseline
could be neglected although the sample weighed only 10-8 g.
This is of considerable importance if quantitative analysis is
desired. The rate of separation achieved in this packed column is extremely high: 42 theoretical (a)or 23 effective plates
( N ) , are generated per second. Values of only 0.1 to 2 effective
plates per second are obtained with conventional packed
columns 141.
Other hydrocarbons were resolved in the same column as
shown in Fig. 1b. The peak due to the polar ether is symmetrical although the partition ratio is unusually high (k '= 12.4).
Angew. Chem. internat. Edit.
Vol. 8 (1969) / No. 6
Fig. 2. Liquid chromatographic separation at 20 "C. Stationary phase:
Porasil C/3-hydroxypropionitrile(conditions not optimized). I = toluene (k' = 0); 2 = N,N-dimethylaniline (k' = 2.5); 3 = 2,6-xylidine
(k' = 9.6).
i.d. 2 3 m m ; L = 40 cm; d p = 60-75 vm; mobile phase: n-heptane
(liquid); - I p -.29 atm; I( - 5 cmisec; s = 40 vg; U V detector (cell volume 1 PI).
Characteristic data for N,N-dimethylaniline and 2.6-xylidine.
height equivalent to an theoretical plate k (mm)
hight equivalent to a n effective plate H ( m m )
nit (sec-1)
N / t (sec-1)
12
6.2
1.2
0.9
13
11
0.36
0.32
453
The organic compounds of the stationary phase described
above are orientated like bristles o n the surface of the inorganic compounds 51. Consequently the speed of the mass
transfer is considerably higher here than in liquid stationary
phases.
Further gas chromatographic experiments with columns
packed with such “brushes” have shown, that the height
equivalent to a theoretical plate (h) is independent of: (i) the
nature of the sample (paraffins, aromatics, ether, esters,
chlorinated hydrocarbons have been injected); (ii) the tem-
agents[sl, or ketenesW We have now prepared alkyl- o r
aryl-substituted a-chloro enamines by controlled dehydrochlorination of the readily available a-chloro iminium chloridesC71 ( 3 ) .
R3
1
1
R4
B.p.
( “C/torr)
20
20
20
20
-20
20
-20
-20
CH 3
CH3
H
H
H
H
H
H
70
62
57
57
60-70
60-70
60-70
60-70
95-lOO/I 5
95-100/15
85-901 14
98/8
- Icl
Ibl
[bl
[bl
[bl
-
[cl
[cl
lcl
[a] A = triethylamine, B = pyridine.
[b] Yields 60-70%; determined by titration with bromine or with NaOH after hydrolysis.
[c] Distillation of ( I d ) - [ I f ) gave the corresponding cyclobutenecyanines (51, possibly via
the ynamines.
perature of analysis (70-140 “ C ) ;(iii) the partition ratio (k’ =
1-140); and (iv) the sample size (10-8 t o 10-3 g in acolumn
with internal diameter of 2 mm).
Received: April 8, 1969
[Z 987 IE]
German version: Angew. Chem. 81, 464 (1969)
Physical and spectroscopic data for the a-chloro
exclude the presence of a substantial amount of
form at equilibrium. However, the compounds
expected versatile behavior as exemplified in the
reactions:
1. Addition
[*I Prof. I. Halasz and Dip1.-Ing. I. Sebestian
(Fellow of the Alexander von Humboldt Foundation)
Institut fur Physikalische Chemie der Universitat
6 Frankfurt/Main, Robert-Mayer-Strasse 11 (Germany)
[ I ] R . K . I/er, US-Pat. 2657149 (1952); W. Stuber, G. Bauer, and
K . Thomas, Liebigs Ann. Chem. 604, 104 (1957); G. Bauer and
W. Stober, Kolloid-Z., 2. Polymere 160, 142 (1958); H . Deuel,
J . Wartmann, K . Hutschneker, U . Schobinger, and C . Gudel,
Helv. chim. Acta 42, 1160 (1959).
121 C . Rossi, S. Munari, C . Cengarle, and G. F. Tealdo, Chim. e
Ind. (Milano) 42, 724 (1960).
[2a] Produced by Waters Assoc. Inc., Framingham, Mass. (USA).
[3] H. Bruderreck, W. Schneider, and I. Halasz, Analytic. Chem.
36, 461 (1964); G. Deininger and I . HaMsz, Z . analyt. Chem. 229,
14 (1961); I . Halasz, A. Kroneisen, H . 0.Gerlach, and P . Walkling,
ibid. 234, 81, 97 (1968).
141 A . I . M . Keulemans: Gas Chromatography. Reinhold Publ.
Comp., New York 1957, p. 49; E. Buyer: Gas Chromatographie.
Springer, Berlin 1962, p. 85; C. G. Scott, J. Inst. Petroleum 45,
118 (1959).
[ 5 ] R . K . Iler: The Colloid Chemistry of Silica and Silicates.
Cornell University Press, Ithaca 1955, p. 256.
Alkyl and Aryl a-Chloro Enamines
By L. Ghosez, B. Haveaux, and H. G. Viehe[*1[11
To the best of our knowledge a-chloroenamines ( I ) without
stabilizing electronegative (3-substituents [*I such as fluorine,
chlorine, or carbonyl are hardly known. A brief report 131 on
two representatives of this class has remained unconfirmed
since 1929.
(1)
1 .l. Hydrolysis:
(fa)
Hz0
(CH&CH-CO-NC5Hlo
+ HCI
(100%)
1.2. Formation of a-chloro iminium salts:
dry HCI
@
+ (CH&CH-C(CI)=NCSH~~CI~
( l a ) SO”C,ether
2. Eliminations yielding ynamines. a-Chloro enamines (1)
may produce ynamines as well as their corresponding achloro iminium chlorides by elimination of hydrogen chloride. The stepwise formation of phenylynamine with triethylamine at room temperature shows the unusually mild conditions of this acetylene synthesis:
3. Acylation. a-Chloro enamines are less readily acylated
than enamines or ynamines; even the relatively more reactive
p-monosubstituted a-chloro enamines condense only with
the most powerful acylating agents. This indicates that the
a-chlorine substituent effectively reduces the nucleophilicity
of the 8-carbon atom.
(2)
(I) or (2) have been postulated as intermediates in the synthesis of ynamines from a-halogeno iminium salts 141 and in the
reaction of ynamines with protonic acids 151, alkylating
454
enamines
the polar
show the
following
4. Nucleophilic chlorine substitution. One outstanding
chemical characteristic of a-chloro enamines is their exceptional reactivity in nucleophilic substitution reactions.
Angew. Chem. infernaf.Edit. 1 VoI. 8 (1969) 1 No.
6
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