Note: Descriptions are shown in the official language in which they were submitted.
l BASFAKTlENGEsELLscHAFT o.z.ooSo/44337
. ..
'~131~4
Preparation Of N-Vinyl Compounds
. - - :
The present invention relates to an improved process for the preparation of N-
vinyl compounds of the general formula I
Rl~
N--CH = CH2 ( 1),
R2
in which R1 and R2 independently denote hydrogen, C1-C20alkyl, c5-c8cycloalkyl,
C~-C~8aralkyl, C~-C~8aryl or c,-c20acyl, where one of the radicals R1 and R2 must
be other than hydrogen, or the grouping Rl-NR2 is a constituent part of a saturated,
0 unsaturated or aromatic heterocyclic five-membered to seven-membered ring,
which can additionally contain up to two further hetero atoms selected from the
group consisting of nitrogen, oxygen and sulfur or up to two keto functions and
may additionally be benzanellated,
..
I~ by the reaction of NH compounds of the general formula Il
R1
/N--H ~11), .
R2 .. :
20 with acetylene at temperatures ranging from 50 to 250C and pressures of from
1 to 30bar in the presence of compounds of the platinum metals acting as
catalysts.
N-vinyl compounds are of interest as monomers for the preparation of polymers
2~ useful in diverse fielcis. Such polymers are employed, for example, as agents for
clarifying drinks, as film formers in hair-setting agents or as dye transfer inhibitors
in detergsnt5.
EPI-A 512,656 (1 ) discloses a process for the preparation of vinyl derivatives of
,0 Broensted-acids, ie hydrogen-active compounds, for example, secondary aromatic
amines, primary aliphatic amines, amides or imides, by reacticn with acetylene in
the gas phase at from 40 to 250C under pressure in the presence of zerovalent
ruthenium on a support material as catalyst, in which the acetylene is diluted with
nitrogen in a ratio by volume of ca 0.07:1 and in which the consumption of the
~ acetylene during the reaction is not controlled. In this manner, eg, N-
vinylsuccinimide, N-vinyl-2-pyrrolidone or N-vinyi--caprolactam ars prepared. ~ . .
~ . .
BASFAKTIENGEsELiscHAFT 0 z oo50/44337
2~3~39'~
In the reference Orf~anometallics Vol. 2 (1983), pp. 1689-1691 (2) M. Rotem and
Y. Shvo reveal the use of specific ruthenium carbonyls, such as Ru3(CO)12, as
catalyst intermediates when adding aliphatic or aromatic carboxylic acids to di- or
mono-substituted acetylenes with the formation of vinyl esters. The ruthenium
s carbonyls are used in this case without support materials, and the reaction takes
place in toluene at ~ 45c under pressure. It may be mentioned, in passing, thatruthenium(lII) chloride is completely inactive when used in this reaction.
It was the object of the invention to provide a more effective and more economical
.0 process giving a better space-time yield and affording the possibility of better
control of the conversion of the acetylene.
Accordingly, we have found ehe process defined above, wherein the acetylene is
diluted in the reactor with an inert gas in a ratio by volume of from 6:1 to 0.5:1
and acetylene is forced in at the rate at which it is consumed.
It is known to the person skilled in the art that operating with acetylene underpressure, in particular at elevated temperatures, involves a safety risk, since
acetylene can explosively decompose. For this reason it has hitherto been
20 considered desirable to strongly dilute the acetylene used in such systems with an
inert medium such as nitrogen as described in (1). Thus it was all the more
surprising to find that in the present invention the acetylene needs to be diluted
with only small amounts of an inert gas in order to overcome the risk of explosion.
The possibility of controlling the acetylene consumption also increases the safety
2- of the process.
Suitable inert gases for diluting the acetylene are primarily argon, carbon
monoxide, propane, and especially nitrogen.
0 The acetylene is diluted with the inert gas preferably in a ratio by volume of from
5:1 to 1:1, in particular from 4:1 to 2:1. The dimension mostly used to determine
the volumes of the gases in this case is their partial pressure in the reactor.
Suitable catalysts are compounds of zero- to octa-valent platinum metals, ie
J0 compounds of ruthenium, rhodium, palladium, osmium, iridium, and platinum. The
preferred platinum metals are palladium, osmium, and in particular ruthenium. Weparticularly prefer palladium(II), osmium(III), and ruthenium(III) compounds such
as PdC12, Oscl3, Ru(lll) acetylacetonate, and in particular RuC;13. It iS possible to use
platinum metals of other valence stages, if desired, for example zerovalent
40 ruthenium carbonyls such as Ru3(CO)12.
BASF~I(TIE~GESELLSCHAFT O Z ooso/44~37
--` 213~94
The catalysts can be applied to support materials such as activated charcoal, silica
gel, aluminum oxide or ion exchanger resins, but it is preferred to use unsupported
catalysts.
s The catalysts are advantageously used in conventional amounts, ie approximately
from 0.05 to 10 mol%, preferably from 0.2 to 5 mol%, based on one equivalent of
NH in the compounds ll.
The reaction is advantageously carried out in an inert organic solvent. Suitablesolvents for this purpose are primarily higher-boiling aliphatic or aromatic
hydrocarbons such as toluene or xylenes, higher-boiling aliphatic or aromatic
halohydrocarbons such as chlorobenzene or dichlorobenzenes, or amides such as
N-methylpyrrolidone or dimethylformamide. These solvents are usually used in an
amount of from 50 to 800wt%, in particular from 100 to 500wt~/o, based on the
weight of the NH compound ll used.
The reaction of the NH compounds ll with acetylene (C2H2) is usually caused to
take place in a sealed pressure-proof reactor ( autoclave). The process is
preferably carried out at temperatures ranging from 100 to 200~, in particular20 from 140 to 1 80C and at pressures of from 10 to 25 b~r, in particular frorn 15 to
22 bar. The reaction time required under these conditions is approximately 3 to 30
hours and is usually from 5 to 25 hours.
Purification of the reaction mixture takes place in the simplest case advantage-2~ ously by distillation of the crude vinylation product. The catalyst employed can be
reused.
Suitable-straight-chain or branched-chain C~-C20alkyl radicals which can be
represented by R1 and R2 are, for example, methyl, ethyl, n-propyl, isopropyl, n-
.0 butyl, isobutyl, sec-butyl, tert-butyl, n-amyl, isoamyl, sec-amyl, tert-amyl, neo-
pentyl, n-hexyl, n-heptyl, n-octyl, 2-ethylh0xyl, n-nonyl, isononyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, isotridecyl, n-tetradecyl, n-pentadecyl, n hexa-decyl, n-heptadecyl, n-octadecyl and n-eicosyl. Of these, c1-C4 alkyl radicals are
preferred.
.~
Suitablo c5-c8cycloalkyl radicals which can be representéd by R1 and R2 are
primarily C5-C8 cycloalkyl such as cyclopentyl and cyclohexyl, as well as
cycloheptyl, cyclooctyl, rnethylcyclopentyl, dimethylcyclopentyl, methylcyclohexyl,
ethylcyclohexyl and dimethylcyclohexyl.
3 ::
BAsFAKrlENGEsELLscHAFT 2 1 3 1 ~ 9 ~ o Z ooS0/44 337
Suitable C7-C~8aralkyl radicals which can be represented by Rl and R2 are, for
example, naphthylmethyl, diphenylmethyl or methylbenzyl, but especially c7-c~8
phenylalkyl such as 1-phenylethyl, 2-phenylethyl, 1-phenylpropyl, 2-phenylpropyl,
3-phenylpropyl, 2-phenylprop-2-yl, 4-phenylbutyl, 2,2-dimethyl-2-phenylethyl, 5-
s phenylamyl, 1 O-phenyldecyl, 1 2-phenyldodecyl or, primarily, benzyl.
Suitable c6-c~8 aryl radicals which can be represented by Rl and R2 are primarily
mono- or di- nuclear residues, which can carry a further one to three cl-C4 alkyl
groups as substituents. Particularly suitable examples of said radicals are
unsubstituted phenyl, o-, m-, and p-tolyl, p-ethylphenyl, cumyl, p-tert-butylphenyl
and - and ~- naphthyl.
Suitable C~-C20acyl radicals are primarily those in which the carbonyl group is
directly adjacent to the Natom, so that amide, lactam, or imide structures are
~s present. Examples of C~-C20 acyl radicals are formyl, acetyl, propionyl, and butyryl.
In a preferred embodiment, those N-vinyl compounds I are prepared by the
process of the invention in which the grouping R1-NR2 is a constituent part of asaturated, unsaturated or aromatic heterocyclic five-membered to seven-
20 membered ring, which can contain a furgher nitrogen atom or an oxygen atom orup to two keto functions and which may additionally be benzanellated.
Suitable NH compounds ll to be converted are, for example:
25 - open-chain aliphatic primary or, preferably, secondary amines such as
dimethylamine, cliethylamine or di-n-butylamine
- cyc!oalkyl-substituted amines such as cyclohexylamine
30 - aryl- and aralkyl-substituted amines such as aniline, n-methylaniline, o-, m-,
orp-toluidine, - or ~-naphthylamina, and benzylamine
- open-chain carboxylic acid amides such as formarnide, N-methylformamide,
acetamide, or propionamide
,~
- lactams such as 2-pyrrolidone, ô-butyrolactam or F-caprolactam
- open-chain or preferably cyclic dicarboxylic acid imides such as succinimide,
maleic acid imide or phthalimide
~0
- saturated or partially unsaturated heterocyclic nitrogen compounds such as
:~
BAsFAKT~ENGEsELLscHAFT 2 1 3 1 ~ 9 ~ o.z.ooso/44337
,
pyrrolidine, 2- or 3-pyrroline, piperidine, morpholine, indoline or isoindoline
- aromatic nitrogen heterocyclics such as imidazole, pyrrole, pyrazole, 1,2,3-
or 1 ,2,4-triazole, indole, isoindole, benzimidazole or 1 H-azepine.
It is possible to use NH compounds Il containing a plurality of NH groups, eg,
aliphatic diamines such as N,N-dialkyl-~-diaminoalkanes or saturated hetero-
cyclics such as imidazolodine or pyrazane.
Particularly preferred NH compounds Il to be converted are 2-pyrrolidone,
imidazole, and -caprolactam.
There is usually used, per NH group in the compounds II, from 0.95 to 1.1 mol,
preferably from 1.0 to 1.05mol, of acetylene, which is easy to control using the.. procedure of the invention.
The process of the invention for the vinyla~ion of the NH compounds ll can be
applied to a large number of different NH compounds without any problem. The N-
vinyl compounds I can be obtained in very good yields and ara essentially free
20 from contamination. Side-reactions such as saponification of carbonamide
groupings or polymerization which otherwise frequently occur are not found to take
place in the process of the invention.
2~ Examples 1 to 7
A mixture of ~ yrams of NH compound, k grams of solvent, and c mmol of platinum
metal compound used as catalyst were placed in a high-pressure autoclave
having a~ capacity of 300mL. After purging with nitrogen, the autoclave was
heated and nitrogen and acetylene were forced in under a pressure of 5 bar until an
overall pressure of 20bar (ratio by volume of C2H2 to N2 3:1) was attained.
Acetylene was th~n pumpcd in at the rato at which it was consumed. On
completion of the reac~ion, the relevant N-vinyl compound was obtained by
distillation of the crude product. Details are listed in the Table below.
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BASFAKTlEN~EsELLscHAFT O-Z. oo50/44337
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;
Ex. NH compound Amount Catalyst Amount Temp. Solvent Amount Reaction time Yieid
a lg] Ç lg] lC] lg] lh] l~]
1 2-pyrrolidone75 RuCI3 6.5 150 toluene 75 24 87
2 2 -pyrrolidone 30 Ru(acac)3 5.3 160 toluene 120 14 77
5 3 2--pyrrolidone 100 RuCI3 9.6 150 20 82
4 2 - pyrrolidone 30 OsCI3 1.7 150toluene 120 18 44
5 imidazole 30 RuCI3 1.3 150 toluene 120 24 64
6 succinimide 30 RuCI3 9.5 150 NMP 120 7 72
7 2-pyrrolidone75 Ru(açac)3*) 2.5 160 toluene 75 24 85
acac = acetylacetonate,
NMP = N-methylpyrrolidone
*) 5 mmol of pyridine added
