Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
1999-10-08
2002-12-10
Higel, Floyd D (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
active
06492528
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to 1,3-dialkyl-2-imidazolidinones and a manufacturing process therefor.
1,3-Dialkyl-2-imidazolidinones have been extensively used as, for example, an aprotic polar solvent; for example, they are useful as a solvent for a resin such as polyamide, polystyrene, polyester, polyvinyl chloride or a phenol resin; a reaction solvent for various kinds of organic syntheses; or an extraction solvent for extracting an aromatic hydrocarbon from an aliphatic hydrocarbon. Among 1,3-dialkyl-2-imidazolidinones, 1,3-dimethyl-2-imidazolidinone (hereinafter, referred to as “IDMI”) is particularly useful because it is remarkably resistant to a strong base, is little decomposed when heated with a solution of an alkali-metal hydroxide, and therefore, is suitably used as a reaction solvent for dehalogenation of an aromatic organic halide, in particular polychlorobiphenyls.
2. Description of the Prior Art
Various preparation processes for 1,3-dialkyl-2-imidazolidinones have been suggested, in which N,N′-dialkylethylenediamine is involved as a starting material; for example, reacting N,N′-dimethylethylenediamine with trichloromethyl chloroformate as disclosed in JP-A 53-73561; reacting N,N′-dimethylethylenediamine with carbon dioxide as disclosed in JP-A 57-175170; reacting N,N′-dialkylethylenediamine with phosgene in the presence of water and dehydrochlorinating agent as disclosed in JP-As 61-109772 and 61-172862; reacting N,N′-dimethylethylenediamine with urea in the presence of a polar solvent as disclosed in JP-A 7-252230. As the starting material, N,N′-dimethylethylenediamine can be prepared by a well-known process, in which ethylene dichloride and monomethylamine are reacted as described in JP-A 57-120570. The process involves a problem of disposing a large amount of byproduct, sodium chloride contaminated by organic compounds. A reaction of ethylene glycol with monomethylamine in the presence of a homogeneous catalyst consisting of ruthenium and triphenylphosphine has been suggested to prepare N,N′-dimethylethylenediamine as disclosed in J.Organometallic Chem., Vol.407, p.97 (1991). It is, however, difficult to industrially recover and recycle such a homogeneous precious metal catalyst. Thus, it cannot be said to be ideal to produce 1,3-dialkyl-2-imidazolidinone from N,N′-dialkylethylenediamine.
There have been suggested a reductive addition of 2-imidazolidinone and formaldehyde in the presence of a hydrogenating catalyst (JP-A 60-243071) and a catalytic reduction of dialkyl ether of N,N′-hydroxymethylimidazolidinone (JP-B 60-3299) as another attempt to prepare N,N′-dialkylimidazolinones. These also involve the above problem because a starting material is prepared from dimethylethylenediamine, and are impractical because its processes are lengthy.
There have been disclosed interesting processes, i.e., reactions of N-alkylmonoethanolamine with an alkylamine such as monomethylamine, and with carbon dioxide, alkylcarbamate alkylamine salt or 1,3-dialkylurea (JP-A 57-98268); a reaction of ethylene glycol with carbon dioxide and monomethylamine at an elevated temperature and a higher pressure (JP-A 59-155364); and a reaction of ethylene carbonate with monoalkylamine (WO96/02516). These may be promising DMI preparation processes because they are a one-step reaction and the starting materials, i.e., N-alkylmonoethanolamine, ethylene glycol and ethylene carbonate, can be readily prepared from ethylene oxide with minimal byproducts. Based on our findings, however, a large amount of black solid is formed in these processes, which may block up a line during recycling all or a part of high boiling products into a reactor after collection of 1,3-dialkyl-2-imidazolidinone. These processes are, therefore, industrially impractical and thus have not been industrialized.
In addition, 1,3-dialkyl-2-imidazolidinones prepared according to these processes contain not a little amount of N-alkylformamide as an impurity, and thus are not suitable for use as a solvent.
Furthermore, commercially available DMI contains 1-methoxymethyl-3-methyl-2-imidazolidinone as an impurity, which may cause problems such as a reduced yield and a formation of byproducts when used as a reaction solvent or a polymerization solvent.
SUMMARY OF THE INVENTION
Thus, an object of this invention is to provide a process for manufacturing 1,3-dialkyl-2-imidazolidinones in a direct one-step reaction from industrially available alkylene carbonate, N-alkylmonoethanolamine or 1,2-diol, which can minimize forming solid materials and be readily conducted in an industrial large-scale production with a higher yield and less byproducts; as well as 1,3-dialkyl-2-imidazolidinone containing a minimal amount of 1-methoxymethyl-3-methyl-2-imidazolidinone according to the process.
We have intensely investigated a method for minimizing 1-alkoxyalkyl-3-alkyl-2-imidazolidinones as an impurity in 1,3-dialkyl-2-imidazolidinones and reducing formation of solid during the reaction, and have finally found that solid formation may be reduced, 1,3-dialkyl-2-imidazolidinones may be produced in a higher yield and 1-alkoxyalkyl-3-alkyl-2-imidazolidinones can be minimized by heating alkylene carbonate, N-alkylmonoethanolamine or ethylene glycol with monoalkylamine and carbon dioxide, alkylcarbamate alkylamine salt, and/or 1,3-dialkylurea at 50° C. or higher in a reactor whose area in contact with at least part of the reactants and/or products is made of (I) a metal comprising titanium or zirconium and/or an oxide thereof or (II) inorganic glasses.
Specifically, this invention provides;
(A) 1,3-dialkyl-2-imidazolidinones represented by general formula (1):
wherein R
1
is hydrogen or C
1
-C
6
alkyl and R
2
is C
1
-C
6
alkyl, containing 50 ppm by weight or less of 1-alkoxyalkyl-3-alkyl-2-imidazolidinones represented by general formula (2):
wherein R
1
and R
2
are as defined above; and R
3
is C
1
-C
6
alkylene; or general formula (3):
wherein R
1
, R
2
and R
3
are as defined above;
(B) 1,3-dimethyl-2-imidazolidinone containing 50 ppm by weight or less of 1-methoxymethyl-3-methyl-2-imidazolidinone;
(C) 1,3-dialkyl-2-imidazolidinones described in (A) containing 0.5 wt % or less of N-alkylformamide represented by general formula (4):
R
2
NHCHO (4)
wherein R
2
is as defined above;
(D) 1,3-dimethyl-2-imidazolidinone described in (B) containing 0.5 wt % or less of N-methylformamide;
(E) a process for manufacturing 1,3-dialkyl-2-imidazolidinones described in (A) or (C), comprising heating at 50° C. or higher alkylene carbonate represented by general formula (5):
wherein R
1
is as defined above, with monoalkylamine represented by general formula (6):
R
2
NH
2
(6)
wherein R
2
is as defined above; alkylcarbamate alkylamine salt represented by general formula (7):
R
2
NHCOOH.R
2
NH
2
(7)
wherein R
2
is as defined above; and/or 1,3-dialkylurea represented by general formula (8):
R
2
NHCONHR
2
(8)
wherein R
2
is as defined above; in a reactor whose area in contact with at least part of the reactants and/or products is made of (I) a metal comprising titanium or zirconium and/or an oxide thereof or (II) inorganic glasses;
(F) a process described in (E) where the reaction is conducted in the presence of carbon dioxide;
(G) a process for manufacturing 1,3-dialkyl-2-imidazolidinones described in (A) or (C), comprising heating at 50° C. or higher N-alkylmonoethanolamine represented by general formula (9):
wherein R
1
and R
2
are as defined above; with
i) monoalkylamine represented by general formula (6) and carbon dioxide,
ii) alkylcarbamate alkylamine salt represented by general formula (7), and/or
iii) 1,3-dialkylurea represented by general formula (8), in a reactor whose area in contact with at least part of the reactants and/or products is made of (I) a metal comprising titanium or zirconium and/or an oxide thereof or (II) inorganic glasses;
(H) a process for manufacturing 1,3-dialkyl-2-imida
Katou Takazou
Matsuba Katsuhiko
Nakagawa Shin-ichi
Yamamoto Yoshihiro
Burns Doane , Swecker, Mathis LLP
Higel Floyd D
Mitsui Chemicals Inc.
Saeed Kamal
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