4-methylene-1,3-dioxolanes having functional groups

Details 4-methylene-1,3-dioxolanes having functional groups 4-methylene-1,3-dioxolanes having functional groups

2000-10-05

2002-05-14

Solola, T. A. (Department: 1626)

Organic compounds -- part of the class 532-570 series

Organic compounds

Heterocyclic carbon compounds containing a hetero ring...

C549S453000, C549S454000

Reexamination Certificate

active

06388104

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to novel 4-methylene-1,3-dioxolanes having functional groups, which is easy applicable to UV curable inks, coatings as a reactive thinner or a crosslinking agent, to a process for the production thereof and to the intermediates used in this process.
BACKGROUND OF THE INVENTION
Commercially available vinyl ethers are based on base-catalysed addition of acetylene onto alcohols under pressure. The resultant compounds contain the structural element H
2
C═CH—OR and have been used industrially for many years. These compounds have attracted particular attention in cationic and photocationic polymerisation as, due to their electron-rich double bond, they are generally highly reactive compounds.
However, users always complain that volatile, strong-smelling components are formed during crosslinking which, at elevated concentration, are irritant and thus problematic on occupational hygiene grounds. Comprehensive precautions are thus required on occupational safety and health protection grounds which not only entail considerable costs for users, but also put up the prices of their products.
It has been known for some time that one of the principal components of these unwanted volatile secondary products is acetaldehyde, which is produced in a secondary reaction of vinyl ether with ambient moisture. T. Moriguchi et al.,
Macromolecules
1995, 28, 4334-4339, have reported a possible reaction pathway.
Various approaches to solving this problem have been discussed for some time. From an economic standpoint, the most promising approach would seem to be to rearrange readily available allyl ethers to yield isopropenyl ethers on noble metal catalysts (J. V. Crivello, U.S. Pat. No. 5,486,545, Jan. 23, 1996). However, this approach overlooks the fact that, during cationic and photocationic polymerisation, isopropenyl ethers may also enter into a secondary reaction with water, analogous to that of the commercial vinyl ethers, resulting in the formation of propionaldehyde. Isopropenyl ethers are thus also incapable of satisfying the requirement for emission-free crosslinking. Open-chain vinyl ethers are in principle incapable of achieving this as it is always possible for them to give rise to volatile cleavage products in the presence of moisture.
Cyclic vinyl ethers, on the other hand, such as for example 2,3-dihydrofurans and 2,3-dihydropyrans, are virtually ideal vinyl ethers. While they may indeed also enter into secondary reactions with water during photocationic reactions, no volatile cleavage products are formed, as the irritant aldehyde component remains firmly attached to the molecule. However, these heterocyclic compounds, if they are to have a suitable degree of substitution which permits further conversion, are complex to synthesise, such that relatively large quantities have not hitherto been industrially available at reasonable cost.
In contrast, the class of 4-methylene-1,3-dioxolanes is much more straightforwardly available.
U.S. Pat. No. 2,445,733, Jul. 21, 1945, describes the first attempts to crosslink 4-methylene-1,3-dioxolanes. However, depending upon the metal ion, the Friedel-Crafts catalysts which are used give rise to reddish-brown coloured masses, but not to solvent-resistant networks. Using an alcoholic solution of zinc chloride (H. Orth,
Angew. Chem.
1952, 64, 544-553) brought about some improvement, but the polymerisations performed were markedly exothermic and sometimes proceeded explosively on addition of the catalyst. One positive feature which may be noted, however, is that the resultant networks have considerable surface hardness and, consequently, good workability.
It has recently been found that 4-methylene-1,3-dioxolanes are also photocationically active. K. D. Belfield and F. B. Abdelrazzaq,
Macromolecules
1997, 30, 6985-88 accordingly describe photocationic crosslinking of 2,2′-(1,4-phenylene)bis(4-methylene-1,3-dioxolane) with 2-phenyl-4-methylene-1,3-dioxolane. Both monomers are, however, of an aromatic nature, i.e. they have aromatic substituents in position 2. It is, however, now known that 4-methylene-1,3-dioxolanes which have a 2,2-diphenyl- or 2-phenyl-2-alkyl substitution polymerise with elimination of the ketone component (R. S. Davidson, G. J. Howgate,
J. Photochem. Photobiol. A.,
1997, 109, 185-193 and Y. Hiraguri, T. Endo,
J. Polym. Sci. Part A: Polym. Chem.
1989, 27, 4403-4411), i.e. eliminating components of a greater or lesser degree of volatility. As a result, the requirement for emission-free crosslinking cannot be met.
It has now surprisingly been found that purely aliphatically substituted 4-methylene-1,3-dioxolanes differ fundamentally from the aromatic derivatives thereof and may be crosslinked under photocationic conditions without emissions. This is confirmed by findings in the scientific literature: 2-isopropenyl-4-methylene-1,3-dioxolane yields a linear polymer having ketone groups, wherein polymerisation proceeds exclusively by ring-opening (J. Park, N. Kihara, T. Ikeda, T. Endo,
J. Polym. Sci. Part A: Polym. Chem.
1993, 31, 1083-1085).
The possibility of designing crosslinking systems based on 4-methylene-1,3-dioxolanes has hitherto more or less been restricted to the industrial availability of dialdehydes and diketones and the tetraacetals and tetraketals thereof. The lack of suitably substituted 4-methylene-1,3-dioxolanes is thus noticeably restricting the potential possibilities of this class of monomers.
SUMMARY OF THE INVENTION
The object of the invention is to provide novel 4-methylene-1,3-dioxolanes which have at least one further functional group, such as for example an OH group or ester group, such that further conversions are individually possible. These 4-methylene-1,3-dioxolanes should satisfy the following requirements:
(i) no elimination of acetaldehyde or propionaldehyde during crosslinking,
(ii) ready availability by means of industrially straightforward operations,
(iii) production from low cost basic substances available in industrial quantities,
(iv) no use of costly noble metal catalysts or catalyst systems which are difficult to regenerate,
(v) activity equal to or greater than commercial vinyl ethers,
(vi) low vapour pressure so that there is virtually no odour nuisance.
The present invention provides 4-methylene-1,3-dioxolanes of the general formula I
in which R1 denotes hydrogen or alkyl, X denotes a single bond, C
1
-C
18
alkylene, cycloalkylene, arylalkylene, —CH
2
(OCH
2
CH
2
)
n
— or —CH
2
(OCH(CH
3
)CH
2
)
n
—, in which n is an integer from 1 to 100, and Z means a functional group selected from among —OH, —COOR′ or —OCOR′, in which R′ denotes hydrogen or C
1
-C
8
alkyl.
DETAILED DESCRIPTION OF THE INVENTION
The 4-methylene-1,3-dioxolanes according to the invention, which may be considered 1,1-disubstituted vinyl ethers, satisfy the above stated conditions (i) to (vi). The reactivity of vinyl ethers is known approximately to follow the series R
1
R
2
C═CH—O—R<R
1
CH═CH—O—R<CH
2
═CH—O—R<CH
2
═CR
3
—O—R, i.e. the 1,1-disubstituted vinyl ethers are generally the most reactive if their substituents are not too sterically demanding (O. Nuyken, R. B. Raether, C. E. Spindler,
Macromol. Chem. Phys.
1988, 199, 191-196).
The invention is based on the surprising observation that, despite simultaneously having an allyl structure (allyl compounds being known to have a slight tendency to polymerise), the 4-methylene-1,3-dioxolanes represented by the general formula I exhibit the elevated reactivity of 1,1-disubstituted vinyl ethers in photocationic reactions.
There follow some definitions of terms which are used in this document:
Unless otherwise stated, the term “alkyl” denotes a monovalent alkane residue of the general formula C
n
H
2n+1
, in which n denotes the number of carbon atoms and ranges from 1 to 18, preferably from 1 to 6.
The alkyl residues may be linear or branched.
Examples of such alkyl residues are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t.-butyl etc . . .
The term “a

Affiliated with

Also associated with

Rating

4-methylene-1,3-dioxolanes having functional groups does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with 4-methylene-1,3-dioxolanes having functional groups, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and 4-methylene-1,3-dioxolanes having functional groups will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2875909