^ ^ ^ ^ I ^ ^ ^ ^ ^ ^ II ^ II ^ II ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ I ^ European Patent Office Office europeen des brevets EP 0 763 518 A1 EUROPEAN PATENT APPLICATION (43) Date of publication: (51) |nt CI C07C 67/62, C07C 69/732, 19.03.1997 Bulletin 1997/12 C07C 255/1 5, C07C 253/32 (21) Application number: 96306611.3 (22) Date of filing: 12.09.1996 (84) Designated Contracting States: • Makino, Mitsuaki DE FR GB Himeji-shi, Hyogo 671-12 (JP) • Kita, Yuichi (30) Priority: 14.09.1995 J P 237440/95 Akashi-shi, Hyogo 673 (JP) (71) Applicant: NIPPON SHOKUBAI CO., LTD. (74) Representative: West, Alan Harry et al Chuo-ku, Osaka-shi, Osaka-fu 541 (JP) R.G.C. Jenkins & Co. 26 Caxton Street (72) Inventors: London SW1H 0RJ (GB) • Nakagawa, Koichi Himeji-shi, Hyogo 672 (JP) (54) Stabilization method of vinyl compound with hydroxy group and composition containing such vinyl compound (57) A vinyl compound having an hydroxy group is by mixing it with minor amounts of primary antioxidant stabilised against being denatured during storage, together with an alcohol and/or water, and/or with an or- transportation and use while maintaining its reactivity, ganic acid. < 00 lo CO CO o a. LU Printed by Jouve, 75001 PARIS (FR) EP0 763 518 A1 Description The present invention generally relates to a stabilization method of a vinyl compound with hydroxy group and a composition containing such vinyl compound, and more particularly relates to a stabilization method which offers an 5 improved stability of the vinyl compound with hydroxy group by preventing a vinyl compound with hydroxy group from being denatured on storage, transportation, manufacturing process, etc., and to a composition containing the vinyl compound of an improved stability. The vinyl compound with hydroxy group having an active hydroxyl group is a useful compound in a variety of fields, for example, as a monomer for use in preparing a polymer of high heat-resistance; a raw material for optical materials 10 of high refractive index; raw materials for various chemical products, such as a coating agent, an adhesive agent, a builder for detergent, an improving agent for wood; an intermediate of medical supplies, such as an anticancer drug, an antivirus drug, etc. A vinyl compound with hydroxy group is a monomer having an active hydroxyl group, and it is generally known that such vinyl compound is heat-unstable. For this undesirable feature, the vinyl compound with hydroxy group gen- 15 erates an oligomer thereof when heating it to or above room temperature, and further a thermal polymerization of the vinyl compound with hydroxy group is apt to occur only by heating it above room temperature. With a further application of heat, a glassy colorless transparent high polymer compound (polymer) is generated. Especially, a high purity vinyl compound with hydroxy group may cause a polymerization reaction based on a reactivity of the hydroxyl group even on its storage at room temperature, and generate impurities of high boiling point. Namely, if the vinyl compound with 20 hydroxy group is stored for a long period of time at room temperature, impurities are generated which gradually lowers the quality of the vinyl compound. For example, intensive studies have been made by the inventors of the present invention on the stability of a- (hydroxymethyl) acrylic esters. As a result, they have found that the a-(hydroxymethyl) acrylic esters have a highly active methylol group and a double bond. Therefore, when the a-(hydroxymethyl) acrylic esters are stored for a long 25 period of time at room temperature, impurities that assumed to be generated by reacting an oligomer of a-(hydroxyme- thyl) acrylic esters and a methylol group to a double bond by Michael additive reaction, impurities of unknown structure, etc., are gradually generated. As a result, they have found that when the a-(hydroxymethyl)alkyl acrylate is stored for a long period of time at room temperature, impurities are generated which results in lower purity. On the other hand, in order to achieve an improved stability of a heat-unstable compound, conventionally, a po- 30 lymerization inhibitor such as p-methoxyphenol, hydroquinone, phenothiazine, p-t-butylcatechol, etc., is added to the compound as a stabilizer. However, the described stabilization method of the heat-unstable compound by adding the stabilizer has the fol- lowing drawbacks. That is, the main purpose of adding such stabilizer is to improve the heat-stability of the vinyl group. Therefore, although the stabilization effect is fully anticipated for the compound having a vinyl group, it is not effective 35 for the compound having other functional group. Namely, the effect of the described stabilizer greatly varies depending on the structure of the compound. For this reason, in the described conventional stabilization method, even if the stabilizer is added in a large amount, it is not necessarily that the sufficient stabilization effect for the vinyl compound with hydroxy group can be expected. Besides, if the stabilizer is added in a large amount, the reactivity of the vinyl compound with hydroxy group cannot be maintained, and this have led to the need for development of a desirable 40 stabilization method for the vinyl compound with hydroxy group. On the other hand, if a large amount of hydroquinone is added as a stabilizer, a compound would be colored over time. The first object of the present invention is to provide a stabilization method for a vinyl compound with hydroxy group by preventing it from being denatured on storage, transportation, manufacturing process, etc., while maintaining its reactivity. 45 The second object of the present invention is to provide a composition containing a vinyl compound with hydroxy group of an improved stability. In order to achieve the above object, intensive studies have been made by the inventors of the present invention on the stabilization method for the vinyl compound with hydroxy group, and a composition containing the vinyl compound with hydroxy group of an improved stability. As a result, they have found that with a coexistence of a vinyl compound so with hydroxy group, the primary antioxidant, alcohol and/or water, or by a coexistence of the vinyl compound with hydroxy group, the primary antioxidant and the organic acid, the vinyl compound with hydroxyl group can be prevented from being denatured on storage, transportation, manufacturing process, etc., while maintaining its reactivity, thereby achieving an improved stability of the vinyl compound with hydroxy group to complete the present invention. Namely, in order to achieve the first object of the present invention, the stabilization method of the vinyl compound 55 with hydroxy group in accordance with the present invention is characterized by including the step of: (a) coexisting a vinyl compound with hydroxy group of formula (1), a primary antioxidant, alcohol and/or water, 2 EP0 763 518 A1 CH2 = C - CH-OH ... (1) R wherein R is a hydrogen atom or an organic residue, X is a -CN group, a -CORg group or a -COOR0 group, and R0 is a hydrogen atom or an organic residue. 10 Another stabilization method of vinyl compound with hydroxy group of the present invention is characterized by including the step of coexisting the vinyl compound with hydroxy group of formula (1 ), the primary antioxidant, and the organic acid. According to the stabilization method of the present invention, the vinyl compound with hydroxy group can be prevented from being denatured on storage, transportation and manufacturing process while maintaining its reactivity. is As a result, an improved stability of the vinyl compound with hydroxy group can be achieved. Another benefit of the stabilization method of the present invention lies in that it does not adversely affect the reactivity of the vinyl compound with hydroxy group which eliminates the need of refining the vinyl compound with hydroxy group. For the described beneficial features, the stabilization method of the present invention is industrially useful. In order to achieve the second object, the composition containing the vinyl compound with hydroxy group of the 20 present invention is characterized by including the vinyl compound with hydroxy group of formula (1), the primary antioxidant, and alcohol and/or water. Another composition including the vinyl compound with hydroxy group of the present invention is characterized by including the vinyl compound with hydroxy group of formula (1 ), the primary antioxidant, and organic acid. The vinyl compound with hydroxy group of the described structure offers an improved stability. Moreover, when 25 manufacturing derivatives or polymers of the vinyl compound with hydroxy group, the described composition permits the side reaction of the vinyl compound with hydroxy group to be suppressed. Moreover, as the described stabilization method does not adversely affect the reactively of the vinyl compound with hydroxy group, the need of the refining process can be omitted. For the described beneficial features, the stabilization method of the present invention is industrially useful. 30 For a fuller understanding of the nature and advantages of the invention, reference should be made to the ensuing detailed description taken in conjunction with the accompanying drawings. The present invention will now be described in further detail. A vinyl compound with a hydroxyl group represented by the formula (1 ) of the present invention is easily obtained by a reaction of a vinyl compound of the formula (2) and an aldehyde compound, 35 CH2 = C - H ... ( 2 ) wherein X is a -CN group, a -COR0 group, or a -COOR0 group, and R0 is a hydrogen atom or an organic residue. The method of manufacturing a vinyl compound with hydroxy group is not particularly limited. The vinyl compound of the formula (2) has a substituent X of a -CN group, a -COR0 group or a -COOR0 group, 45 and a substituent R0 of a hydrogen atom or an organic residue.