反应详情

The polyvinyl acetal resins of the invention include 4-hydroxybutanal as an aldehyde component. Pure 4-hydroxybutanal is suitable for the invention, but is obtained only by laborious and costly methods. An economical source of 4-hydroxybutanal is an aqueous aldehyde stream produced commercially when allyl alcohol is hydroformylated in the presence of a rhodium catalyst. The aqueous stream, which typically contains about 5-20 wt. % aldehydes, is obtained by extracting the hydroformylation reaction mixture with water. The aldehyde mixture contains about a 7:1 molar ratio of 4-hydroxybutanal and 3-hydroxy-2-methylpropanal. In the commercial process, the aldehyde stream is hydrogenated to give 1,4-butanediol and 2-methyl-1,3-propanediol. However, the aqueous aldehyde stream is alternatively and advantageously used for the process and compositions of the present invention. The aqueous aldehyde solution used for the invention can have any desired aldehyde concentration.

1. extractionby extracting
2. customthe hydroformylation reaction mixture with water