Abstract: In producing alkanolamines by use of a microporous material as a catalyst, the difficulty in industrially performing the production because of the short lifetime of the catalyst is resolved. A process of regenerating the catalyst by removing an organic substance deposited on the catalyst by means of decomposing and/or extracting the substance is introduced, and thereby steady production is carried out substantially over the long term by switching the reaction and the regenerating processes.

Abstract: An unsaturated aldehyde expressed by Formula (I) below is hydrated with a solution in the presence of a carboxylic-acid-based resin having of a structure expressed by Formula (II) below: ##STR1## where R represents one of a hydrogen atom and a hydrocarbon group having up to five carbons; ##STR2## where R.sub.1 and R.sub.2 respectively represent a hydrogen atom, hydrocarbon group having up to five carbons, or --(--CH.sub.2 --).sub.p1 --X group, p.sub.1, k.sub.1, and m.sub.1 respectively represent an integer from zero to six, n.sub.1 represents an integer from one to six, Y.sub.1 represents --O--, --S--, or --NR.sub.3 --, R.sub.3 represents a hydrogen atom or hydrocarbon group having up to five carbons, and X represents a carboxylic-acid-based resin main body. Using a heat-resistant catalyst as above makest it possible to increase the reaction rate by heating, and produce hydroxyalkanal at high selectivity and yield out of an industrially advantageous high-concentration unsaturated aldehyde solution.

Abstract: A process of producing hydroxyalkanal comprises a step of hydrating a raw material, namely, an unsaturated aldehyde, in an aqueous solution in the presence of a lead-carrying heterogeneous acid catalyst promoting the hydration reaction. According to the above method, the lead-carrying heterogeneous acid catalyst curbs the consecutive reaction of the reaction product, namely, hydroxyalkanal. Thus, hydroxyalkanal can be produced with high selectivity at high yield out of a high-concentration unsaturated aldehyde solution. Moreover, the catalyst can be used repetitively for a considerable period of continuous use in a stable manner, thereby further improving the yield of hydroxyalkanal.

Abstract: In a process of producing hydroxyalkanal, a raw material, namely, an unsaturated aldehyde, is hydrated with a solution in the presence of a catalyst, and alcohol is added to the solution. A adding amount of the alcohol with respect to the unsaturated aldehyde is preferably in a range between 0.001 percent by weight and 10 percent by weight. According to this process, a consecutive reaction (side reaction) of a reaction product, namely, hydroxyalkanal, is curbed by the alcohol added to the solution, thereby making it possible to produce hydroxyalkanal at high selectivity out of a high-density unsaturated aldehyde solution. Therefore, the above process can trigger a reaction of an industrially advantageous unsaturated aldehyde solution, and thus improves the yield of hydroxyalkanal.