In a method of producing a dialdehyde monoacetal(s) (III) from dialdehyde(s) (I) and diol(s) (II), the present invention provides a method comprising a first step wherein said dialdehyde(s) (I) and said diol(s) (II) are reacted to produce dialdehyde bisacetal(s) (IV), the amount by mole of said diol(s) (II) being at least twice the amount by mole of said dialdehyde (I) and a second step wherein said dialdehyde bisacetal(s) (IV) is reacted with said dialdehyde (I). The present invention also provides a method of producing a glutaraldehyde monoacetal via reacting 2-Y-3, 4-dihydro-2H-pyran or a ring-substituted derivative thereof with diol. This method comprises a second step reaction wherein glutaraldehyde (iv) which is one of the by-products of the first step reaction is reacted with glutaraldehyde bisacetal (v) which is another by-product of said first reaction. According to the present invention, in the above-mentioned method of producing a glutaraldehyde monoacetal (iii), after the end of the first step reaction, the crude reaction solution is heated at a temperature of from 100.degree. C. to 200.degree. C. to produce the glutaraldehyde monoacetal (iii) from the by-products, low boiling-point components produced from the substituant group Y being removed via distillation.
The invention relates to a process for obtaining a pure aliphatic dialdehyde monoacetal by reaction of the corresponding aliphatic dialdehyde or a precursor of the corresponding aliphatic dialdehyde with one or more aliphatic mono- or polyhydric alcohols while distillatively removing water to obtain a reaction mixture which is separated distillatively, which comprises carrying out the distillative separation continuously in a dividing wall column to obtain pure aliphatic dialdehyde monoacetal as a sidestream from the dividing wall column, or in two distillation columns to obtain crude aliphatic dialdehyde monoacetal as a sidestream in the first distillation column, feed the crude aliphatic dialdehyde monoacetal to the second distillation column and obtain pure aliphatic dialdehyde monoacetal as the sidestream from the second distillation column.
A process for the preparation of aqueous formulations, and aqueous formulations so prepared, the process comprising heating at least one cyclic compound of the formula I ##STR00001## in the presence of water and of an acidic catalyst and, during or after the heating, H--X--R.sup.3 is at least partially separated off, where, in formula I, X is selected from oxygen, sulfur and N--R.sup.6, R.sup.1-R.sup.6 are as defined, and n is an integer from 1 to 4.
