Isobutylidenediurea
Isobutylidenediurea is an organic compound with the formula 2CHCH2. It is a derivative of urea, which itself is highly soluble in water, but IBDU is not. It functions as a controlled-release fertiliser owing to its low solubility, which limits the rate of its hydrolysis to urea, which is a fast-acting fertiliser.
It is produced by the condensation reaction of isobutyraldehyde and two equivalents of urea:
The controlled-release process is the reverse of the above reaction, which only occurs after the IBDU dissolves.