2912.50 - Cyclic polymers of aldehydes:

This HTS category, 2912.50, specifically encompasses cyclic polymers derived from aldehydes. These are compounds where multiple aldehyde molecules have chemically bonded together in a ring structure. The defining characteristic is the polymeric nature and the cyclic arrangement of the aldehyde units, distinguishing them from simple aldehydes or acyclic polymers.

Within Chapter 29, which deals with organic chemicals, this category stands apart from other aldehyde-related classifications. It is distinct from acyclic aldehydes (2912.1x), cyclic aldehydes without polymerization (2912.2x), and aldehyde alcohols, ethers, and phenols (2912.3x), all of which feature single aldehyde groups or different functional arrangements. Furthermore, it is differentiated from paraformaldehyde (2912.60), which is a linear polymer of formaldehyde.

The subcategories under 2912.50 provide a breakdown based on specific types and general classifications. 2912.50.10.00 covers Metaldehyde, a common cyclic polymer of acetaldehyde with specific applications. The 2912.50.50.00 category is a residual category for all other cyclic aldehyde polymers not otherwise specified, allowing for the classification of a diverse range of such compounds.