Material guide: Triplal — an 8-hour green aldehyde that becomes a 268-hour one once you attach an amine

About a 5 minute read.

The short version

• Name: the database's official name is 2,4-ivy carbaldehyde, its head_synonym is triplal (IFF), CAS 68039-49-6
• C9H14O, molecular weight 138.21, 54 suppliers
• Odour type green; odour: green, aldehydic, leafy, cortex, tart, floral, peely
• Strength high (rank 3); the evaluation field says outright to smell it at 10% or less
• Substantivity only 8 hours, vapour pressure 0.578 mmHg. This is a top note
• The corpus uses three names, merging to 90 formulas at a median dose of 0.60%
• The database also holds two of its Schiff bases: 268 hours and 400 hours
• Store under nitrogen, with a shelf life of only 12 months

The name first, because this material is the example

Last round I measured which name normalisation pays, and triplal was in that table: 63 occurrences, shut out by one (IFF) bracket.

The corpus's three spellings:

Corpus writes	Count
triplal	63
2,4-ivy carbaldehyde	22
triplal (iff)	5

Merged, 90 formulas. The database's name field is the chemical name and its head_synonym is triplal (IFF); strip the bracket and the first two both match.

(Incidentally: the corpus also holds 3,5-ivy carbaldehyde (4) and tricyclal (11), which are different isomers and cannot be merged. cyclal c (20) is something else again.)

It is a loud top note

Field	Value
Vapour pressure @25 °C	0.578 mmHg
Substantivity	8 hours
Strength rank	3 (high)
Recommended evaluation	10% or less
Median dose across 90 formulas	0.60% (quartiles 0.31–1.40%)

That 0.60% sits low. The overall median I measured is 2.11%, and the median for strength rank 3 is 0.76%. It is used more sparingly than its own rank.

The odor_descriptions entry was evaluated at 10% in dipropylene glycol rather than neat, which is exactly what the evaluation concentration field is for: telling you how far to dilute before the shape appears.

One evaluator's description is blunt:

Green, leafy, floral, powerful.

Attach one amine and 8 hours becomes 268

This is the genuinely interesting part. The database holds two more records, both derivatives of this same aldehyde:

Record	Formula	MW	Vapour pressure @25 °C	Substantivity	Suppliers
#20883 triplal	C9H14O	138.21	0.578	8 h	54
#20876 + methyl anthranilate Schiff base	C17H21NO2	271.36	(no value)	268 h	9
#40465 + ethyl anthranilate Schiff base	C18H25NO2	287.40	0.000001	400 h	0

Same aldehyde, one amine attached, and substantivity goes from 8 hours to 268.

Chemically this is a Schiff base: the aldehyde's carbonyl condenses with a primary amine to give an imine, losing one water. What matters is that the reaction is reversible. In the presence of water — skin, a detergent, a lotion — the Schiff base hydrolyses slowly back to the aldehyde and the amine, releasing odour as it comes apart.

And it releases two smells: the green aldehyde, and the anthranilate, which is itself a grape-and-neroli fragrance material.

Two 2022 papers deal with this directly. Palágyi and colleagues built cyclodextrin-based Schiff base pro-fragrances and measured their release in Beilstein J Org Chem (PMID 36247979), and Nicastro and colleagues studied the controlled hydrolysis of odorant Schiff bases in low-molecular-weight gels in Int J Mol Sci (PMID 35328526).

The corpus shows it is not theoretical either. Beyond triplal's two:

• hydroxycitronellal / methyl anthranilate schiff's base (6 formulas)
• schiff base (hydroxycitronellal/anthranilate) (2)
• alpha-amyl cinnamaldehyde / methyl anthranilate schiff's base (1)

Hydroxycitronellal uses the same trick.

Here is where one of my own numbers gives out

Last round I computed roughly 5.85x substantivity per decade of vapour pressure.

From triplal (0.578) to the ethyl anthranilate Schiff base (0.000001) is 5.76 decades. At 5.85x per decade, 8 hours would become twenty-six thousand times longer: two hundred thousand hours.

The registered value is 400.

That is not the data being wrong; it is my relationship extrapolated past where it holds. The 5.85x came from fitting 12 buckets whose median vapour pressures span about three decades. Extrapolating nearly six decades produces nonsense. And 400 is also that field's ceiling, so this record runs into two limits at once.

The practical reading: Schiff bases really do last much longer, but do not compute ratios from the numbers 8, 268 and 400.

Storage: under nitrogen, twelve months

The storage field says:

Store in cool, dry place in tightly sealed containers, protected from heat and light. Store under nitrogen.

"Store under nitrogen" is uncommon in this database. The reason is direct: it is an aldehyde. Aldehydes oxidise to carboxylic acids in air, and 2,4-ivy carbaldehyde also carries a ring double bond, putting two oxidisable positions in one molecule.

Its shelf_life reads 12 months, where most materials read 24.

If you buy a bottle, it will turn faster than you expect once opened, and what it turns into smells sour.

What it appears alongside

Most frequent company across the 90 formulas:

Material	Count		Material	Count
hedione	32		benzyl acetate	23
linalool	31		phenethyl alcohol	23
dipg (solvent)	30		citronellol	20
dihydromyrcenol	24		gamma-undecalactone	18
lilial	24		alpha-hexyl cinnamaldehyde	17

Hedione, dihydromyrcenol, Lilial: the roster of a modern fresh floral. Its job in there is the one spoonful of just-picked green, kept down at 0.60%.

What this doesn't establish

• I measured none of these substantivities. The 8, 268 and 400 are all field values, and I wrote only last round that 400 is a bucket label rather than a measurement.
• The Schiff base release mechanism comes from the papers, not from this database. Both 2022 studies work on cyclodextrin scaffolds and gel systems rather than measuring these two materials.
• #40465 has a supplier count of 0. That means this database holds no supplier records for it, not that it is unavailable. It also means its field values are less likely to have been checked.
• I did not verify the occurrence field's not found in nature.
• The notes field reads None found, which is a placeholder.
• The three-name merge excludes 3,5-ivy carbaldehyde and tricyclal, which are different isomers. I did not establish how cyclal c relates to this material; the evaluation field mentions it, but that may be an evaluator's point of comparison.