Vanillin

Ball-and-stick Stick Space-filling

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19 atoms, 19 bonds.

IUPAC name: 4-hydroxy-3-methoxybenzaldehyde
Molar mass: 152.149(21) g/mol
Atoms: 19
SMILES: COC1=C(C=CC(=C1)C=O)O
InChIKey: MWOOGOJBHIARFG-UHFFFAOYSA-N
PubChem CID: 1183

Made of

Structural formula of vanillin. Each unlabelled corner is a carbon atom, and the four hydrogens on carbon are not drawn. It shows which atoms are joined to which, not the shape. The model above shows the shape.

One part of vanillin equals 400 parts of vanilla pods, the Hazardous Substances Data Bank (HSDB) records. The pure compound forms white or slightly yellow needles or a crystalline powder. JECFA, the joint expert committee on food additives run by FAO and WHO, describes its odour as sweet, creamy and vanilla-like. Its IUPAC name, 4-hydroxy-3-methoxybenzaldehyde, spells out the three groups hung on its benzene ring. Built from carbon, hydrogen and oxygen, it has a molar mass of 152.15 g/mol.

Only about 1.0 g dissolves in 100 mL of water at 25 °C, yet vanillin is very soluble in ethanol and acetone. HSDB gives a pKa, a measure of acid strength where lower means stronger, of 7.4, so vanillin is a weak acid. Its solutions are acid to litmus, and it dissolves freely in alkali hydroxide solutions. Moist air slowly oxidises it and light affects it, according to HSDB.

Structure and bonding

The viewer draws 19 atoms and 19 bonds: eight carbons, eight hydrogens and three oxygens. Six carbons close a hexagon, and from one corner an aldehyde group, CHO, points outward with its oxygen double-bonded. Two corners further round, a methoxy group, OCH₃, ties a methyl carbon to the ring through an oxygen; the next corner carries a hydroxyl group, OH. With Labels on, each atom prints C, H or O, and the three oxygens show up in three different settings.

Ball-and-stick draws the ring as alternating single and double bonds. Chem1 treats a benzene ring like this one as a resonance hybrid, a blend of both double-bond patterns. Its pi electrons, each double bond’s second pair, spread above and below the plane. The model’s measurements fit: all six ring bonds are 1.395 Å long whichever order is drawn, while the single bond out to the aldehyde carbon is 1.454 Å.

Seen edge-on, all eleven carbon and oxygen atoms of the conformer, PubChem’s computed 3D shape, lie in one plane. In Space-filling the overlapping spheres merge into a thin slab. Stick thins the frame to rods, leaving the angles of about 120° around each ring carbon easy to follow.

Where it turns up

Inside the vanilla bean, HSDB records, vanillin is stored bound to a sugar as vanillin-4-beta-D-glucoside. Vanilla bean extract is the major commercial source of natural vanillin, although the compound also occurs in a wide range of plants and foods, orchids among them. It has been reported in Humulus lupulus and Ficus erecta var. beecheyana as well.

Vanillin flavours confectionery, beverages, foods and animal feeds, according to HSDB. Its intended uses under the US Food and Drug Administration’s (FDA) GRAS scheme, for substances generally recognised as safe, include baked goods, chewing gum, frostings and puddings. Vanillin scents cosmetics too, and California’s Safe Cosmetics Program counts 6069 products reporting it. Medicines also take it as a flavour, a pharmaceutical aid in HSDB’s terms.

Why it matters

Bulk vanillin is synthesised from lignin, left in the sulfite wastes of the cellulose and paper industries, or from guaiacol, according to HSDB. US Environmental Protection Agency (EPA) figures put its aggregated US product volume for 2023 at 10 million to under 25 million pounds.

Techniques for natural vanillin start from precursors such as eugenol or ferulic acid. On HSDB’s account microbial biotransformation, or fermentation, appears the most promising of them for producing large quantities of high-quality natural vanillin. Shifts in the carbon-13 to carbon-12 ratio of a natural vanilla extract can reveal artificial vanillin mixed into it, according to IUPAC text in PubChem’s carbon record.

Vanillin is a chemical starting point as well as a flavour. Its single largest use, according to HSDB, is the manufacture of methyldopa, a drug that lowers blood pressure. It is also a source of L-dopa and a reagent for synthesis. Haz-Map, an occupational-health database, records further uses as a fuel additive, odour agent and anti-UV agent.

Properties

Properties of vanillin Molar mass summed from IUPAC/CIAAW 2024 standard atomic weights; formula, atom and bond counts and PubChem's molecular weight from PubChem CID 1183.
Property	Value	Unit	Source
Molecular formula (Hill order)	C₈H₈O₃
Molar mass	152.149(21) g/mol	g/mol	IUPAC/CIAAW 2024
Carbon atoms	8
Hydrogen atoms	8
Oxygen atoms	3
Bonds	19
Single bonds	15
Double bonds	4
PubChem molecular weight	152.15 g/mol	g/mol	PubChem

Safety

As a food flavouring, vanillin is essentially harmless: the FDA lists it as generally recognised as safe, and JECFA found no safety concern in its use as a flavouring agent. The pure powder is another matter, carrying the signal word Warning under the Globally Harmonised System (GHS) of hazard labels for serious eye irritation and a possible allergic skin reaction. The PubChem Laboratory Chemical Safety Summary is the reference for anyone handling the chemical.

Questions

Is vanillin the same as vanilla?

No. Vanillin is one compound, C₈H₈O₃, and vanilla bean extract is its major commercial natural source. Inside the bean it is held bound to a sugar as vanillin-4-beta-D-glucoside, the Hazardous Substances Data Bank (HSDB) records. The ratio of carbon-13 to carbon-12 has been used to reveal artificial vanillin mixed into natural vanilla extract.

What does the 3D model of vanillin show?

It shows 19 atoms and 19 bonds, with all eleven carbons and oxygens in one plane: a six-carbon ring carrying an aldehyde group (CHO), a methoxy group (OCH₃) and a hydroxyl group (OH) at positions 1, 3 and 4. The ring appears as alternating single and double bonds, although its pi electrons are shared around the ring. Every C–O bond and the O–H bond are polar, because oxygen attracts the shared electron pair more strongly than carbon or hydrogen.

Is vanillin safe to eat?

As a flavouring, yes. The US Food and Drug Administration (FDA) treats it as generally recognised as safe for its intended use, and JECFA, the food-additive expert committee of FAO and WHO, evaluated it in 2001 and again in 2019 and found no safety concern when it is used as a flavouring agent. California's Safe Cosmetics Program lists it as a fragrance allergen, hazardous only to people with fragrance allergies.

What happens to vanillin in the body?

In people it yields vanillic acid, according to HSDB. In rats vanillic acid was again the chief product, found both free and in conjugated (bound) forms, alongside conjugated vanillin, conjugated vanillyl alcohol and catechol. Microorganisms probably convert it to protocatechualdehyde. MeSH, the medical subject vocabulary, groups vanillin with antioxidants, substances that inhibit or retard oxidation reactions, and with anticonvulsants, drugs that prevent seizures or make them less severe. Both are index groupings, not approved uses of vanillin.

Made of the same elements

C₈H₈O₃ Methyl salicylate 19 atoms, 19 bonds.
C₉H₈O₄ Aspirin 21 atoms, 21 bonds.
C₇H₆O₃ Salicylic acid 16 atoms, 16 bonds.
C₆H₅COOH Benzoic acid 15 atoms, 15 bonds.
C₆H₈O₆ Ascorbic acid 20 atoms, 20 bonds.
C₆H₅CHO Benzaldehyde 14 atoms, 14 bonds.
C₃H₇COOH Butyric acid 14 atoms, 13 bonds.
CH₃COOC₂H₅ Ethyl acetate 14 atoms, 13 bonds.

All 51 compounds made of carbon, hydrogen and oxygen

C₃H₈O₃ Glycerol 14 atoms, 13 single bonds.
C₄H₈O Butanone 13 atoms, 12 bonds.
C₆H₈O₇ Citric acid 21 atoms, 20 bonds.
C₆H₅OH Phenol 13 atoms, 13 bonds.
C₃H₈O₂ Propylene glycol 13 atoms, 12 single bonds.
C₃H₇OH 1-Propanol 12 atoms, 11 single bonds.
C₃H₈O Isopropyl alcohol 12 atoms, 11 single bonds.
C₃H₆O₃ Lactic acid 12 atoms, 11 bonds.
C₄H₉OH 1-Butanol 15 atoms, 14 single bonds.
C₂H₅OC₂H₅ Diethyl ether 15 atoms, 14 single bonds.
C₄H₆O₅ Malic acid 15 atoms, 14 bonds.
C₂H₅COOH Propionic acid 11 atoms, 10 bonds.
C₃H₆O Acetone 10 atoms, 9 bonds.
C₂H₆O₂ Ethylene glycol 10 atoms, 9 single bonds.
C₆H₁₂O₆ Fructose 24 atoms, 24 single bonds.
C₆H₁₂O₆ Glucose 24 atoms, 24 single bonds.
C₄H₆O₆ Tartaric acid 16 atoms, 15 bonds.
CH₃OCH₃ Dimethyl ether 9 atoms, 8 single bonds.
C₂H₅OH Ethanol 9 atoms, 8 single bonds.
C₂H₄O₃ Glycolic acid 9 atoms, 8 bonds.
CH₃COOH Acetic acid 8 atoms, 7 bonds.
CH₃CHO Acetaldehyde 7 atoms, 6 bonds.
C₂H₄O Ethylene oxide 7 atoms, 7 single bonds.
C₁₄H₁₄O₃ Naproxen 31 atoms, 32 bonds.
H₂CO₃ Carbonic acid 6 atoms, 5 bonds.
CH₃OH Methanol 6 atoms, 5 single bonds.
H₂C₂O₄ Oxalic acid 8 atoms, 7 bonds.
HCOOH Formic acid 5 atoms, 4 bonds.
CH₂O Formaldehyde 4 atoms, 3 bonds.
C₁₅H₁₆O₂ Bisphenol A 33 atoms, 34 bonds.
C₁₃H₁₈O₂ Ibuprofen 33 atoms, 33 bonds.
C₁₀H₂₀O Menthol 31 atoms, 31 single bonds.
C₂₀H₁₄O₄ Phenolphthalein 38 atoms, 41 bonds.
C₁₂H₂₂O₁₁ Lactose 45 atoms, 46 single bonds.
C₁₂H₂₂O₁₁ Sucrose 45 atoms, 46 single bonds.
C₁₈H₂₄O₂ Estradiol 44 atoms, 47 bonds.
C₁₉H₂₈O₂ Testosterone 49 atoms, 52 bonds.
C₁₆H₃₂O₂ Palmitic acid 50 atoms, 49 bonds.
C₂₁H₃₀O₂ Progesterone 53 atoms, 56 bonds.
C₂₁H₃₀O₅ Cortisol 56 atoms, 59 bonds.
C₁₈H₃₄O₂ Oleic acid 54 atoms, 53 bonds.
C₂₇H₄₄O Cholecalciferol 72 atoms, 74 bonds.
C₂₇H₄₆O Cholesterol 74 atoms, 77 bonds.