API Intermediate · Guaifenesin KSM · Vanillin Feedstock
Guaiacol (2-methoxyphenol), the key starting material for the expectorant Guaifenesin and the main feedstock for synthetic vanillin. Supplied in pharma, flavour and technical grades by Chelora Pharmachem, Mumbai, and delivered across India with a batch COA and SDS.
How Buying Works
Send the quantity, grade (Ph. Eur./BP, pharma, flavour or technical), delivery city and target date. Quote CAS 90-05-1 so there is no confusion.
Price, lead time and packing in one reply, with the specification, COA and SDS/MSDS for your QA team to review.
Samples can be arranged for QC testing, process or flavour trials and vendor qualification before your commercial order.
Packed, labelled and sent with invoice, batch COA and transport documents. Repeat orders are planned with you.
Product Overview
Guaiacol (2-methoxyphenol, o-methoxyphenol, pyrocatechol monomethyl ether; CAS 90-05-1) is an aromatic ether-phenol: a benzene ring carrying a hydroxyl group (–OH) and a methoxy group (–OCH3) on neighbouring carbons. It melts at about 28 °C, so it is handled either as a colourless to pale yellow crystalline mass or as an oily liquid with a smoky, medicinal odour. Guaiacol is the key starting material for Guaifenesin, the expectorant found in many cough syrups and tablets.
Guaiacol is also the main feedstock for synthetic vanillin, made by condensing it with glyoxylic acid, and a flavouring substance in its own right (FEMA 2532), with the smoky, woody notes found in whisky, roasted coffee and wood smoke. In pharma it is used to make potassium guaiacolsulfonate and the epoxide intermediate for Ranolazine, and it has a long history as an expectorant and dental antiseptic. Researchers use it as an antioxidant model compound and as the classic substrate for peroxidase assays.
As a chemical supplier in Mumbai, Chelora Pharmachem supplies pharmacopoeia-grade, pharma-grade, flavour-grade and technical-grade guaiacol to API, flavour and fragrance, and specialty-chemical manufacturers across India, with a batch-wise COA, SDS/MSDS and specification. Tell us your grade, application and monthly volume, and our team quotes against your specification, from trial lots for process validation to regular bulk supply. We also supply Salicylic Acid, the starting material for Aspirin, and other aromatic intermediates for API synthesis.
In Depth
Guaiacol is the monomethyl ether of catechol. Its –OH and –OCH₃ groups sit on neighbouring (ortho) carbons, and an internal hydrogen bond between them helps explain its low melting point and good solubility in organic solvents. It is a weak phenolic acid with a pKa of about 10, so it dissolves in caustic soda as sodium guaiacolate, and it is moderately soluble in water.
The phenolic –OH is the reactive handle. Under basic conditions it is alkylated by glycidol or 3-chloro-1,2-propanediol to give Guaifenesin, and by epichlorohydrin to give guaiacol glycidyl ether, a Ranolazine intermediate. The ring is activated at the position para to the –OH, which is where glyoxylic acid attacks in the vanillin process. Guaiacol oxidises readily, which is why it darkens in air and light.
Most commercial guaiacol is made by O-methylating catechol, which is itself typically produced by hydroxylating phenol. Methylating agents include dimethyl sulphate, methanol or, in newer processes, dimethyl carbonate, and veratrole (the dimethyl ether) can form alongside. The crude product is purified by fractional distillation. Natural guaiacol is also recovered from wood creosote and lignin pyrolysis, mainly for flavour use.
Guaifenesin, 3-(2-methoxyphenoxy)propane-1,2-diol, is made by joining guaiacol to a three-carbon glycerol unit, usually glycidol or 3-chloro-1,2-propanediol in the presence of a base. Guaiacol is listed as Guaifenesin impurity A in the European Pharmacopoeia, so the assay, colour and related substances of the incoming material affect yield, purification load and final API quality. Guaifenesin is also the precursor of Methocarbamol.
Confirm the grade first (Ph. Eur./BP, pharma, flavour or technical), then compare assay, appearance and colour, freezing point, water content, non-volatile residue and related substances such as catechol (Ph. Eur. impurity A). Flavour houses also check odour and food-grade compliance. Because guaiacol darkens with age and exposure, ask for the manufacturing date and the COA and SDS of the actual batch.
Chelora Pharmachem supplies guaiacol (CAS 90-05-1) from its centralized sales office in Mumbai to API, flavour and fragrance, and specialty-chemical manufacturers across India. Share the grade, quantity, packing and delivery location, and our team replies with price, lead time and documents, from trial lots for process development to regular bulk supply for Guaifenesin and vanillin production.
Global Sourcing
Our focus is the Indian market. When local supply is short, or you need a specific origin, pharmacopoeia grade or flavour grade, our international sourcing desk brings guaiacol in from trusted producers abroad, and our Mumbai team handles import, documents and delivery to your plant.
Product Profile
The identifiers and properties purchase and QA teams ask for first. Batch values are always confirmed on the COA.
Identity
EC 201-964-7. Also sold as 2-methoxyphenol, o-methoxyphenol or pyrocatechol monomethyl ether.
A benzene ring with –OH and –OCH₃ on neighbouring carbons.
Appearance
Colourless to pale yellow crystals or oily liquid. Melts at about 28 °C and darkens in air and light.
Solubility
In water at 25 °C. Miscible with ethanol, ether, chloroform and oils; dissolves in caustic soda.
Technical Data
Reference data for Guaiacol, useful when writing a specification, checking an SDS or planning storage and transport.
| Property | Value |
|---|---|
| IUPAC name | 2-Methoxyphenol |
| Synonyms | Guaiacol, o-methoxyphenol, pyrocatechol monomethyl ether, 1-hydroxy-2-methoxybenzene, o-hydroxyanisole |
| CAS number | 90-05-1 |
| EC number | 201-964-7 |
| PubChem CID | 460 |
| Molecular formula | C7H8O2 |
| Molar mass | 124.14 g/mol |
| Appearance | Colourless to pale yellow crystalline mass, or an oily, highly refractive liquid with a characteristic smoky odour; darkens on exposure to air and light |
| Melting point | About 28 °C (literature 26–29 °C); it can stay liquid well below this temperature (supercooling) |
| Boiling point | 204–206 °C |
| Density | About 1.129 g/cm³ (solid, 25 °C); about 1.11 g/cm³ (liquid) |
| Refractive index | About 1.543 (nD20) |
| Flash point | About 82 °C (open cup); about 90 °C (closed cup) |
| Solubility in water | About 23 g/L at 25 °C (roughly 1 g in 60–70 mL) |
| Other solvents | Miscible with ethanol, diethyl ether, chloroform, oils and glacial acetic acid; soluble in sodium hydroxide solution |
| Acidity (pKa) | About 10 (phenolic –OH) |
| HS code | 2909.50 (ether-phenols); Indian tariff item 2909 50 10 |
| Transport | Generally not regulated as a dangerous good for road, sea or air; confirm with the batch SDS |
Literature values for reference. Supplied material is tested batch-wise and reported on the COA.
Applications
Its biggest jobs are Guaifenesin and vanillin. The same molecule is a smoky flavouring, a traditional expectorant and dental antiseptic, and a standard research reagent.
Guaiacol is the key starting material for Guaifenesin, the expectorant in cough syrups, tablets and combination cold products. By molar mass, about 0.63 kg of guaiacol goes into every kilogram of Guaifenesin, before process losses, which makes it a high-volume raw material for API makers.
Key starting material (KSM)
Most of the world’s synthetic vanillin is made from guaiacol. Condensation with glyoxylic acid gives vanillylmandelic acid, which is then oxidised and decarboxylated to vanillin, used in foods, beverages, confectionery, fragrances and pharmaceutical flavouring, and the same route gives related aroma chemicals.
Aroma chemical feedstock
Listed as a flavouring substance (FEMA 2532), guaiacol adds smoky, woody and spicy notes to smoke flavours, savoury seasonings, coffee and spirit flavours. It is also a starting point for other aroma chemicals, such as eugenol, made and used by flavour and fragrance houses.
Flavour ingredient
Guaiacol has long been used as an expectorant and antiseptic, and it is the parent of potassium guaiacolsulfonate, an expectorant in cough syrups. In dentistry it has been used for traditional pulp sedation, with eugenol in dry-socket preparations, and in root canal medicaments.
Pharma & dental use
A potent scavenger of reactive oxygen radicals, guaiacol is studied as an antioxidant model compound and in lignin and bio-based fuel chemistry. It is also the classic substrate for peroxidase assays, where enzymatic oxidation gives a coloured product read at 420–470 nm.
R&D and lab reagent
Quality & Compliance
Every supply is backed by the documents your QA, regulatory and stores teams expect.
COA, batch-wise
Tests, limits and results for the exact batch you receive, shared before dispatch.
SDS / MSDS
Hazards, safe handling, storage, transport and first-aid measures for Guaiacol.
Technical data
Typical properties and the specification we supply against, to match with your in-house spec.
On request
Additional documents for vendor approval and audits can be arranged on request.
Safety & Handling
A short summary for stores, production and EHS teams. It does not replace the Safety Data Sheet supplied with every batch.
Harmful if swallowed, causes skin irritation and causes serious eye irritation, as classified by major suppliers under GHS/CLP. Signal word: Warning. It is combustible, with a flash point of about 82–90 °C. Check the SDS of the batch for the classification that applies.
H302H315H319
Wear safety goggles, chemical-resistant gloves and protective clothing. Handle in a well-ventilated area or under local exhaust, avoid breathing vapour, and do not eat, drink or smoke while handling. Wash hands thoroughly after use.
Keep containers tightly closed in a cool, dry, well-ventilated store, protected from light and heat, and away from strong oxidising agents, strong bases, acid chlorides and acid anhydrides.
Guaiacol is generally not regulated as a dangerous good for road, sea or air transport (ADR, IMDG, IATA), so no UN number or packing group applies. Confirm with the transport section of the batch SDS.
Remove ignition sources, absorb spills with inert material such as sand or vermiculite, and collect into closed containers for disposal. It is not classified as hazardous to the aquatic environment, but keep it out of drains, soil and water courses.
PAN India Delivery
From our centralized sales office in Mumbai, we supply Guaiacol to buyers in every major manufacturing cluster.
MumbaiMumbai, Thane, Navi Mumbai, Tarapur, Boisar, Pune and Aurangabad.
AhmedabadAhmedabad, Vadodara, Ankleshwar and Vapi.
HyderabadHyderabad and Visakhapatnam.
BaddiBaddi and Haridwar.
GoaPharma and chemical units across Goa.
BengaluruBengaluru and Chennai.
IndoreIndore, Pithampur and Sikkim.
Specification
A typical specification for pharmacopoeia-grade guaiacol (Ph. Eur. / BP). Share your in-house, pharmacopoeia or flavour-grade specification and we quote against it.
The Chemistry
Made
Catechol is O-methylated on one hydroxyl group with a methylating agent such as dimethyl sulphate, methanol or dimethyl carbonate. The crude product is separated from unreacted catechol and over-methylated veratrole, then purified by fractional distillation to the grade required.
Used
Under basic conditions the phenolic oxygen of guaiacol opens the epoxide ring of glycidol, or displaces chlorine from 3-chloro-1,2-propanediol, giving 3-(2-methoxyphenoxy)propane-1,2-diol: Guaifenesin. Residual guaiacol is a controlled impurity in the finished API, so the purity going in matters.
Tested
Each batch is reported on a COA covering appearance, identification, assay, freezing point, water, non-volatile residue and related substances, against the grade and pharmacopoeia you ordered, so your QC and QA teams can review and release it quickly.
Stored
Guaiacol slowly darkens in air and light, and it may arrive solid or liquid depending on the temperature. Keep drums tightly closed and away from light, warm gently to melt before use if needed, and follow the SDS for handling and protective equipment.
Glossary
Terms you will meet on quotations, specifications and documents for Guaiacol.
FAQ
Anything else, call +91 98191 11179 or write to source@chelorapharmachem.com.
Request a QuoteGuaiacol (CAS 90-05-1) is the key starting material for the expectorant Guaifenesin and the main feedstock for synthetic vanillin. It is also used as a smoky flavouring, an intermediate for potassium guaiacolsulfonate, Ranolazine and aroma chemicals, in traditional expectorant and dental preparations, and as a research and peroxidase-assay reagent.
The CAS number is 90-05-1. Its formula is C7H8O2 and its molar mass is 124.14 g/mol. Quoting the CAS number on your enquiry avoids confusion with its isomers, 3-methoxyphenol and 4-methoxyphenol (mequinol, CAS 150-76-5).
Yes. Guaiacol, 2-methoxyphenol, o-methoxyphenol and pyrocatechol monomethyl ether are names for the same substance, CAS 90-05-1. Older texts may also call it methylcatechol, and pharmacopoeias list it under the name Guaiacol.
Guaifenesin is guaiacol joined to a glycerol unit: 3-(2-methoxyphenoxy)propane-1,2-diol. Guaiacol is the raw material; Guaifenesin is the finished expectorant API, with its own CAS number (93-14-1). Guaiacol is also limited as an impurity in Guaifenesin.
In theory about 0.63 kg, from the molar masses: 124.14 g/mol for guaiacol and 198.22 g/mol for Guaifenesin. Real consumption is a little higher, depending on your process yield.
We supply pharmacopoeia grade to Ph. Eur./BP, pharma grade of 99% or higher by GC, food and flavour grade, and technical grade for industrial use, subject to availability. Tell us the grade, application and any colour or impurity limits when you enquire.
Keep it in tightly closed containers in a cool, dry and well-ventilated store, protected from light and away from strong oxidisers, strong bases, acid chlorides and acid anhydrides. It melts at about 28 °C, so it may be solid or liquid on arrival; warm gently to melt it. Follow the SDS supplied with the batch.
Guaiacol is generally classified under HS subheading 2909.50, which covers ether-phenols, and under tariff item 2909 50 10 in India. Confirm the full national tariff code with your customs broker before import or export.
Yes. It is harmful if swallowed and causes skin and serious eye irritation, and it is a combustible material with a flash point of about 82–90 °C. Read the SDS before handling, and use eye protection, gloves and good ventilation.
Guaiacol is generally not regulated as a dangerous good for road, sea or air transport. Always check the transport section of the SDS supplied with the batch.
We provide a batch-wise Certificate of Analysis (COA), SDS/MSDS and specifications. Additional documents for vendor qualification can be arranged on request.
Yes. We handle requirements from samples and trial lots for R&D, process development, flavour trials and vendor approval up to regular bulk supply for commercial production, subject to product availability.
We supply buyers across India, including Maharashtra, Gujarat, Telangana, Andhra Pradesh, Himachal Pradesh, Goa, Karnataka, Tamil Nadu, Madhya Pradesh, Uttarakhand and Sikkim, from our centralized sales office in Mumbai.
Email source@chelorapharmachem.com or source@cheloragroup.com, call +91 98191 11179, or use the enquiry form on this page. Include the quantity, grade, delivery location and target date.
Request a Quote
Tell us the quantity, grade and delivery location. Our centralized sales team replies with competitive pricing, lead time and documentation.
