Introduction
2,2-Difluoroethanol (CAS 359-13-7), also written CHF2CH2OH or 2,2-difluoroethan-1-ol, is a small fluorinated alcohol: a colorless transparent liquid in which a difluoromethyl group sits next to a primary hydroxyl. That combination is what makes it commercially interesting. The difluoromethyl (CHF2) group is a valued motif in modern active ingredients, while the primary alcohol gives chemists a convenient handle for further elaboration. As a result, 2,2-difluoroethanol is used mainly as a fluorinated building block for pharmaceutical, agrochemical and specialty chemical synthesis.
Chemical and Physical Properties
2,2-Difluoroethanol is the difluorinated analogue of ethanol. The two fluorine atoms on the terminal carbon make the molecule noticeably more polar and more acidic than ethanol, and they strongly influence its reactivity and its behaviour as a solvent or intermediate.
| Property | Value |
|---|---|
| CAS number | 359-13-7 |
| Molecular formula | C2H4F2O |
| Molecular weight | 82.05 g/mol |
| Appearance | Colorless transparent liquid |
| EC number | 670-547-3 |
| Chemical family | Fluorinated alcohol (difluoromethyl, primary alcohol) |
| SMILES | C(C(F)F)O |
Because it carries both a strongly electron-withdrawing CHF2 group and a hydrogen-bonding hydroxyl, 2,2-difluoroethanol is a polar liquid that mixes readily with water and with polar organic solvents. That solvent behaviour, together with its reactivity, is why it appears both as a reagent and as a reaction medium in fine-chemical work.
Why the Difluoromethyl Group Matters
In medicinal and crop-protection chemistry, hydrogen-to-fluorine substitution is one of the most reliable ways to tune a molecule’s properties. The difluoromethyl group is a particularly useful example:
- Metabolic stability. Fluorine-carbon bonds resist oxidative metabolism, which can extend the lifetime of an active ingredient in the body or the field.
- Lipophilicity and pKa tuning. The CHF2 group changes lipophilicity and can act as a weak hydrogen-bond donor, shifting how a molecule interacts with its target.
- Bioisosteric replacement. CHF2 can stand in for groups such as methyl, hydroxymethyl or thiol in a scaffold while preserving geometry.
2,2-Difluoroethanol is one of the simplest and most practical ways to deliver that group into a synthesis, which is why it is a staple fluorinated building block.
Production and Synthetic Routes
2,2-Difluoroethanol is made by introducing the difluoromethyl group on a two-carbon backbone. The main industrial approaches are:
- Fluorination of a C2 precursor. Chlorinated or oxygenated C2 intermediates can be converted to the difluoro compound with a fluorinating agent such as HF or a metal fluoride, followed by work-up.
- Reduction of a difluoro ester or acid derivative. Reducing an appropriate difluorinated carbonyl compound (for example an ester) gives the alcohol directly.
- Addition routes from fluorinated C1/C2 building blocks. Fluorinated starting materials can be assembled to the two-carbon alcohol.
Whichever route is used, the crude product is purified by distillation, because assay, acidity and water content are the parameters that decide whether the material is suitable for sensitive downstream chemistry.
Reactivity and Derivative Chemistry
The primary hydroxyl group makes 2,2-difluoroethanol a versatile starting point:
- Esterification to difluoroethyl esters, useful as solvents, intermediates and protecting-group partners.
- Ether formation to introduce a difluoroethyl group into a molecule.
- Oxidation to the corresponding difluorinated carbonyl derivative.
- Conversion to halides or other leaving groups, giving difluoroethyl electrophiles for alkylation chemistry.
Because the CHF2 group is robust under many conditions, these transformations usually leave the fluorine substitution intact – the main reason the compound is valued as a delivery vehicle for the difluoromethyl motif.
Applications
Pharmaceutical synthesis
2,2-Difluoroethanol is used to build difluoroethyl and difluoromethyl functionality into drug candidates and intermediates, where the fluorine substitution improves metabolic stability and tunes the molecule’s physical properties.
Agrochemical synthesis
In crop protection, difluoromethyl-containing actives are well established; 2,2-difluoroethanol is a convenient two-carbon source of that group for herbicide, fungicide and insecticide chemistry.
Specialty and functional chemicals
The compound is also used to make fluorinated esters, ethers and other specialty fluorochemicals, and as a polar fluorinated alcohol in synthesis and process development.
Quality and Specifications
2,2-Difluoroethanol is sold against a short specification in which assay, acidity and water are the parameters that matter most.
| Parameter | Specification |
|---|---|
| Appearance | Colorless transparent liquid |
| Assay | 99.5% min |
| Acidity | 0.0001% max |
| Water | 0.1% max |
| Molecular formula | C2H4F2O |
| Molecular weight | 82.05 g/mol |
The very low acidity limit signals a well-neutralised product with essentially no residual acid, and the tight water limit matters because the material is used in moisture-sensitive chemistry. More detail on the commercial side is in the 2,2-difluoroethanol buying guide.
Handling, Safety and Storage
2,2-Difluoroethanol is a flammable fluorinated alcohol and should be handled as a reactive organic liquid:
- Keep away from heat, sparks and open flames; store cool, dry and tightly closed.
- Use appropriate personal protective equipment (gloves, eye protection, suitable clothing) and work in a well-ventilated area.
- Avoid contact with strong oxidising agents and follow the safety data sheet for first aid and spill procedures.
- Keep the container closed when not in use to limit moisture pick-up and vapour release.
Frequently Asked Questions about 2,2-Difluoroethanol
What is 2,2-difluoroethanol used for?
It is used mainly as a fluorinated building block – a convenient source of the difluoromethyl group – in pharmaceutical, agrochemical and specialty chemical synthesis.
Is 2,2-difluoroethanol the same as fluoroethanol?
No. 2,2-Difluoroethanol (CHF2CH2OH) carries two fluorine atoms on the terminal carbon; it is a distinct fluorinated alcohol with its own specification and handling requirements.
Why is a low acidity limit specified?
A limit of 0.0001% max indicates a well-neutralised product free of residual acid, which matters for sensitive downstream reactions.
Where can I buy 2,2-difluoroethanol?
PolyBlueChem supplies 2,2-difluoroethanol (CAS 359-13-7) with COA and MSDS. Contact our team for specifications, packaging and a quotation.
References
- PubChem Compound Summary for 2,2-difluoroethanol (CAS 359-13-7).
- Manufacturer specification sheets for 99.5% min 2,2-difluoroethanol.
- General reference material on fluorinated alcohols and difluoromethyl building blocks in active-ingredient synthesis.
Disclaimer: This article is provided for general informational purposes only and does not constitute technical, medical, regulatory or safety advice. Always refer to the current safety data sheet and applicable regulations before handling this material.
PolyBlueChem, as the chemical supplier of all categories, is the supplier of 2,2-difluoroethanol (CAS 359-13-7) as well. Contact our team for specifications, packaging and a quotation.