N,N-Diethylaniline
N,N-Diethylaniline (Diethylaminobenzene) · CAS 91-66-7
N,N-Diethylaniline is the ethyl counterpart of dimethylaniline and the building block for a brighter, bluer set of triarylmethane dyes, including brilliant green and the patent blue acid dyes. Nitrosation and reduction turn it into N,N-diethyl-p-phenylenediamine (DPD), the reagent used to test chlorine in water, and its hydrochloride's low hygroscopicity makes it a practical acid-binding base. Chelora Dyes supplies it lot-tested with batch data and a Safety Data Sheet on every shipment, so your synthesis starts from a consistent, characterised material.
Also sold as: N,N-Diethylbenzenamine · Diethylaniline · (Diethylamino)benzene · N,N-DEA
- CAS number
- 91-66-7
- Molecular formula
- C10H15N
- Molecular weight
- 149.24 g/mol
- Appearance
- Pale yellow liquid
Structure of N,N-Diethylaniline
Benzene ring with a diethylamino N(C2H5)2 groupWhat N,N-Diethylaniline is
A colourless to pale yellow liquid tertiary amine with two ethyl groups on the nitrogen. Like dimethylaniline it reacts at the para position, but the ethyl groups push its dyes to brighter, bluer shades and make it less volatile.
Identification
Use these details when you match N,N-Diethylaniline against your own purchase specification.
- Product name
- N,N-Diethylaniline
- Chemical name
- N,N-Diethylaniline (N,N-Diethylbenzenamine)
- CAS number
- 91-66-7
- EC / EINECS
- 202-088-8
- Molecular formula
- C10H15N
- Molecular weight
- 149.24 g/mol
- Product family
- Aromatic amine intermediates
- Common end use
- Triarylmethane dyes, DPD and colour developers, acid-binding base
Physical and chemical behaviour
The points that decide how the material handles on your plant and in your reactions.
- Appearance
- Colourless to pale yellow liquid with an amine odour. Yellows and then browns on exposure to air and light.
- Boiling and melting point
- Boils at 216–217 °C. Melts at about −38 °C, so it stays liquid in cold weather. Density about 0.938 g/mL at 25 °C.
- Solubility
- Very slightly soluble in water (about 0.13 g/L). Miscible with ethanol, diethyl ether, chloroform and aromatic solvents; dissolves in dilute mineral acids.
- Reactivity
- Electrophiles attack the para position: condensation with benzaldehydes gives triarylmethane leuco bases, nitrosation gives 4-nitroso-N,N-diethylaniline, and Vilsmeier formylation gives 4-diethylaminobenzaldehyde. As a hindered base it binds acids, and it forms a stable borane complex used as a reducing agent.
- Stability
- Stable in closed containers. Darkens slowly in air and light; keep it covered, ideally under nitrogen once opened.
- Incompatibilities
- Strong oxidising agents and peroxides, strong acids, acid chlorides and anhydrides, nitrosating agents. Combustible liquid (flash point about 83 °C); decomposition releases nitrogen oxides.
Typical specification
Every lot is tested in-house against its specification before dispatch, and the results travel with the shipment. If you work to a tighter window on any line below, send it to us and we will confirm whether we can supply to it.
| Parameter | Indicative value | Why it matters to you |
|---|---|---|
| Appearance | Clear, colourless to pale yellow liquid | A darker colour points to oxidation in storage or production, which carries into dye shade. |
| Purity | 99.0% minby GC | Sets the active content for condensation and nitrosation. Lower purity means weaker dye and lower yield. |
| N-Ethylaniline | 0.5% maxunder-ethylated amine | The secondary amine forms N-nitroso by-products in nitrosation and off-shade dyes in condensation. |
| Aniline | 0.1% maxfree primary amine | Diazotises and couples in its own right, adding impurities to dyes and to DPD. |
| Moisture | 0.1% maxby Karl Fischer | Water interferes with Vilsmeier formylation, acid-chloride steps and borane chemistry. |
| Colour | 100 maxHazen (APHA) | A quick check on freshness; oxidised material dulls bright greens and blues. |
| Density | 0.934–0.940 g/mLat 20 °C | Confirms identity, flags gross contamination and converts volume to weight on the plant. |
| Distillation range | 214–218 °C95% distilled | A narrow range confirms low levels of lighter and heavier impurities. |
Making dyes or DPD? Send us your purchase specification, including purity, N-ethylaniline and aniline limits, moisture and colour, through the contact page. We will confirm what we can supply, and send a sample with its test data so you can run it beside your current material.
Where N,N-Diethylaniline sits on the synthesis route
N,N-Diethylaniline is made by ethylating aniline. It is the last isolated step before condensation, nitrosation or formylation at the para position.
-
Benzene
The feedstock. Nitration with mixed acid (HNO3/H2SO4) gives nitrobenzene.
-
Aniline
Catalytic hydrogenation of nitrobenzene gives aniline, the parent primary amine.
-
N,N-Diethylaniline
Aniline is ethylated with ethanol over an acid catalyst under pressure, or with ethyl chloride. N-Ethylaniline forms first and is driven on to the tertiary amine, which is distilled — the intermediate you buy.
This product -
Para-substitution
The para position condenses with aldehydes, reacts with nitrosating agents and Vilsmeier reagent, and couples with diazonium salts.
-
Downstream products
Brilliant green and patent blue dyes, N,N-diethyl-p-phenylenediamine (DPD) after nitrosation and reduction, and 4-diethylaminobenzaldehyde.
Key derivatives of N,N-Diethylaniline
N,N-Diethylaniline is valued for what forms at its para position. Each derivative adds a carbon or nitrogen group opposite the diethylamino group.
Brilliant green
Two molecules of DEA condense with benzaldehyde; oxidising the leuco base gives the bright green triarylmethane dye used in selective culture media, as an antiseptic and for colouring.
- Class
- Cationic triarylmethane
- Partner
- Benzaldehyde
- Use
- Media, colouring
Patent blue dyes
Condensation with sulfonated benzaldehydes, then oxidation, gives the patent blue family of sulfonated triarylmethane acid dyes.
- Class
- Acid triarylmethane
- Partner
- Sulfonated benzaldehydes
- Use
- Wool, paper
N,N-Diethyl-p-phenylenediamine
Nitrosation para to the amine and reduction give DPD, the standard colour reagent for free and total chlorine in water and a photographic colour developer.
- CAS No.
- 93-05-0
- Route
- Nitrosation, reduction
- Use
- Water testing
4-Diethylaminobenzaldehyde
Formylation with DMF and phosphorus oxychloride gives the aldehyde, a building block for methine and styryl dyes and fine chemicals.
- CAS No.
- 120-21-8
- Route
- Vilsmeier–Haack
- Use
- Dyes, reagents
Need a related amine? N,N-Dimethylaniline is the methyl analogue behind crystal violet and malachite green, and N,N-Diethyl-M-Toluidine adds a meta methyl group for bluer azo couplings and the CD-2 colour developer. If you run several lines, they can come on the same order.
Where the chemistry leads
N,N-Diethylaniline is a specialist tertiary amine. It feeds bright triarylmethane dyes, analytical and photographic reagents, and synthesis steps that need a clean, non-hygroscopic base.
Triarylmethane dyes
DEA is the building block of brilliant green and the patent blue acid dyes. Dye makers need low N-ethylaniline and aniline, because both condense or couple into off-shade by-products that dull these very bright colours.
Water-testing and photographic reagents
Nitrosation and reduction give N,N-diethyl-p-phenylenediamine (DPD), the colour reagent in most free and total chlorine test kits and a colour developer for photographic processing.
Synthesis and pharmaceuticals
As a hindered tertiary amine, DEA binds acids in acylations without forming a hygroscopic salt, and its borane complex is used as a selective reducing agent.
What buyers check before they switch supplier
Four parameters explain most of the yield, shade and purity complaints when a manufacturer changes its source of N,N-Diethylaniline.
Purity and N-ethylaniline
The secondary amine forms N-nitroso compounds during nitrosation and off-shade products in dye condensations.
Free aniline
Aniline couples and condenses on its own, adding coloured impurities to dyes and unwanted amines to DPD.
Moisture
Water interferes with Vilsmeier formylation, acid-chloride steps and borane reagents.
Colour and storage history
Oxidised, darkened material dulls brilliant greens and patent blues. Hazen colour is the quick check.
Tested in-house, documented in full
Consistent downstream chemistry starts with a consistent intermediate. Each lot of N,N-Diethylaniline is checked against its specification before it leaves, and the result goes out with the material so your goods-in team can release it without a second test.
- Each lot tested against the product specification before dispatch
- Batch test report supplied with every shipment
- Safety Data Sheet supplied with the first order and on request
- Technical and specification sheets available before you order
- Samples sent with their own test data, so a trial compares like with like
- Chemists familiar with tertiary amine condensation and nitrosation chemistry, available to discuss results
What arrives with the material
Enough paperwork for your goods-in and quality teams to release the lot without retesting it.
- Batch test report
- The tested figures for the lot you have received, set against the specification.
- Safety Data Sheet
- Classification, protective equipment, storage conditions, first aid and spill response.
- Specification sheet
- The parameters and limits we supply against, available before you place the order.
- Sample test data
- Sent with every trial sample, so a comparison against your current material starts from the same numbers.
Packing, storage and handling
N,N-Diethylaniline is a stable liquid in closed containers, but it is toxic, combustible and absorbed through the skin. Follow all guidance in the Safety Data Sheet for protective equipment and exposure control.
How it ships
- Supplied in sealed HDPE or lined steel drums, filled to leave headspace for expansion
- IBCs and bulk loads can be discussed where your process suits larger volumes
- Every container carries the product name, lot number and hazard labelling
- Pack size can be matched to your batch charge to minimise part-opened containers
- Shipped with its batch test report and Safety Data Sheet
Storing and handling on site
- Store in a cool, dry, well-ventilated area, away from direct sunlight and sources of ignition
- Keep containers tightly closed; once opened, blanket with nitrogen to slow darkening by air oxidation
- Store on bunded floors or in drip trays and transfer through closed lines or with local exhaust ventilation
- Wear the protective equipment specified in the SDS — the liquid is absorbed through intact skin
- Keep apart from peroxides, oxidising agents, strong acids and nitrosating agents
- Rotate stock so older lots are used first
Read the Safety Data Sheet before first use. N,N-Diethylaniline is classified as toxic if swallowed, in contact with skin or if inhaled, causes skin irritation, may cause damage to organs through prolonged or repeated exposure, and is toxic to aquatic life with long-lasting effects. It is absorbed through the skin and can cause methaemoglobinaemia. It is a combustible liquid. The SDS sets out the required PPE, exposure controls, storage conditions, first-aid measures and spill response. If anything on it is unclear, ask our technical team.
How to order N,N-Diethylaniline
Start with a sample, move to scheduled supply. Four steps from first enquiry to a delivery pattern that matches your production plan.
Send your requirement
Product name, grade or specification, quantity, packing and delivery location, through the contact page.
Get the paperwork
We come back with the specification sheet, the Safety Data Sheet and a quote against your quantity and packing.
Run a sample
A sample with its test data, so you can run it through your condensation, nitrosation or other process beside your current material.
Confirm supply
Once the trial clears, we schedule repeat supply to the same specification, lot after lot.
N,N-Diethylaniline: frequently asked questions
What buyers, chemists and plant teams ask us most about this product. For anything else, get in touch.
What is N,N-Diethylaniline?
N,N-Diethylaniline (CAS 91-66-7) is a colourless to pale yellow liquid tertiary aromatic amine: aniline with two ethyl groups on the nitrogen. It is a building block for triarylmethane dyes, DPD reagent and colour developers, and a hindered acid-binding base.
What is the CAS number and molecular formula?
The CAS number is 91-66-7. The EC (EINECS) number is 202-088-8. The molecular formula is C10H15N and the molecular weight is 149.24 g/mol.
How is N,N-Diethylaniline manufactured?
Aniline is ethylated, either with ethanol over an acid catalyst at elevated temperature and pressure, or with ethyl chloride. The reaction passes through N-ethylaniline to the tertiary amine, which is purified by distillation.
Which dyes are made from N,N-Diethylaniline?
Brilliant green (with benzaldehyde) and the patent blue family of sulfonated acid dyes (with sulfonated benzaldehydes) are the best-known. It is also used as a coupling component for azo dyes.
Why do diethylaniline dyes look brighter and bluer than dimethylaniline dyes?
Ethyl groups donate slightly more electron density to the nitrogen than methyl groups, which shifts the absorption of the finished dye to longer wavelengths. Brilliant green, for example, is bluer than its dimethyl counterpart malachite green.
What is DPD, and how is it made from DEA?
DPD is N,N-diethyl-p-phenylenediamine (CAS 93-05-0). N,N-Diethylaniline is nitrosated at the para position, and the nitroso compound is reduced to the diamine. DPD is the standard colour reagent for chlorine testing in water.
Why is DEA used as an acid-binding base?
It is a weak, hindered tertiary base that mops up acid released in acylations without competing as a nucleophile. Its hydrochloride is not hygroscopic, which makes the salt easy to handle and filter.
Is N,N-Diethylaniline soluble in water?
Only very slightly, at about 0.13 g per litre. It mixes freely with ethanol, diethyl ether, chloroform and aromatic solvents, and dissolves in dilute mineral acids.
What is the diethylaniline-borane complex?
N,N-Diethylaniline forms a stable, liquid complex with borane. It is used in organic synthesis as a convenient, selective reducing agent that is easier to handle than borane gas or its solutions.
How does it differ from N,N-Dimethylaniline?
N,N-Dimethylaniline has methyl groups on the nitrogen, boils at about 194 °C and freezes at about 2 °C. N,N-Diethylaniline boils at about 217 °C, stays liquid down to about −38 °C and gives brighter, bluer dyes.
What purity do you supply?
Standard commercial material is supplied at a minimum purity of 99% by GC, with the actual figure for your lot on the batch test report. If you work to tighter limits on N-ethylaniline, aniline or colour, send your specification and we will confirm what we can supply.
What is the boiling point, and why does it matter?
N,N-Diethylaniline boils at 216–217 °C. A narrow distillation range on the specification confirms low levels of lighter N-ethylaniline and aniline and of heavier residues.
Is N,N-Diethylaniline hazardous?
Yes. It is toxic by ingestion, skin contact and inhalation, can damage organs through repeated exposure, can cause methaemoglobinaemia and is toxic to aquatic life. It is also a combustible liquid. Handle it with the controls and protective equipment set out in the Safety Data Sheet.
How is it packed and stored?
It ships in sealed HDPE or lined steel drums, labelled with the product name, lot number and hazard information. Store it cool, ventilated, away from light and ignition sources, and apart from oxidisers, strong acids and nitrosating agents.
Can I get a sample, and is there a minimum order?
Yes to samples, sent with their test data so a trial compares like with like. Order quantities depend on the packing, so tell us the volume you expect through the contact page and we will confirm what is practical.
Tell us the grade and quantity of N,N-Diethylaniline you need
Send your specification, the quantity and where it ships to, and our technical team will come back with the specification sheet, a quote and a sample plan. If you also buy N,N-Dimethylaniline or N,N-Diethyl-M-Toluidine, put them on the same enquiry.