Diethyl Sulfate
Diethyl sulfate does for ethyl groups what dimethyl sulfate does for methyl groups — a clean, high-yield industrial ethylating agent used wherever the target molecule needs an N-ethyl, O-ethyl or S-ethyl group rather than a methyl one.
Chelora Chemicals supplies diethyl sulfate to dye, pharmaceutical and agrochemical producers worldwide, in UN-approved packing, with a batch COA and GHS safety data sheet on every consignment.
Product identity
- CAS Number
- 64-67-5
- IUPAC name
- Diethyl sulfate
- Molecular formula
- C₄H₁₀O₄S
- Molecular weight
- 154.19 g/mol
- EC / EINECS
- 200-589-6
- UN Number
- 2217 · Class 6.1
- SMILES
- CCOS(=O)(=O)OCC
- HS Code
- 2920 90*
* Confirm the exact HS heading with your customs broker — esters of inorganic acids can sit under a different subheading depending on the destination tariff schedule.
What Diethyl Sulfate is used for
Diethyl sulfate is a colorless, oily liquid with a faint peppermint-like odor, structurally identical in logic to dimethyl sulfate but carrying two ethyl groups instead of two methyls. It is the reagent of choice whenever the synthesis target specifically needs an ethyl group transferred rather than a methyl one.
Its principal use is N-ethylation of aromatic amines — producing N,N-diethylaniline derivatives that feed into dye-intermediate and optical-brightener chemistry — alongside O-ethylation steps across pharmaceutical and agrochemical synthesis where an ethyl ether or ethyl ester group is the target.
Where it sits among alkylating agents
- Diethyl sulfate (this product) the standard bulk ethylating agent; two ethyls transferred per molecule.
- Dimethyl sulfate the methylating equivalent, used where the target needs a methyl rather than an ethyl group. See that page.
- Ethyl bromide / ethyl iodide more reactive but considerably more expensive alternatives, generally reserved for smaller-scale synthesis.
- N,N-Diethyl-m-Toluidine a typical downstream target made using this reagent's ethylating chemistry. See that page.
On a potent alkylating agent, confirm the CAS number and handling protocol on your purchase order — see the full alkylating-agent range.
Appearance and handling character
The material ships as a colorless to pale yellow, oily liquid, slightly soluble in water and hydrolysing slowly to ethanol and sulfuric acid, faster with heat. Like dimethyl sulfate it is classified as a suspected human carcinogen and is toxic by all exposure routes including skin absorption. The safety section below should be read before any handling is planned.
| Parameter | Typical value |
|---|---|
| Appearance | Colorless to pale yellow oily liquid |
| Assay | 98.0% min |
| Acidity (as H2SO4) | 0.1% max |
| Color / APHA | Reported per batch |
| Moisture | Reported per batch |
Important: the figures above are indicative of commercial-grade material and are offered for planning only. The batch certificate of analysis is the governing document. Assay and acidity are the figures that most affect ethylation yield — tell us your target and we will quote against it.
| Property | Value |
|---|---|
| Physical state | Oily liquid at ambient |
| Melting point | − 24.5 °C |
| Boiling point | 209–210 °C @ 760 mmHg |
| Density | 1.17 g/cm³ @ 20 °C |
| Water solubility | Slightly soluble; hydrolyses slowly |
| Vapor density | Heavier than air |
Physical constants compiled from public reference data for CAS 64-67-5 and rounded for readability. Treat them as orientation, not as a specification.
Where our customers put this reagent to work
This reagent is bought for the ethyl group it transfers. The applications below are all variations on that one reaction.
N-ethylation of aromatic amines
Converts aniline-type amines to their N,N-diethyl derivatives, a standard step in dye-intermediate and optical-brightener synthesis.
- Dye and pigment intermediate routes
- See our related intermediate page
- Colour-critical specification on request
Pharmaceutical & agrochemical synthesis
O- and N-ethylation steps appear throughout active pharmaceutical ingredient and crop-protection chemical synthesis.
- API and agrochemical intermediate routes
- End-use declaration required
- Technical desk review of your route
Ethyl ether & ester synthesis
Converting a phenol, alcohol or acid to its ethyl derivative is a routine step across fine-chemical manufacture.
- Fine chemical intermediate routes
- Full impurity profile on request
- Laboratory grade available
Specialty surfactant & catalyst intermediates
Selected quaternary ammonium and phase-transfer catalyst syntheses use this reagent where an ethyl rather than methyl group is specified.
- Custom synthesis quantities available
- Technical support for your route
- Small DG-compliant packs
Research & laboratory ethylation
Small-scale ethylation in process development and analytical derivatization, handled under the same strict controls as plant scale.
- Reference-grade material on request
- Full analytical documentation available
- Small DG-compliant packs
Contract & scheduled supply
Dye and pharma plants consume this reagent on a fixed schedule. We hold inventory and release it against your production calendar.
- Annual contracts with scheduled call-off
- Price held across the contract period
- Second source held in reserve
How we supply Diethyl Sulfate
Chelora Chemicals is a supplier and sourcing partner, not a manufacturer. On a reagent classified as a suspected human carcinogen, owning no plant means we are never selling you whatever a captive unit happens to be running — we route your order to the producer whose packaging and documentation actually matches a controlled handling protocol.
We place your order with whichever qualified producer best matches your assay, your specification, your price point and your delivery window.
We keep a second qualified source on this line. When a plant goes down for maintenance, your order switches source rather than stalling.
- Assay and acidity confirmed before we quote. 98% min with low free acidity is the commercial standard — we state both figures on the COA.
- Carcinogen classification stated up front. We say so at enquiry stage, every time, so your EHS team can plan engineering controls before the first drum arrives.
- Batch COA shared before dispatch. You approve assay and acidity against your own spec while the material is still in our warehouse.
- Skin absorption flagged explicitly. Diethyl sulfate is absorbed through intact skin — we state this so your controls target the actual exposure route.
- Pre-shipment samples for qualification. New account or new source, your laboratory runs a trial before the full quantity ever moves.
- Export machinery handled in-house. UN 2217 classification, approved packing, labelling, freight booking and customs paperwork are ours to manage.
Packed the way your plant receives it
Pack format drives your landed cost and your handling effort. Tell us how the material will be charged at your end and we will quote the format that suits your operation.
Lined steel / HDPE drums
UN-approved, lined drums for Class 6.1 liquids — the standard commercial format and the easiest for closed-system charging.
ISO / flexitank containers
Bulk ISO tank or flexitank movement for continuous-consumption plants, reducing drum handling and its exposure risk.
Road tanker (regional)
Dedicated tankers for domestic and cross-border delivery where receiving infrastructure exists at both ends.
Trial / sample quantities
Small, DG-compliant containers dispatched so your R&D team can qualify the grade before committing to larger volumes.
Incoterms to suit you
Quoted on the Incoterm your purchasing team works to, with DG documentation filed before the booking is made.
Campaign despatch
We hold contracted tonnage and release it against your production calendar instead of landing it all at once.
Skin absorption is the controlling route
Diethyl sulfate is toxic by the oral, dermal and inhalation routes, absorbed through intact skin, and classified as a suspected human carcinogen with mutagenicity concerns. The summary below is orientation only — the safety data sheet supplied with your consignment is the authoritative document.
Classified hazards
H301 + H331Toxic if swallowed or if inhaled.H314Causes severe skin burns and eye damage.H315Causes skin irritation.H350May cause cancer.H341Suspected of causing genetic defects.H373May cause damage to organs through prolonged or repeated exposure.
Hazard statements reflect classifications commonly published for CAS 64-67-5. As with other alkylating agents of this class, a delayed-presentation risk applies — a casualty who feels well immediately after exposure may still develop symptoms some hours later. Always read the SDS issued with your specific batch.
Spill & emergency orientation
Plan your response before the pallet arrives. Sections 4, 5 and 6 of the SDS are the authoritative instructions and should be posted at the point of use.
- Contain, do not hose to drain. Collect spilled liquid with inert absorbent and dispose of it as regulated chemical waste.
- Assume skin absorption. Contaminated clothing is a continuing exposure route — remove it immediately and wash the skin thoroughly with soap and water.
- Expect delayed presentation. Symptoms from significant exposure can appear hours later — any exposed person should be medically assessed promptly, with the SDS in hand, even if they feel well.
- Ventilate and avoid vapor inhalation. Vapor is heavier than air and will accumulate in low-lying or enclosed spaces — ventilate before re-entry.
- Decontaminate equipment thoroughly. Residual DES on tools or surfaces remains hazardous until fully neutralised and rinsed.
Storage
- Cool, dry, well-ventilated, access-controlled store. Away from direct sunlight and heat sources; elevated temperature accelerates hydrolysis and vapor generation.
- Keep containers tightly closed. On a sealed and bunded floor — vapor escape is a genuine and serious exposure route on this product.
- Segregate from amines, ammonia and strong bases. These react readily with diethyl sulfate, some combinations violently.
- Restrict access and log entry. With a carcinogen classification, controlling who enters the store is a core control measure, not an optional one.
- Shelf life typically 12–24 months. In sealed original packing, away from heat. Re-assay before use after extended storage.
Handling & PPE
- Design skin and vapor contact out. Closed transfer, contained charging and local exhaust ventilation first; PPE last, never as the sole control.
- Chemical-resistant gloves, coveralls and face shield. With contaminated clothing removed, bagged and handled as contaminated waste rather than sent to an ordinary laundry.
- Respiratory protection for vapor. Organic-vapor cartridge respirators or supplied air during any operation that can generate vapor, per your exposure assessment.
- Health surveillance for exposed workers. Given the carcinogen classification, your occupational health provider should define a monitoring programme for routine handlers.
- Never discharge to drain or watercourse. Contain and dispose of as regulated chemical waste.
Transport
Diethyl sulfate moves as regulated cargo under UN 2217, Class 6.1. We classify each consignment, apply UN-approved packaging and labelling, and file the dangerous-goods declaration before the booking is made — ask us for the current DG paperwork when you plan the shipment.
What travels with every consignment
A chemical shipment is only as good as the file that travels with it. Verifying what the source plant sends is precisely the work you are buying from a supplier.
Certificate of Analysis
Batch-specific assay, acidity and moisture — checked against your purchase specification before release.
GHS Safety Data Sheet
Full 16-section SDS in GHS format covering hazards, exposure controls, handling, storage, spill response, toxicology and disposal, issued in the language your destination requires.
Dangerous Goods Declaration
UN 2217, hazard class and IMDG or RID/ADR declaration prepared and filed before the container is booked, with correctly marked and labelled packaging.
Certificate of Origin
Chamber-attested where required, plus preferential-origin forms where a trade agreement gives your import duty relief.
Third-party inspection
SGS, Intertek or Bureau Veritas sampling and inspection arranged on request before loading, giving you independent verification of what actually ships.
Retained & pre-shipment samples
Pre-shipment samples carry the same COA as the commercial lot, so what your laboratory qualifies is exactly what arrives.
Two ethyl groups, one sulfate ester
Both ethyl groups in diethyl sulfate are electrophilic and available for transfer to a nucleophile — the same logic as dimethyl sulfate, one carbon longer. The routes below are the general industrial pattern, not a process disclosure.
React ethanol with SO3 or oleum
Ethanol reacts with sulfur trioxide or fuming sulfuric acid to form the sulfate ester.
Distill and purify
Crude diethyl sulfate is distilled to remove unreacted ethanol, ethyl hydrogen sulfate and sulfuric acid.
Transfer an ethyl group to the nucleophile
In use, an amine, phenol or other nucleophile displaces ethyl sulfate, taking up one ethyl group and releasing ethyl hydrogen sulfate.
Neutralise the spent acid co-product
The ethyl hydrogen sulfate co-product is neutralised and worked up as part of standard process design.
Why assay and acidity carry through the whole route
On an ethylating agent, small changes in purity change the ethylation yield directly:
- Free acidity signals partial hydrolysis. Hydrolysed DES has already given up ethylating power to water, lowering effective strength per kilogram charged.
- Moisture accelerates further hydrolysis in storage. Which is why moisture is tracked on the COA even though it is a minor figure in absolute terms.
- Color darkening usually tracks acidity. A quick, practical read on batch quality before the full assay comes back.
- Stoichiometry is unforgiving on a two-ethyl reagent. Under-dosing leaves unreacted substrate; over-dosing wastes reagent and complicates work-up.
That is why we quote against your written assay and acidity limits rather than a generic "technical grade", and why the batch COA is shared for approval before dispatch rather than sent with the invoice.
| Material | Downstream / use |
|---|---|
| Diethyl sulfate CAS 64-67-5 — this product | Bulk O-, N- and S-ethylation |
| Dimethyl sulfate CAS 77-78-1 | Bulk O-, N- and S-methylation |
| N,N-Diethyl-m-Toluidine CAS 91-67-8 | Typical downstream N-ethylated intermediate |
| Ethyl bromide CAS 74-96-4 | Higher-reactivity, smaller-scale ethylation |
We supply across this intermediate family — see the full intermediate range. Send the CAS number and we will confirm the correct material before quoting.
What actually moves the price of this product
Knowing what drives the quote helps you time a purchase and read whether an offer is realistic.
Ethanol and sulfur feedstock
DES is made from ethanol and SO3/oleum, so both feedstock markets feed through to price on their own cycles.
- Ethanol tracks agricultural and petrochemical cycles
- Sulfur/oleum cost follows the acid-plant cycle
- We flag feedstock-driven moves in the quote
Handling and regulatory compliance cost
Carcinogen classification brings storage, training and health-surveillance obligations that sit inside the delivered price wherever they apply.
- Handling obligations vary by jurisdiction
- We check destination rules before quoting
- Ask about documentation for your site
Freight and DG surcharges
Class 6.1 cargo carries a hazardous surcharge, and carriers increasingly restrict routing for carcinogen-classified liquids.
- Compare on landed cost, not ex-works
- DG space books out ahead of peak season
- We quote FOB, CIF, CFR or DDP as you prefer
Co-product and plant economics
Alkylating-agent plants balance DES output against dimethyl sulfate and sister products on the same line.
- Ask us what the sister market is doing
- Contracted call-off smooths the exposure
- We hold a second qualified source
Source availability
A plant turnaround, environmental inspection or feedstock disruption can take capacity offline at short notice.
- We hold a second qualified source on this line
- Qualify the alternate before you need it
- Ask us about dual-source contracts
Smaller market than dimethyl sulfate
Lower overall demand than the methylating equivalent means fewer qualified producers and less buffer stock in the supply chain.
- Plan lead time accordingly on large orders
- We hold inventory to smooth this
- Ask us about scheduled call-off
| If your end use is… | Specify |
|---|---|
| Dye / pigment N-ethylation | 98% min assay, low acidity, colour-critical |
| Pharma / agrochemical intermediate | Full impurity profile, end-use declaration |
| Quaternary ammonium / catalyst synthesis | Standard commercial grade |
| Laboratory / analytical derivatization | Small DG-compliant pack, full COA |
Not sure which column you are in? Describe what you make from it and our technical desk will recommend the grade — including telling you when a cheaper specification would do the job just as well.
Support that goes beyond shipping the drum
What our technical desk will do
- Confirm assay and acidity before anything else. On this reagent both figures decide ethylation yield, and we settle them in the first reply.
- Be straight about the carcinogen classification. Suspected human carcinogen, skin-absorbed, toxic by all routes — stated at enquiry stage so your EHS team can plan engineering controls before the first delivery.
- Review your handling and ventilation setup. We ask about your transfer and charging method before the first drum moves, not after an exposure incident.
- Review your specification before it goes into a contract. So you are not locked into a purity no plant can consistently hit.
Regulatory & compliance notes
- Carcinogen handling obligations are jurisdiction-specific. Several regimes impose exposure monitoring, health surveillance and record retention for this class. Confirm what applies at your site before the first delivery.
- Import controls vary by destination. We check destination rules before quoting, not after you have raised the PO.
- Chemical inventory listings differ between regions. We will supply the identity data you need for that filing.
- Effluent and waste rules matter. Check your discharge consent against the material before introducing it to site.
None of the above is legal advice — your own regulatory affairs team owns the final compliance position for your import and your workplace. What we commit to is accurate product identity data, an honest statement of the hazard classification and complete documentation to work from.
From enquiry to delivered pallet
Send the specification
Product name or CAS 64-67-5, your assay and acidity requirement, quantity, pack preference and destination port.
Receive a firm quote
Pricing, lead time, packing and Incoterm confirmed in writing within 24 hours — our sourcing desk is staffed around the clock.
Qualify and approve
Sample dispatched if you are qualifying a new source. Batch COA shared for your approval before the material is released.
Ship and track
UN 2217 classification filed, DG freight booked, export documents issued, and the consignment tracked through transit and clearance to your plant.
What buyers ask us about Diethyl Sulfate
What is diethyl sulfate used for?
Is diethyl sulfate a carcinogen?
How is it different from dimethyl sulfate?
Is it absorbed through the skin?
What purity do you normally supply?
What is the minimum order quantity?
How should we store it?
Is this a dangerous good? What paperwork comes with it?
Do you manufacture this yourself?
Request pricing on Diethyl Sulfate
Send your required assay, acidity limit, quantity, pack format and destination port. Our sourcing desk is available 24 hours a day, 7 days a week, and comes back with pricing, lead time and packing options — whether that is a single trial pack or a contracted programme for the year.