| HS Code | 769380 |
| Productname | Potassium Ethoxide |
| Chemicalformula | C2H5KO |
| Molecularweight | 84.16 g/mol |
| Casnumber | 917-58-8 |
| Ecnumber | 213-029-0 |
| Synonyms | Potassium ethanolate; Potassium ethylate; Ethanol, potassium salt |
| Appearance | White to off-white or yellowish crystalline powder or solid |
| Physicalstate | Solid at room temperature; commonly supplied as an ethanolic solution |
| Odor | Alcohol-like odor when in ethanol solution |
| Meltingpoint | Decomposes on heating; no sharp melting point |
| Density | Approximately 0.89 g/cm3 |
| Solubilityinwater | Reacts with water; hydrolyzes to ethanol and potassium hydroxide |
| Solubilityinorganicsolvents | Soluble in ethanol; slightly soluble in other polar organic solvents |
| Ph | Strongly alkaline in solution |
| Flashpoint | Flammable; flash point depends on ethanol content (about 12 °C for common ethanolic solutions) |
| Storageconditions | Store in a cool, dry, well-ventilated area under inert gas; protect from moisture, air, acids, and ignition sources |
| Hazardclassification | Corrosive; flammable; moisture-sensitive |
| Purity | Typically 95% solid or 20% w/w in ethanol, depending on grade |
| Unnumber | UN 3274 (alcoholates solution, n.o.s.) or UN 3206 (alkali metal alcoholates, self-heating, corrosive, n.o.s.) |
As an accredited Potassium Ethoxide factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Moisture-sensitive Potassium Ethoxide supplied in a 100 g amber glass bottle with PTFE-lined cap, sealed under inert gas. |
| Container Loading (20′ FCL) | Moisture-sensitive Potassium Ethoxide securely packed, sealed, and loaded into a 20-foot FCL container under hazardous cargo transport regulations and documentation. |
| Shipping | Potassium ethoxide is typically shipped as a hazardous, water-reactive corrosive alcohol solution. Common classification: UN 3274, Alcoholates solution, n.o.s. (Potassium ethoxide), Class 8, Packing Group II, with flammable subsidiary risk. Use sealed, moisture-resistant containers, keep dry, and label clearly. |
| Storage | Store potassium ethoxide in a cool, dry, well-ventilated area, away from moisture, acids, oxidizers, and ignition sources. Keep containers tightly closed, preferably under inert gas, and use corrosion-resistant, clearly labeled vessels. Protect from water because it reacts violently and is corrosive. Segregate from incompatible chemicals and follow local regulations for flammable/corrosive bases. Ensure secondary containment and spill kit availability. |
| Shelf Life | Potassium ethoxide: moisture/air-sensitive. Store sealed under inert gas, cool and dry. Typical shelf life 1–2 years. |
In fatty acid ethyl ester transesterification, potassium ethoxide supplied as a 20–24 wt% solution in anhydrous ethanol is metered into the oil–ethanol reactant stream downstream of the feedstock drying package. The catalytic charge is set at 0.8–1.2 wt% of oil mass for refined rapeseed, soybean or corn oil with free fatty acid content below 0.25 wt% and moisture below 0.3 wt%; the corresponding ethanol-to-oil molar ratio is maintained at 6.0:1–9.0:1. At these boundary conditions, potassium ethoxide is added as a homogeneous alkaline catalyst at 0.5–1.0 mol% relative to ester groups, with the exact charge corrected for feedstock acidity according to the acid number. The reaction is operated in a continuous stirred-tank reactor cascade or a single high-shear loop reactor at 65–75 °C; residence time ranges from 30–90 min depending on the number of reactor stages and target conversion above 97%. After reaction, the two-phase mixture is sent to a heated coalescer at 60–65 °C, where the glycerol phase is removed under 30–60 min retention time. The ester phase is washed in a countercurrent water-wash column with 0.1–0.5 wt% phosphoric acid at 55–65 °C to convert residual soaps into free fatty acids and salinity; this step also limits sodium/potassium carryover to below 5 ppm before vacuum drying. Residual ethanol is recovered in a falling-film evaporator at 80–90 °C and 18–25 kPa, followed by ester polishing through a recirculating vacuum distillation unit at 120–140 °C and 5–10 kPa. Finished fatty acid ethyl ester must comply with EN 14214:2012+A2:2019 for automotive B100 and ASTM D6751-23 for B100 blendstock; critical limit values include ester content ≥96.5 wt%, total glycerol ≤0.25 wt%, water content ≤500 mg/kg, and oxidation stability at 110 °C of ≥8 h under EN 14112. Terminal product types include fatty acid ethyl esters for heavy-duty diesel blending, heating oil replacements, biodegradable solvent esters, and lubricity additives.
| Parameter | EN 14214:2012+A2:2019 limit | ASTM D6751-23 limit |
|---|---|---|
| Total glycerol | ≤0.25 wt% | ≤0.240 wt% |
| Water content | ≤500 mg/kg | ≤0.050 vol% water and sediment |
| Ester content | ≥96.5 wt% | not specified |
Potassium ethoxide in pharmaceutical intermediate synthesis functions as a strong alkoxide base for deprotonation of active methylene substrates such as diethyl malonate, ethyl acetoacetate, and substituted arylacetonitriles. The reagent is introduced at 0–10 °C into a glass-lined vessel under nitrogen at 1.05–1.35 mol per mole of acidic substrate, with the internal temperature held below 25 °C during the exothermic enolate formation. This addition window is narrower than the biodiesel application because residual water above 500 ppm hydrolyzes potassium ethoxide to potassium hydroxide and ethanol, generating a mixed-base environment that increases unwanted saponification of ester functionality and reduces carbon–carbon bond selectivity. After enolate formation, the reaction is warmed to 25–60 °C and an alkyl chloride or bromide is metered over 2–4 h; total hold time is 4–12 h. Ethanol is then distilled at 40–50 °C under 20–25 kPa, and the residue is partitioned between toluene and water. The organic phase is washed with deionized water at 40–50 °C until chloride content determined by argentometric titration is below 50 ppm. Processing is governed by ICH Q7 for GMP intermediates, 21 CFR 211.160 for process validation, ICH Q3C for residual solvent class limits, USP <232> for elemental impurities, and REACH (EC) No 1907/2006 for registration of potassium ethoxide as an isolated intermediate feed. Terminal product types include substituted malonates and β-keto esters that enter downstream routes for central nervous system drugs, cardiovascular active substances, and nucleoside antiviral intermediates. Published data for specific molecular weight distributions and impurity profiles are limited and must be verified against the exact substrate matrix.
In agrochemical intermediate manufacture, potassium ethoxide is charged at 0.8–1.3 mol per mole of β-keto ester or β-diketone in refluxing anhydrous ethanol at 78–80 °C. The base abstracts the α-methylene proton, generating an enolate that attacks a substituted aryl hydrazine in a cyclocondensation sequence to form the pyrazole ring. The reaction is held at reflux for 2–6 h, then cooled to 10–20 °C and neutralized with acetic acid to pH 5.5–6.5; the resulting slurry is filtered through a plate-and-frame press and washed with chilled ethanol. Isolated wet cake is dried under vacuum at 45–55 °C to residual ethanol below 0.5 wt%. The technical active ingredient intermediates must comply with FAO/WHO specifications for technical grade material where relevant, CIPAC methods for assay and impurity profiling, EU Regulation (EC) No 1107/2009 for plant protection product registration, and 40 CFR Part 158 for residue chemistry data in the United States. This application demands tighter control of ethanol purity than the biodiesel route because trace aldehydes in denatured solvent can form hydrazones that consume the aryl hydrazine feedstock and decrease yield. Terminal product types produced from these intermediates include pyrazole fungicides, triazolone herbicides, and arylmethylpyrazole insecticide building blocks. Batch-to-batch variance is typically controlled by in-process HPLC with area percent target above 95%, but published data for specific matrix effects remain configuration-limited.
Benzaldehyde condensed with ethyl acetate over potassium ethoxide in anhydrous ethanol at 0–10 °C proceeds through a reversible Claisen–Schmidt addition followed by dehydration to ethyl cinnamate. The addition ratio is 0.10–0.30 mol potassium ethoxide per mole of benzaldehyde, with the benzaldehyde-to-ethyl acetate molar ratio set at 1.0:1.2–1.0:1.5 to suppress polymeric aldol side reactions. The reaction is carried out in a jacketed glass-lined reactor under nitrogen, and the potassium ethoxide solution is fed over 45–90 min while maintaining 5–15 °C; the mixture is then held for 3–6 h and quenched with acetic acid to pH 6.5–7.0. The aqueous phase is separated, and the crude organic phase is washed with saturated sodium chloride before vacuum fractional distillation at 140–145 °C and 1.3–1.6 kPa. Recovery of unreacted ethyl acetate is performed under reduced pressure at 40–50 °C. The isolated ethyl cinnamate contains residual benzaldehyde below 0.1 wt% when the final cut is controlled by refractive index at 20 °C of 1.559–1.561. For fragrance and flavor applications, the finished ester must comply with EU Regulation (EC) No 1334/2008 for flavoring substances, IFRA 49th Amendment for fragrance safety, and FEMA GRAS for food-grade uses where applicable. Terminal product types include cinnamon-like fragrance esters for fine perfumery, confectionery flavor components, and intermediates for cosmetic esterification reactions. The primary operational boundary is the exclusion of alkaline water washes before distillation; residual alkali above 0.05 wt% promotes ester hydrolysis and generates benzaldehyde as a retro-aldol impurity.
For biodegradable polyester production, potassium ethoxide is used as an anionic initiator at 0.1–1.0 mol% relative to ε-caprolactone monomer. The polymerization is conducted in bulk at 120–140 °C under mechanical stirring and vacuum 0.1–1.0 kPa for 4–12 h; the target number-average molecular weight is controlled by the monomer-to-initiator ratio, typically 100:1–1000:1. The monomer charge is dried over calcium hydride and distilled under reduced pressure until water content is below 50 ppm; reactor headspace oxygen is maintained below 100 ppm to prevent chain termination. After polymerization, the melt is discharged through a gear pump into an acidified tetrahydrofuran bath to remove potassium residues. The polymer is then precipitated into cold methanol at 0–5 °C and vacuum-dried at 40–50 °C. Compliance for medical and pharmaceutical intermediates includes ISO 10993-5 for in vitro cytotoxicity, ISO 13485 for device quality management, and USP <661> for plastic packaging suitability; if the final polyester is intended for food-contact applications, 21 CFR 177.1210 may apply. Terminal product types made from these polyesters include polycaprolactone microspheres for controlled-release drug delivery, suture coating films, bioresorbable implant components, and polyurethane soft segments. Published data for the rate of ε-caprolactone conversion under industrial-scale potassium ethoxide initiation are limited, and kinetic parameters should be validated against the specific monomer lot because trace α-acetylcaprolactone can deactivate the initiator.
Competitive Potassium Ethoxide prices that fit your budget—flexible terms and customized quotes for every order.
For samples, pricing, or more information, please contact us at +8615380400285 or mail to sales2@ascent-chem.com.
We will respond to you as soon as possible.
Tel: +8615380400285
Email: sales2@ascent-chem.com
Flexible payment, competitive price, premium service - Inquire now!
Potassium ethoxide (CAS 917-58-8; linear formula C₂H₅KO; molecular weight 84.16 g mol⁻¹) is supplied as a white to pale yellow solid and as a 24 wt% solution in anhydrous ethanol. The solid is a strongly basic alkoxide used where the ethoxide anion is required without introducing alkali-metal hydroxide; commercial certificates of analysis define the product by acid-base titration against 0.1 N hydrochloric acid, with assay values for KOC₂H₅ ordinarily falling between 95.0% and 99.0%. The ethanolic solution is specified at 23.5–24.5 wt% potassium ethoxide, and its water content is determined by Karl Fischer titration according to ASTM E203-16. Water above the supplier limit hydrolyzes the alkoxide to potassium hydroxide and ethanol, reducing the active catalytic species and changing the base strength. The solid is packaged in moisture-barrier polyethylene liners inside steel or fibre drums, while the solution is filled into UN-approved steel or high-density polyethylene drums because the ethanol vehicle is flammable. A harmonized product model is not used across manufacturers; the material is ordered by physical form and assay, commonly as solid grade ≥98% KOC₂H₅ or solution grade 24% in ethanol.
In ethanol-based biodiesel processes, potassium ethoxide is introduced as a homogeneous alkaline catalyst to provide the ethoxide anion that participates in carbonyl addition at the triglyceride backbone and is regenerated from ethanol during the catalytic cycle. The catalyst is metered as a 24 wt% ethanolic solution into the alcohol feed before mixing with triglycerides. Reaction temperatures in continuous stirred-tank or plug-flow configurations are maintained at 60–80 °C, and catalyst loading is optimized between 0.5 wt% and 1.5 wt% relative to the oil feed. Free fatty acid and water limits are held below 0.5% and 0.2%, respectively, to avoid excessive soap generation. A production-scale failure mode observed on multi-product plants is localized gelation and soap deposition on heating surfaces when concentrated catalyst solution meets high-phospholipid oil without adequate shear; the resulting heat-transfer fouling requires shutdown and alkaline wash. Static mixers or rotor-stator devices downstream of the catalyst injection point are used to achieve dispersion. Excess ethanol is required to shift the equilibrium, with typical ethanol-to-oil molar ratios between 6:1 and 20:1; recovered ethanol must be dried before reuse. The replacement of sodium methoxide with potassium ethoxide in ethanol-based transesterification eliminates methanol carry-over from the catalyst stream, and residual methanol in the final ester can be monitored by gas chromatography according to EN 14110. Final ethyl ester is checked against ASTM D6751; where the process is operated with methanol, EN 14214 applies to the methyl ester. Soap content is measured by AOCS Cc 17-95. Published data specific to potassium ethoxide-catalyzed continuous ethanolysis is limited compared with sodium methoxide, so pilot-scale calibration is required to establish yield and soap balance.
Potassium ethoxide is charged under inert atmosphere in pharmaceutical and agrochemical intermediate synthesis to mediate Claisen condensations, Dieckmann cyclizations, and alkylation of active methylene substrates. The reaction mass is usually maintained at −10 °C to 0 °C during enolate formation in ester condensation steps to limit over-alkylation and self-condensation. Because the potassium cation is more weakly associated than sodium in ethanolic media, enolate reactivity can be higher; the base is therefore introduced through a subsurface dip pipe or metering pump over a controlled period to avoid thermal excursions. Glass-lined reactors with nitrogen inerting are common, and moisture in the solvent is controlled by molecular-sieve drying or by specifying water below 0.1%. Residual protic impurities alter the alkoxide/hydroxide equilibrium and can broaden impurity profiles in downstream crystallization, so raw solvents are pre-dried and the headspace is kept under dry nitrogen. The material is also used in agrochemical routes to substituted pyrazole and pyrimidine intermediates, although exact process windows are generally restricted to patent and trade documentation.
Solid potassium ethoxide is hygroscopic and reacts exothermically with water; charging is therefore conducted under dry nitrogen or argon with a supply dew point below −40 °C. The powder is transferred from moisture-barrier drums through a split-valve containment system or weighed inside a glovebox to prevent contact with ambient air above 30% RH. Dissolution in ethanol is exothermic, and the rate of addition is controlled so that the reaction mass remains below 78.4 °C, the normal boiling point of ethanol; a jacketed glass-lined reactor with a chilled-water or brine circulator is used for larger batches. Batch records from multi-product plants identify static discharge and clumping of partially hydrolyzed powder as the main mechanical failure modes; rotary valves and flexible screw conveyors must be nitrogen-blanketed and bonded. The solid form is often avoided in favor of the 24 wt% ethanolic solution to eliminate dust exposure and reduce manual charging time. Where solid charging is unavoidable, the powder is added slowly to a vortex created by an agitator at low tip speed, and the reactor is vented to a caustic scrubber to capture ethanol vapor. Published particle size distribution data for potassium ethoxide powder is limited; milling is performed by the supplier to reduce lump formation, but the resulting particle size must be evaluated against the specific charging equipment.
Storage for the solid requires a cool, dry, and well-ventilated area with the original container kept tightly closed under inert gas. The ethanolic solution is highly flammable; ethanol has a closed-cup flash point of 13 °C under ISO 2719 and is classified as H225 highly flammable liquid under CLP. Potassium ethoxide itself is classified as skin corrosive H314 and causes serious eye damage H318; REACH-compliant safety data sheets specify butyl rubber or neoprene gloves, chemical goggles, and face shields for handling. Incompatibilities include water, aqueous acids, strong oxidizers, and halogenated solvents. Contact with moisture generates potassium hydroxide, which can concentrate in container headspace and corrode unlined steel. The solution grade should not be exposed to direct sunlight or ambient temperatures above 35 °C; spillage of solid must be collected under dry conditions and neutralized with dilute acid by trained personnel. Water spray must not be applied directly because hydrolysis is exothermic and can generate ethanol vapor. Flammable-liquid storage cabinets conforming to NFPA 30 or equivalent local fire codes are used for the ethanolic solution, and the vapour space should be inerted to an oxygen concentration below 8 vol% during tank storage.
The table summarizes representative acceptance limits from supplier certificates of analysis. These values are not harmonized and must be confirmed against the specific grade used.
| Parameter | Solid grade | 24 wt% ethanolic solution | Analytical procedure |
|---|---|---|---|
| Assay as KOC₂H₅ | 95.0–99.0% | 23.5–24.5 wt% | Acid-base titration, 0.1 N HCl |
| Water content | ≤ 0.5% | ≤ 0.2% | ASTM E203-16 |
| Free alkali as KOH | ≤ 2.0% | ≤ 0.5% | Potentiometric titration |
| Color, APHA | not specified | ≤ 100 | ASTM D1209-05(2019) |
| Ethanol assay | residual by headspace GC | balance, anhydrous | Gas chromatography |
Assay by titration is interpreted alongside the free alkali value, because both ethoxide and hydroxide consume acid. The solution grade is additionally checked for insoluble matter by filtration through a 0.45 µm membrane and for trace sodium by inductively coupled plasma optical emission spectrometry where cation purity is specified. Solid material may contain residual ethanol that contributes to the organic carbon content; headspace gas chromatography is used to quantify residual ethanol and to verify packaging integrity after storage.
When potassium ethoxide is compared with sodium ethoxide, the mass required for equal molar charge is higher by a factor of 1.24, based on molecular weights of 84.16 g mol⁻¹ and 68.05 g mol⁻¹. The potassium cation has an ionic radius of approximately 138 pm in six-coordinate environments, compared with 102 pm for sodium; this larger radius reduces ion-pair association in ethanol and can increase the effective basicity of the ethoxide anion in non-aqueous media. In Claisen condensation runs, the change may allow a lower molar excess of base but can also accelerate exothermic oligomerization, so pilot trials are required. Potassium ethoxide and sodium ethoxide share the same ethoxide anion, so the aqueous pKa of the conjugate acid ethanol is 15.9 for both; selectivity differences arise from cation effects and solubility rather than conjugate-acid strength. Potassium tert-butoxide, by contrast, has a sterically hindered tertiary alkoxide and a conjugate acid pKa near 19.2, making it a stronger base for E2 eliminations but a poorer nucleophile for substitution at carbon. The following table compares the three alkoxides.
| Property | Potassium ethoxide | Sodium ethoxide | Potassium tert-butoxide |
|---|---|---|---|
| Molecular weight | 84.16 g mol⁻¹ | 68.05 g mol⁻¹ | 112.21 g mol⁻¹ |
| Cation ionic radius, six-coordinate | 138 pm | 102 pm | 138 pm |
| Alkoxide steric bulk | low | low | high |
| Conjugate alcohol pKa, water | 15.9 | 15.9 | 19.2 |
| Common solution form | 24 wt% in ethanol | 21 wt% in ethanol | 1.0 M in tetrahydrofuran |
Potassium ethoxide is less commonly supplied as a tetrahydrofuran solution because reactions requiring ethoxide are usually run in ethanol. The replacement of potassium tert-butoxide with potassium ethoxide changes both steric and basicity profiles; ethoxide-mediated condensations and substitutions are favored when the target pathway requires a primary alkoxide nucleophile, while tert-butoxide is retained for sterically directed eliminations. The final selection is based on the desired reaction pathway, solvent, and the acceptable level of residual potassium in the downstream product, where potassium is quantified by inductively coupled plasma optical emission spectrometry according to USP <233> or an equivalent compendial method.
