| HS Code | 456000 |
| Name | Malonic acid |
| Iupac Name | Propanedioic acid |
| Chemical Formula | C3H4O4 |
| Molar Mass | 104.06 g/mol |
| Cas Registry Number | 141-82-2 |
| Ec Number | 205-503-0 |
| Pubchem Cid | 867 |
| Appearance | White crystalline solid |
| Odor | Odorless |
| Density | 1.619 g/cm³ |
| Melting Point | 135–137 °C |
| Boiling Point | Decomposes at 140 °C |
| Solubility In Water | 73 g/100 mL at 20 °C |
| Solubility In Ethanol | Soluble |
| Solubility In Ether | Soluble |
| Acidity | Diprotic acid |
| Flash Point | 157 °C |
| Decomposition | Decomposes on heating to acetic acid and carbon dioxide |
As an accredited Malonic Acid factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Malonic Acid packaged in a 500 g amber glass bottle with secure chemical-resistant cap and GHS-compliant labeling. |
| Container Loading (20′ FCL) | Malonic acid, packaged in bags or drums on pallets, loaded into a clean, dry 20′ FCL container, secured and labeled for transport. |
| Shipping | Malonic acid is shipped as a non-hazardous solid in sealed, labeled containers. It is not classified as dangerous goods for DOT, IATA, or IMDG transport. Store and ship dry, cool, and away from oxidizers and bases. Follow all local precursor and chemical shipping regulations. |
| Storage | Store malonic acid in a cool, dry, well-ventilated area in a tightly closed, labeled container. Protect from moisture, heat, and ignition sources. Keep separate from strong bases, oxidizing agents, and incompatible materials. Use corrosion-resistant containers and secondary containment where required. Maintain good housekeeping and follow SDS/local regulations. Avoid dust generation and keep away from food, drink, and animal feed. |
| Shelf Life | Malonic acid is stable; shelf life is about five years when stored dry, sealed, at room temperature, away from moisture. |
Pharmaceutical-grade malonic acid is charged as the C3 backbone source after conversion to diethyl malonate, rather than as a direct final-dose intermediate. In a typical esterification, malonic acid is charged into a glass-lined reactor with ethanol at a molar ratio of 1:2.2–1:2.6, with 0.5–1.0 wt% sulfuric acid or 0.3–0.7 wt% p-toluenesulfonic acid on malonic acid mass as catalyst. The jacket is held at 78–85°C, and water is removed by azeotropic distillation through a Dean-Stark trap or cyclohexane entrainer. After neutralization with aqueous sodium bicarbonate to pH 7.0–7.5, the crude ester is washed with deionised water, dried under vacuum, and purified in a packed-column still at 10–20 mbar with a vapour temperature of 75–82°C. The recovered diethyl malonate is then condensed with urea in a sodium ethoxide/ethanol system at a diethyl malonate-to-urea molar ratio of 1:1.0–1:1.05 and sodium ethoxide at 1.0–1.5 mol per mol diethyl malonate. The reaction mass is held at 78–80°C for 6–8 h; residual water above 0.2% in the ethanol system suppresses the condensation and lowers barbituric acid yield. The precipitated sodium barbiturate is dissolved in process water, filtered through a 0.45 µm polish filter, and acidified with hydrochloric acid to pH 2.0–2.5; the product is isolated by centrifuge and dried in a vacuum tray dryer at 55–65°C. This route supplies barbituric acid (CAS 67-52-7) as an isolated or non-isolated intermediate for phenobarbital and primidone manufacture. Compliance for the intermediate stage follows ICH Q11; API producers align residual-solvent limits with USP <467>, Ph. Eur. 2.4.24, and ICH Q3C, and equipment qualification follows EU GMP Annex 15. Terminal product types are barbiturate-class APIs, including phenobarbital and primidone, which are subject to end-use controls in many jurisdictions.
In autocatalytic nickel-phosphorus plating lines, malonic acid is introduced as a dicarboxylate complexing agent and pH buffer in the working bath; it is not consumed stoichiometrically but its concentration is depleted by drag-out and bath bleed. The bath is built with 5.0–7.0 g/L nickel sulfate hexahydrate, 20–30 g/L sodium hypophosphite monohydrate, and 12–35 g/L malonic acid on an anhydrous basis. The pH is held at 4.5–5.2 using 50% ammonium hydroxide or 10% sulfuric acid; bath temperature is 85–90°C. A typical plating line for automotive fuel rails uses 316L stainless steel tanks with continuous filtration through 1–5 µm polypropylene cartridges and low-pressure air agitation. Within this window, the deposition rate is 12–20 µm/h; internal stress and phosphorus content respond to malonic acid concentration. Below 10 g/L, the bath loses buffering capacity and pH drift accelerates, increasing the risk of nickel hydroxide precipitation; above 40 g/L, complexation becomes too strong, lowering plating rate and causing edge-skip on threaded geometries. The process sequence includes alkaline soak cleaning, reverse electroclean, 10–15 vol% HCl immersion, a Woods nickel strike for stainless steel substrates, then the autocatalytic nickel step. Post-treatment includes rinse, 1–3% chromate passivation or Cr-free passivation, and rack stripping. This operation is covered by ASTM B733-15 and ISO 4527:2003 for autocatalytic nickel-phosphorus coatings on metals; automotive parts are assessed against RoHS 2011/65/EU and ELV 2000/53/EC. Terminal product types include API 6A gate valves, pump volutes, automotive fuel-injection rails, and downhole tubing hangers.
| Parameter | Range | Measurement method |
|---|---|---|
| Malonic acid, anhydrous basis | 12–35 g/L | HPLC or ion chromatography |
| Nickel sulfate hexahydrate | 5.0–7.0 g/L | EDTA titration |
| Sodium hypophosphite monohydrate | 20–30 g/L | Iodometric titration |
| pH | 4.5–5.2 | Calibrated pH meter |
| Bath temperature | 85–90°C | PT100 thermocouple |
| Deposition rate | 12–20 µm/h | X-ray fluorescence or gravimetric |
| Bath turnover | 4–6 MTO | Metal turnover calculation |
Diethyl malonate produced from malonic acid is condensed with guanidine carbonate to give 2-amino-4,6-dihydroxypyrimidine, a pyrimidinyl intermediate used in sulfonylurea and triazolopyrimidine herbicide campaigns. The charge ratio is 1.0 mol diethyl malonate to 1.03–1.08 mol guanidine carbonate; sodium methoxide is charged at 1.8–2.2 mol per mol diethyl malonate, and methanol is added at 6–8 volumes relative to diethyl malonate. The reaction is exothermic during initial addition; the jacket is held at 40–50°C for the first 30–60 min, then the mass is brought to reflux at 64–68°C for 6–8 h. Methanol is recovered under vacuum, the residue is dissolved in water, and pH is adjusted to 5.5–6.5 with 30% hydrochloric acid. The resulting slurry is filtered on a plate-and-frame or agitated nutsche filter, washed with deionised water, and dried in a rotary vacuum dryer at 60–70°C. Conversion and impurity profiles are monitored by HPLC; a typical specification limits unreacted diethyl malonate below 0.5 area%. Compliance is not defined by a single pharmacopoeial monograph because the intermediate is not a finished active; producers align with REACH Regulation (EC) No 1907/2006 registration dossiers and EU 1107/2009 data requirements when the downstream active is placed on the Union market. Biodegradability screening may be conducted according to OECD 301. Terminal product types are herbicidal actives in the sulfonylurea class and related triazolopyrimidine actives, usually formulated as wettable granules, suspension concentrates, or oil dispersions.
For synthetic fruit-note compositions, diethyl malonate derived from malonic acid is handled as a vacuum-rectified aroma chemical rather than as a bulk ester. The ester is prepared by acid-catalysed esterification of malonic acid with ethanol, followed by neutralisation with 10% sodium carbonate, water washing, drying over anhydrous sodium sulfate, and fractional distillation under 20–25 mmHg at a vapour temperature of 95–100°C. Product used in flavour applications is controlled to 99.0% minimum purity, with acid value below 1.0 mg KOH/g and moisture below 0.1%. In fruit-flavour compounding, diethyl malonate is added at 0.2–2.5 wt% of the flavour concentrate; the final use level in ready-to-consume food or beverage is 5–50 ppm, depending on the matrix and desired profile. In fragrance compounds, the addition ratio is 0.5–3.0 wt% when a rounded apple-pear lift is required. Regulatory status is anchored to U.S. 21 CFR 172.515 as a synthetic flavouring substance permitted under FDA GMP, EU 1334/2008/EC for flavourings, and the JECFA/FEMA listing as FEMA 2375. For fragrance use, the material is assessed under IFRA Standards if the finished mixture is intended for skin-contact applications; the CAS registry number is 105-53-3. Downstream processing includes high-shear dispersion into propylene glycol or triacetin carriers for water-phase flavour delivery, or direct blending into alcoholic fragrance bases at 15–25°C. Terminal product types include apple, pear, and melon flavour bases for beverages and bakery fillings, as well as fine-fragrance and personal-care fragrance oils.
In copper damascene chemical mechanical planarization, malonic acid is used as a pH buffer and cupric ion complexing agent. The slurry is formulated with 0.2–1.5 wt% malonic acid, 0.5–2.0 wt% hydrogen peroxide as oxidiser, 1–5 wt% colloidal silica or alumina abrasive, and 0.05–0.3 wt% benzotriazole as a copper corrosion inhibitor. The pH is adjusted to 2.5–4.0 with ammonium hydroxide or nitric acid; slurry viscosity is typically 1.5–2.5 cP at 25°C. Polishing is carried out on a 300 mm CMP tool with a downforce of 1.5–3.0 psi, platen speed of 30–90 rpm, head speed of 30–90 rpm, and slurry flow of 100–200 mL/min. Removal rate and within-wafer non-uniformity are measured by 49-point sheet-resistance metrology; a typical target for copper removal is 3000–6000 Å/min with a static etch rate below 50 Å/min. The addition of malonic acid above 2.0 wt% can depress removal rate and increase post-CMP corrosion defects if benzotriazole is not adjusted. Suppliers of malonic acid for CMP are expected to control total trace metal impurities to ≤1 ppm for key transition metals such as iron, copper, and nickel, with a certificate of analysis per lot. Process control is aligned with SEMI S2 and SEMI S8 for equipment safety, and cleanroom operations follow ISO 14644-1 Class 1–5. Published data for malonic acid-specific slurry interactions remain limited because commercial slurry formulations are proprietary. Terminal product types are copper interconnects in logic and memory devices, advanced packaging redistribution layers, and through-silicon via structures.
Competitive Malonic Acid 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!
Malonic acid, CAS 141-82-2, is the C3 α,ω-dicarboxylic acid with the formula CH2(COOH)2 and molar mass 104.06 g/mol. The product is supplied as a white to off-white crystalline powder. Commercial models are differentiated by anhydrous assay and residual ionic content: technical grade commonly meets 98.5% minimum purity, synthesis grade 99.0% minimum, and high-purity grade 99.5% minimum. Certificates of analysis for high-purity material generally report loss on drying by ISO 760 Karl Fischer titration at ≤0.50%, residue on ignition at ≤0.05% after 600 °C combustion, and a melting range of 135.0 °C to 137.0 °C. Packaging consists of 25 kg HDPE bags with moisture-barrier liners, 500 kg FIBC, or 1000 kg FIBC. The material is freely soluble in water, methanol, and ethanol. Aqueous pKa values are 2.83 and 5.70 at 25 °C.
Derivative models supplied alongside the free acid include dimethyl malonate, CAS 108-59-8, and diethyl malonate, CAS 105-53-3. The free acid is specified for aqueous pH adjustment, salt formation, or direct condensation where water removal is not a constraint. The esters are specified for anhydrous enolate alkylation and Knoevenagel condensation because they avoid carboxylate salt formation and reduce water content in polar aprotic media.
Specification control for the free acid depends on the downstream unit operation. For esterification trains using solid acid catalysts, chloride is controlled to ≤50 mg/kg because chloride accelerates pitting in stainless steel reboilers. Sulfate is controlled to ≤100 mg/kg to limit sulfonate side products. Iron is controlled to ≤5 mg/kg for colour-sensitive pharmaceutical intermediates. These parameters are measured by ion chromatography and ICP-OES.
The structural difference is a geminal dicarboxyl arrangement. The central methylene unit is flanked by two carbonyl groups, producing an active methylene with elevated acidity and enabling enolate chemistry that succinic, glutaric, and adipic acids cannot replicate. This geometry also lowers thermal stability relative to the higher linear dicarboxylic acids. Table 1 compares the properties that direct substitution decisions.
Table 1. Comparative data for linear dicarboxylic acids commonly evaluated against malonic acid.
| Property | Malonic acid | Succinic acid | Glutaric acid | Adipic acid |
|---|---|---|---|---|
| CAS RN | 141-82-2 | 110-15-6 | 110-94-1 | 124-04-9 |
| Molecular formula | C3H4O4 | C4H6O4 | C5H8O4 | C6H10O4 |
| Molar mass | 104.06 g/mol | 118.09 g/mol | 132.12 g/mol | 146.14 g/mol |
| pKa1 / pKa2 | 2.83 / 5.70 | 4.16 / 5.61 | 4.31 / 5.41 | 4.43 / 5.41 |
| Melting range | 135–137 °C with decomposition | 188–190 °C | 97.5–99 °C | 152–154 °C |
| Active methylene | Present | Absent | Absent | Absent |
| Key downstream chemistry | Malonic ester synthesis, Knoevenagel, barbituric acid | Polybutylene succinate, succinimide | Glutarate esters, dibasic ester solvents | Nylon 6,6 salt, adipate plasticizers |
Malonic acid is occasionally confused with malic acid, CAS 617-48-1, but the two differ by functionality. Malic acid contains a hydroxyl group on the carbon bearing one carboxyl group, whereas malonic acid has no hydroxyl group. This distinction matters in polyester formulations because malic acid introduces branching through the hydroxyl site while malonic acid yields only linear diester linkages.
Esterification of malonic acid with ethanol under acid catalysis yields diethyl malonate. The α-methylene pKa in diethyl malonate is approximately 13, which permits deprotonation with sodium ethoxide in anhydrous ethanol. Alkylation is conducted at 0 °C to 30 °C with primary alkyl halides; secondary alkyl halides require longer residence times and temperatures up to 50 °C. After saponification and acidification, the substituted malonic acid is decarboxylated at 140 °C to 180 °C. The CO₂ volume released is approximately 215 m³ per tonne of malonic acid at 0 °C and 101.325 kPa, based on stoichiometry.
In pharmaceutical heterocycle production, diethyl malonate is generally preferred over malonic acid because the ester is soluble in anhydrous ethanol and avoids water generated by salt formation. Condensation with urea in the presence of sodium ethoxide produces barbituric acid derivatives after acidification and crystallization. Plant-scale vessels for this transformation are glass-lined and fitted with reflux condensers and scrubbers sized for ammonia and carbon dioxide release.
Technical-grade malonic acid is also used as a C3 building block in agrochemical intermediates through Knoevenagel condensation with aromatic aldehydes. The reaction is run in toluene or cyclohexane at reflux with a secondary amine catalyst; water is removed by a Dean-Stark trap. The resulting alkylidenemalonate is reduced or decarboxylated to yield substituted acrylic acid derivatives. Production-scale vessels are equipped with packed distillation columns for solvent recovery and with nitrogen blanketing to limit colour formation from aldehyde oxidation.
Malonic acid–based polyester polyols are evaluated for high-solids and waterborne two-component polyurethane systems. Condensation with diethylene glycol at 160 °C to 180 °C using dibutyltin oxide at 0.05 wt% to 0.20 wt% produces oligomeric diols with acid numbers below 5 mg KOH/g after 12 h. The malonate unit reduces crystallinity relative to succinate-based polyols; however, thermal decomposition limits the upper processing temperature. Film tensile specimens are tested by ASTM D638-14, and pendulum hardness by ASTM D4366-16. Published data for this specific malonate-diol configuration is limited, so batch qualification is required.
The main operational boundary is the low decarboxylation temperature. Differential scanning calorimetry at 10 K/min under nitrogen resolves melting at 135–137 °C with immediate endothermic weight loss. Closed reactors must be protected against CO₂ generation. A 1 m³ molten charge can release approximately 380 m³ of CO₂ at 25 °C and 101.325 kPa if decarboxylation proceeds to acetic acid. Emergency relief sizing should follow ASME BPVC Section VIII or ISO 4126-10; vacuum systems should include alkali scrubbers because CO₂ reduces pump efficiency.
Bulk storage should be maintained at ≤25 °C and ≤60% relative humidity. At RH greater than 60%, surface moisture causes crystal bridging and increases cohesive discharge problems in FIBC. Vibratory bin activators or low-friction liners are specified for silo discharge. Convection drying should not exceed 60 °C for malonic acid, whereas succinic acid can tolerate higher drying temperatures. Shelf life is commonly assigned at 24 months from production date when stored in unopened original packaging.
Quality systems for malonic acid are typically managed under ISO 9001; production sites may also maintain ISO 14001 and ISO 45001 certifications. REACH registration is maintained by EU suppliers, and supply chain documentation includes a safety data sheet under Regulation (EC) No 1907/2006. Users should confirm that the specific grade meets residual solvent requirements for pharmacopeial or food-contact applications, because technical routes may leave trace methanol or ethanol. Oxidative stability screening by differential scanning calorimetry may be used to detect peroxidic contaminants; malonic acid itself is not classified as a peroxide former.
Compared with succinic acid, malonic acid offers stronger acidity and lower esterification viscosity but requires tighter temperature control. Compared with glutaric acid, malonic acid provides a shorter C3 spacer in polymer backbones and avoids the characteristic odour of glutaric acid. Compared with adipic acid, malonic acid delivers higher oxygen content per mole and lower hydrocarbon chain length, which alters hydrolytic resistance and glass transition. Selection among these acids should be based on the targeted chain segment length, thermal budget, and required active methylene reactivity.
