Section
| HS Code | 138213 |
| Productname | Dipentaerythritol |
| Casregistrynumber | 126-58-9 |
| Einecsnumber | 204-794-1 |
| Molecularformula | C10H22O7 |
| Molecularweight | 254.28 g/mol |
| Appearance | White crystalline powder |
| Purity | ≥98% |
| Meltingpoint | 215-218 °C |
| Boilingpoint | 356.2 °C at 760 mmHg (estimated) |
| Density | 1.3 g/cm³ (estimated) |
| Hydroxylvalue | 1320-1330 mg KOH/g |
| Watersolubility | Slightly soluble in water |
| Moisture | ≤0.5% |
| Ashcontent | ≤0.1% |
As an accredited Dipentaerythritol factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Dipentaerythritol is packaged in 25 kg net multiwall paper bags with moisture-barrier liners, stacked on pallets for industrial shipment. |
| Container Loading (20′ FCL) | Dipentaerythritol in 25 kg bags is palletized and securely stowed in a 20′ FCL container with moisture protection for ocean transport. |
| Shipping | Dipentaerythritol is typically shipped as a non-hazardous solid in fiber drums, bags, or supersacks with moisture-protective liners. It is generally not regulated as dangerous goods under DOT/IMDG/IATA in normal form. Label with product identity, keep dry, and follow the supplier SDS and local regulations. |
| Storage | Store dipentaerythritol in a cool, dry, well-ventilated area in tightly closed, labeled containers, away from direct sunlight, heat, ignition sources, and moisture. Protect from physical damage. Keep separate from strong oxidizers and acids. Avoid dust generation and accumulation; use grounded equipment and good housekeeping. Do not store near food, drink, or animal feed, and follow local regulations and the manufacturer’s SDS. |
| Shelf Life | Dipentaerythritol generally has a shelf life of about two years if stored cool, dry, sealed, and away from moisture. |
In alkyd resin synthesis, dipentaerythritol functions as a hexafunctional neopentyl polyol whose two quaternary carbon centers and central ether bridge force six primary hydroxyl groups into a spatially separated configuration. In high-solids bake enamels formulated at 70–75% non-volatile content, dipentaerythritol is charged at 8–15 wt% of total resin solids, typically replacing 20–35 mol% of the glycerol or pentaerythritol fraction. The resin reactor is a stainless-steel vessel with partial condenser, xylene azeotropic water knockout, and variable-frequency agitator; cook temperature is maintained at 230–245 °C, and the hydroxyl excess is held at 10–25% relative to the calculated acid value endpoint. Production batches are terminated when acid value falls below 10 mg KOH/g and the cut at 60% solids in xylene reaches Gardner-Holdt viscosity V–Z. If the dipentaerythritol fraction exceeds 18 wt%, gel-permeation chromatography shows a high-molecular-weight tail after xylene reduction, which can produce transfer viscosity drift on coil coating lines. Terminal products include coil coating primers on 0.5–0.8 mm galvanized steel, automotive basecoat intermediates, and general industrial bake enamels cured at 140–160 °C. Regulatory anchors include EU Directive 2004/42/EC for industrial bake coatings, FDA 21 CFR 175.300 for routine food-contact can ends, ASTM D2369-10 for volatile organic compound determination, and ISO 12944-6 for C3–C4 atmospheric corrosivity classifications.
Rosin ester reactors equipped with gas-fired or thermal-oil heating, overhead decanter, and high-vacuum stripping are used for the esterification of gum rosin or disproportionated rosin with dipentaerythritol at 9–12 wt% of the rosin feed. The reaction is staged at 270–285 °C under nitrogen until the acid value drops below 15 mg KOH/g, after which vacuum stripping at <2 kPa removes low-molecular-weight rosin acids and esterification water. Dipentaerythritol raises the softening point of the ester by 8–15 °C relative to glycerol esters at the same acid value, but this is accompanied by a non-linear increase in melt viscosity; in production-scale blending tanks this requires holding the tackifier at 160–170 °C during adhesive compounding to maintain pumpability and avoid char in hot-melt applicator nozzles. In styrenic block copolymer hot-melt formulations, the dipentaerythritol rosin ester is dosed at 30–50 wt% alongside 20–30 wt% SBC polymer and 15–25 wt% naphthenic or paraffinic oil. The terminal product range includes pressure-sensitive label adhesives, bookbinding hot-melts, and polyamide-based reactive assembly adhesives. Regulatory anchors include FDA 21 CFR 175.105 for finished adhesives and FDA 21 CFR 175.125 for pressure-sensitive adhesives, as well as softening point testing per ASTM D6493 and melt viscosity per ASTM D3236.
At 25 °C, dipentaerythritol penta/hexa-acrylate is a high-solids liquid crosslinker with viscosity typically in the range of 10,000–18,000 mPa·s, depending on the penta/hexa ester ratio and inhibitor content. In clear hard-coat formulations, dipentaerythritol penta/hexa-acrylate is incorporated at 5–20 wt% of the wet coating mass to increase crosslink density; in stereolithography or digital light processing resins it is used at 10–35 wt% to balance green strength and curl. The formulating sequence uses high-shear mixing at 1,000–2,500 rpm with a Cowles blade or planetary mixer at 25–35 °C to avoid thermal polymerization; a free-radical photoinitiator package, typically bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide or a phenylphosphine oxide blend, is added at 0.5–3 wt%. Curing on flatbed UV lines requires 300–1,000 mJ/cm² in the UVA or UV-LED 395 nm window, but the surface oxygen inhibition threshold must be managed by nitrogen blanketing or a final LED array at 385 nm. Terminal products include optical fiber coatings, overprint varnishes, solder mask inks, and precision investment casting patterns produced by vat polymerization. Compliance citations include REACH Annex XVII for acrylate monomers, ISO 10993-5 for short-term body-contact printed devices, and EN 71-3 migration limits for consumer electronic coatings.
When compounded below 190 °C, dipentaerythritol-derived char precursors are dry-blended into polypropylene intumescent systems at 8–18 wt% as the carbon source, with ammonium polyphosphate at 20–25 wt% and melamine at 5–10 wt%, the residual being impact-modified polypropylene and processing aids. The twin-screw extruder used for this compound is typically a 40–75 mm co-rotating intermeshing machine with L/D 40:1 and barrel zones set at 160 °C, 170 °C, 180 °C, and 185 °C; a side feeder delivers the char former after the polymer melt seal to reduce dust and prevent pre-reaction with ammonium polyphosphate. Because dipentaerythritol begins to melt at 215–222 °C, compounding above 205 °C is avoided, and granulation is run with residual moisture below 0.1 wt% after an 80 °C pre-dry. The UL 94 vertical burn test at 1.6 mm is the primary pass criterion for V-0 compounds; ISO 5660-1 cone calorimetry at 35 kW/m² is used to record the peak heat release rate reduction and effective heat of combustion. Terminal product types include injection-molded appliance housings, cable conduit fittings, and intumescent mastics for steel construction. Regulatory anchors include RoHS 2011/65/EU, EN 45545-2 for rail interior materials, and the EU Construction Products Regulation as implemented through EN 13501-1.
For hermetic compressor lubricants, polyol ester base stocks derived from dipentaerythritol and branched C5–C9 acids are processed to an acid number below 0.05 mg KOH/g and a Karl Fischer moisture content below 50 ppm before additive treatment. The base ester is used at 95–100 wt% of the finished refrigeration oil, with a performance package of 1–3 wt% consisting of antioxidants, acid scavengers, and anti-wear additives; this loading is limited by the miscibility requirements with hydrofluorocarbon refrigerant blends such as R-134a and R-410A in circulation ratios up to 20% oil-in-refrigerant. Esterification is run at 220–240 °C with a titanium alkoxide catalyst at 0.01–0.05 wt%, followed by thin-film evaporation below 5 kPa and a 3 µm absolute filtration step to remove catalyst residues and reduce particulate contamination below ISO 4406 17/15/12. Terminal product types include ISO VG 68, 100, and 150 compressor oils for commercial refrigeration, heat pumps, and automotive AC compressors where high thermal stability at discharge temperatures above 150 °C is required. Compliance specifications typically cite DIN 51503-1 for refrigeration oils, ISO 6743-3 for lubricant classification, ASTM D445 for kinematic viscosity, ASTM D974 for acid number, and ASTM D6304 for water content.
Carboxyl-functional polyester resins for powder coatings are synthesized in a two-stage melt polycondensation sequence using dipentaerythritol at 5–12 wt% of the total monomer charge, alongside terephthalic acid, neopentyl glycol, and a small proportion of adipic acid or isophthalic acid to control crystallinity. The first stage is run at 230–250 °C under nitrogen until the acid value drops below 20 mg KOH/g; the second stage is carried out under vacuum at 1–3 kPa to drive the final acid value to 28–35 mg KOH/g and glass transition temperature to 58–68 °C. The resin is then flaked and extruded on a twin-screw extruder at 80–110 °C with TGIC or β-hydroxyalkylamide at 93:7 or 95:5 resin-to-curing-agent ratios; barrel temperatures exceed the resin glass transition but remain below the onset of premature crosslinking, typically 120 °C for TGIC systems. Powder coatings based on dipentaerythritol-branched polyester resins are applied electrostatically and cured at 180–200 °C for 10–15 min. Terminal product types include architectural aluminum extrusions, automotive underbody coatings, and heat-sensitive medium-density fibreboard finishes. Compliance is governed by Qualicoat Class 1 and Class 2 specifications, ISO 8130-6 for gel time, ASTM D3451 for coating powder testing, and RoHS 2011/65/EU for heavy-metal limits.
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Commercial dipentaerythritol is supplied as a white crystalline solid in flake or fine powder form and is assigned CAS 126-58-9. The molecule, 2,2′-[oxybis(methylene)]bis[2-(hydroxymethyl)propane-1,3-diol], has the formula C10H22O7 and a molar mass of 254.28 g/mol. Six primary hydroxyl groups are distributed across two neopentyl-terminated clusters linked by a central ether oxygen. Commercial model designations such as DPE 85, DPE 90, and DPE 95 indicate the minimum dipentaerythritol assay on a dry basis, with the remaining mass consisting principally of pentaerythritol, tripentaerythritol, and homologous polyol ethers. The product is selected for applications requiring a thermally stable hexafunctional building block: high-solids alkyds, saturated polyesters, rosin esters, UV-curable acrylates, intumescent carbonifics, and polyol ester lubricant basestocks.
The primary structural distinction is hydroxyl functionality: dipentaerythritol contains 6 primary hydroxyl groups per molecule, compared with 4 for pentaerythritol and 3 for trimethylolpropane. The central ether linkage raises molecular weight while retaining primary-neopentyl character, so esterification kinetics are not governed by secondary-hydroxyl selectivity. Hydroxyl equivalent weights are 42.38 g/equiv for dipentaerythritol, 34.04 g/equiv for pentaerythritol, and 44.72 g/equiv for trimethylolpropane. The higher equivalent weight of dipentaerythritol reduces the mass-based crosslink density contribution relative to pentaerythritol; however, the central ether bridge introduces a flexible spacer and reduces crystallinity in some cured films. Differential thermal behavior is also significant because dipentaerythritol melts at 210–225 °C, which alters reactor charging and melting profiles in batch resin production compared with lower-melting trimethylolpropane.
| Parameter | Dipentaerythritol | Pentaerythritol | Trimethylolpropane | Test method |
|---|---|---|---|---|
| CAS registry | 126-58-9 | 115-77-5 | 77-99-6 | — |
| Molar mass | 254.28 g/mol | 136.15 g/mol | 134.17 g/mol | — |
| Primary hydroxyl groups per molecule | 6 | 4 | 3 | — |
| Hydroxyl equivalent weight | 42.38 g/equiv | 34.04 g/equiv | 44.72 g/equiv | — |
| Theoretical hydroxyl value | 1324 mg KOH/g | 1648 mg KOH/g | 1254 mg KOH/g | ASTM D4274 |
| Melting range | 210–225 °C | 260–262 °C | 58–60 °C | capillary or differential scanning calorimetry |
Specification control for technical dipentaerythritol is built around assay, hydroxyl value, moisture, residue on ignition, and color. The assay is typically determined by gas chromatography after trimethylsilylation because underivatized dipentaerythritol has insufficient volatility for direct GC analysis. Hydroxyl value is commonly reported by ASTM D4274-21. Moisture is measured by ASTM D4672, color in the molten state by ASTM D1209, and residue on ignition in a muffle furnace at 800 °C. For a DPE 90 grade, representative public technical data list dipentaerythritol assay at 90.0 % minimum, hydroxyl value in the range of 1250–1330 mg KOH/g, moisture at 0.10 % maximum, and residue on ignition at 0.05 % maximum. Lower assay material is generally associated with higher pentaerythritol or tripentaerythritol content, which affects crosslink density, melt viscosity, and final resin color.
| Parameter | Typical range | Test method |
|---|---|---|
| Dipentaerythritol assay | 90.0 % minimum | GC-FID after trimethylsilylation |
| Hydroxyl value | 1250–1330 mg KOH/g | ASTM D4274-21 |
| Moisture | 0.10 % maximum | ASTM D4672 |
| Residue on ignition | 0.05 % maximum | muffle furnace 800 °C |
| Molten color | 50 APHA maximum | ASTM D1209 |
In high-solids alkyd cooking, dipentaerythritol is charged with dibasic acids or anhydrides and fatty acids in a reactor equipped with a partial condenser, reflux splitter, Dean-Stark trap, and anchor or turbine agitation. The esterification is acid-catalyzed and follows second-order kinetics with respect to residual carboxyl and hydroxyl concentrations above the melt phase. Because dipentaerythritol has a melting range of 210–225 °C, processing is conducted either as a melt or in an azeotropic solvent such as xylene to maintain homogeneous mass transfer. Typical reaction temperatures are 220–250 °C; operation above 250 °C accelerates color-body formation and can initiate ether-cleavage side reactions. The central ether oxygen does not participate as a reactive site under standard alkyd cook conditions, but it can be thermally stressed at elevated temperatures, which is one reason narrow temperature control is required.
The processing window narrows as dipentaerythritol mass fraction increases because the six primary hydroxyl groups raise the gel-point risk relative to a four-functional pentaerythritol at equivalent stoichiometry. In agitated production reactors, batch endpoint is controlled by a combination of acid value, melt viscosity, and agitator torque rather than by trial sampling alone. Acid value is commonly reduced to 8–12 mg KOH/g before letdown. Agitator amperage and torque signals are used to detect rapid viscosity increases that precede gelation. Residual alkali metal compounds in technical flake consume acid catalyst and increase batch-to-batch cook time; this is controlled by selecting grades with low residue on ignition and by adjusting catalyst charge based on the actual assay and ash content of the incoming lot.
Differences from pentaerythritol are also observed in final oligomer distribution. Partially esterified dipentaerythritol species have higher molecular weights and higher melt viscosities than corresponding pentaerythritol partial esters, which can reduce solvent tolerance and increase application viscosity. For this reason, dipentaerythritol is often used as a partial replacement in alkyd formulations rather than as a total replacement for pentaerythritol, particularly when a narrow acid-value endpoint and stable degree of polymerization are required. Published data for exact replacement ratios are formulation-dependent and are limited to specific fatty acid distributions and oil-length classes; no single substitution ratio applies across short-, medium-, and long-oil alkyds.
In UV-curable acrylate chemistry, dipentaerythritol is esterified with acrylic acid to produce dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate mixtures. The resulting multifunctional monomers create dense crosslinked networks and are evaluated for pendulum hardness by ASTM D4366 and for impact resistance by ASTM D2794. Neat monomer viscosity is formulation-dependent and is typically high enough to require heated handling at 50–60 °C or dilution with a difunctional reactive diluent. Formulators balance the high acrylate functionality against embrittlement; the central ether linkage provides some flexibility, but high degrees of conversion can produce film shrinkage and adhesion loss on steel substrates. In synthetic lubricant basestocks, polyol esters prepared from dipentaerythritol and C5–C10 carboxylic acids are characterized by lower volatility and higher oxidative stability compared with trimethylolpropane triesters, although pour point and viscosity may rise because of the higher molecular weight and ester group count. Oxidation performance is assessed by standard aviation lubricant oxidation and corrosion tests such as ASTM D4636 or by proprietary test sequences aligned with MIL-PRF-23699-class formulations.
In rosin ester tackifiers, substituting dipentaerythritol for pentaerythritol changes the average ester functionality and raises softening point. Rosin ester synthesis with dipentaerythritol is normally conducted under inert gas to an acid value below 20 mg KOH/g. Ring-and-ball softening point is measured according to ASTM E28, and Gardner color is measured according to ASTM D1544. The higher softening point is useful in hot-melt adhesive tackifiers, but the higher melt viscosity requires reactors with adequate torque capacity and may require a taller packed column or improved inert-gas sparging to remove water of esterification from the viscous melt. In ammonium polyphosphate-based intumescent coatings, dipentaerythritol functions as the carbonific component. The lower water solubility of dipentaerythritol relative to pentaerythritol is relevant for exterior-grade or humidity-aged intumescent films because water extraction can reduce char-forming efficiency. Char expansion is evaluated by cone calorimetry under ASTM E1354, but published data for specific dipentaerythritol-containing intumescent coating formulations are limited; the measured expansion ratio depends strongly on pigment volume concentration, ammonium polyphosphate grade, and film thickness. Incompatibility with amine-based additives is an operational limitation in some coating and esterification routes because basic amine species can neutralize acid catalysts or participate in unintended Michael addition with acrylated derivatives. Storage segregation from amine-containing hardeners and catalysts is therefore specified in material handling procedures.
Pre-drying is warranted when flake or powder has been stored at relative humidity above 60 %. Moisture uptake can produce caking in bulk silos and drift in the apparent hydroxyl value because aliquot mass is affected by water content. Silo discharge is maintained with desiccated air purges and mechanical vibration. Dipentaerythritol dust is combustible, and dust collection systems should be evaluated under NFPA 652 for combustible dust fundamentals. The material is not considered acutely hazardous under normal industrial handling, but the fine powder fraction can form explosive dust clouds in air if sufficient minimum ignition energy is present. Published data for particle-size distribution, triboelectric charging, and minimum ignition energy are grade-dependent; process safety assessments should use values obtained from the specific lot certificate or supplier technical data.
