| HS Code | 654278 |
| Product Name | Lab Grade Toluene |
| Chemical Formula | C7H8 |
| Cas Number | 108-88-3 |
| Molecular Weight | 92.14 g/mol |
| Appearance | Colorless liquid |
| Odor | Aromatic, benzene-like |
| Grade | Laboratory grade |
| Purity | ≥99.5% (typical) |
| Density | 0.8669 g/mL at 20 °C |
| Boiling Point | 110.6 °C |
| Melting Point | -95 °C |
| Flash Point | 4 °C (closed cup) |
| Solubility | Slightly soluble in water; miscible with most organic solvents |
| Vapor Pressure | 28.4 mmHg at 20 °C |
| Refractive Index | 1.4961 at 20 °C |
| Storage Conditions | Store in a cool, dry, well-ventilated area away from ignition sources |
| Hazard Class | Flammable liquid, Category 2 |
| Un Number | 1294 |
As an accredited Lab Grade Toluene factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Lab Grade Toluene, 1 L amber glass bottle with PTFE-lined cap, hazard labels, secure vented carton, for laboratory use only. |
| Container Loading (20′ FCL) | Loading of lab-grade toluene into a 20′ FCL container, with properly secured, labelled hazardous chemical packaging for safe transport. |
| Shipping | Lab Grade Toluene is shipped as a hazardous flammable liquid, UN1294, Class 3, Packing Group II. It requires UN-rated packaging, flammable liquid labels, proper shipping papers, and emergency response information. Transport must comply with DOT, IATA, or IMDG rules, keeping it away from ignition sources and oxidizing agents. |
| Storage | Store Lab Grade Toluene in a cool, dry, well-ventilated area away from heat, sparks, open flames, and sunlight. Keep containers tightly closed, properly labeled, and grounded in an approved flammable-liquid cabinet. Use secondary containment, separate from strong oxidizers and acids, and follow local fire-safety regulations. Store only in original or approved containers. Ensure adequate ventilation and eliminate ignition sources. |
| Shelf Life | Lab Grade Toluene has an indefinite shelf life if stored tightly closed, cool, dry, away from ignition sources and light. |
Lab-grade toluene with a water specification of ≤0.03 wt% and residue after evaporation of ≤10 ppm is charged at 5.0–8.0 L/kg of limiting reactant in glass-lined condensation reactors where azeotropic removal of water drives esterification, amidation, or imine formation to completion. The toluene–water heterogeneous azeotrope distills at 84–85 °C and carries approximately 19–20 wt% water in the overhead vapour; bulk liquid temperature is held at 110–112 °C under total reflux while condensate separates in a Dean-Stark trap. Compliance follows ICH Q3C Option 1 for Class 2 residual solvents, with a permitted daily exposure of 8.9 mg/day and a concentration limit of 890 ppm in the drug substance, verified by headspace gas chromatography under USP <467> and Ph. Eur. 5.4. Downstream processing proceeds by inerting the reactor to an oxygen concentration below 5 vol% to avoid flammable atmospheres, heating to reflux for 8–16 h, collecting water until distillate no longer separates, and then stripping bulk toluene at 150–200 mbar; crystallization from an antisolvent followed by vacuum drying reduces residual toluene below the pharmacopeial limit. Terminal product types include amide and ester active pharmaceutical intermediates, carboxamide coupling products, and imine intermediates intended for salt formation. Operational boundary: water in fresh toluene exceeding 0.05 wt% reduces azeotropic efficiency and increases cycle time, so lab-grade material is held in closed stainless steel or glass containers under nitrogen.
In residual solvent method validation, lab-grade toluene is prepared as a primary stock solution at 1000–5000 mg/L in methanol, then serially diluted to calibration levels of 0.5 mg/L, 1.0 mg/L, 5.0 mg/L, 10 mg/L, 25 mg/L, 50 mg/L, and 100 mg/L; for headspace applications the working range typically spans 0.1–20 mg/L per vial. Method verification is governed by ISO/IEC 17025:2017 clause 7.2.1.5, reference material production by ISO 17034:2016, and volatile organic measurement by EPA Method 8260D with purge-and-trap or headspace introduction. Downstream analytical processing uses Class A volumetric glassware, a balance with readability of 0.01 mg, amber borosilicate headspace vials with PTFE-silicone septa, and a GC–MS system fitted with a DB-624 column of 30 m × 0.25 mm × 1.4 µm; vials are equilibrated at 80 °C for 30 min and injected at a split ratio of 20:1. The terminal output from this segment includes certified reference solutions, spiking standards for pharmaceutical and environmental laboratories, and retention-time qualification mixes. A threshold boundary arises from evaporative loss during serial dilution: toluene vapour pressure at 20 °C is 2.9 kPa, so dilutions are capped immediately and stored at 4 °C to keep nominal concentration drift below ±5% between preparation and use.
Formulations based on polychloroprene elastomer use lab-grade toluene as the primary aromatic component of a solvent blend in which total solids are maintained at 18–22 wt% and the solvent fraction contains 50–65 wt% toluene, with methyl ethyl ketone and n-hexane completing the blend. The solvent grade must meet low water and acid specifications because free moisture reacts with zinc oxide and magnesium oxide accelerators, shifting gel formation and reducing bond strength. Downstream mixing is performed in cooled stainless steel vessels at a batch temperature no higher than 35 °C, with polychloroprene first milled or cut, then dispersed in the solvent blend, followed by addition of tackifying resin, zinc oxide, and magnesium oxide; viscosity is adjusted to 1800–3500 mPa·s at 20 °C using a Brookfield viscometer with spindle 4 at 20 rpm. Terminal products include contact adhesives for footwear lasting, furniture edge banding, and construction panel lamination. Compliance under EU REACH Annex XVII Entry 48 restricts placing toluene as a substance or mixture on the market for the general public at concentrations equal to or above 0.1 wt%, so industrial and professional formulations require restricted distribution and documented worker exposure controls. The same formulations are classified under GHS H225, H304, H315, H336, H361d, and H373, making closed-loop solvent transfer and local exhaust ventilation mandatory.
Blending of lab-grade toluene into primary reference fuel formulations for spark-ignition engine knock testing is performed under ASTM D2699-22 and ASTM D2700-22, with ISO 5164:2014 used as the corresponding international method for research octane number. Toluene is incorporated at 10–25 vol% together with iso-octane and n-heptane to shift octane sensitivity and reproduce the knock behaviour of aromatic-containing commercial gasolines; its reported research octane number is approximately 120, but density correction at 20 °C is required because volumetric blending of aromatic and paraffinic components is non-ideal. Downstream preparation involves gravimetric weighing on a balance accurate to 0.01 g, closed-loop vapour recovery during transfer due to flash point 4 °C, and homogenization at 20.0 °C before introduction into a calibrated CFR F-1 or F-2 knock-test engine operating under standardized intake air temperature, coolant temperature, and compression ratio settings. Terminal product types are certified reference fuels, octane calibration blends for refinery and regulatory laboratories, and engine development quality-control fluids. Operational boundary: water content above 50 ppm in the finished reference blend can produce phase separation in ethanol-containing test fuels and is therefore controlled by using dried toluene and storing finished blends in sealed stainless steel containers under a nitrogen blanket.
In the deposition of donor–acceptor active layers for organic photovoltaic test devices and organic thin-film transistors, lab-grade toluene is used at total solute loadings of 10–30 mg/mL with donor:acceptor mass ratios of 1:1.0 to 1:1.5; the solvent is selected because its boiling point of 110.6 °C permits heated dissolution without entering the thermal degradation window of many non-fullerene acceptors. Dissolution is conducted at 60–70 °C for 8–12 h in a nitrogen-purged glovebox with oxygen and moisture maintained below 1 ppm, followed by filtration through a 0.22–0.45 µm PTFE syringe filter and spin coating onto ITO/PEDOT:PSS substrates at 1000–3000 rpm; annealing at 100–120 °C for 10–20 min removes residual solvent and controls phase separation. Cleanroom compliance follows ISO 14644-1:2015 Class 5, and outgassing for device packages is evaluated under ASTM E595-15 when required. Terminal outputs include organic photovoltaic cells, photodetector test structures, and organic thin-film transistor channels used for mobility screening. Published data for film thickness reproducibility across different donor polymer batches is limited, but batch-to-batch molecular-weight variation can shift dried film thickness by several nanometres under identical spin conditions, so viscosity of the coating solution is checked before each campaign.
Determination of viscosity number and intrinsic viscosity for polystyrene and certain styrene copolymers is carried out with lab-grade toluene at polymer concentrations of 0.1–0.5 g/dL, prepared by dissolution at 25.0 °C under gentle agitation and filtered through sintered glass to remove microgel. The measurement procedure follows ISO 1628-1:2021 and ASTM D2857-16, using a suspended-level Ubbelohde viscometer thermostatted at 25.00 ± 0.01 °C; efflux times are recorded until consecutive readings agree within ±0.2%, and the data are reduced through Huggins and Kraemer plots to obtain intrinsic viscosity. Toluene with residue after evaporation above 10 ppm or water above 0.03 wt% is rejected because non-volatile residue deposits in the capillary and changes the kinetic energy correction, while water interacts with polar comonomers and produces turbid solutions. Downstream products include viscosity number certificates, polymer characterisation data packages for reactor grade transfers, and reference data used to support Mark–Houwink parameter calculations in product development. The operational boundary relevant to this method is polymer concentration: below 0.05 g/dL, wall adsorption can bias efflux time, whereas above 1.0 g/dL chain entanglement makes relative viscosity exceed the linear range of the Huggins equation.
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Lab Grade Toluene is supplied under product designation TOL-LAB-4L as a clear, colorless aromatic hydrocarbon with CAS registry number 108-88-3 and molecular formula C7H8. The material is packaged in 4 L high-density polyethylene containers with PTFE-lined closures and is controlled for assay, water content, evaporation residue, and titrable acid/base rather than for the full low-particulate and low-UV-absorbance profile required of HPLC-grade solvents. This distinction places the product between technical-grade toluene and ACS reagent-grade toluene: it is suitable for synthesis, liquid–liquid extraction, glassware rinsing, and polymer dissolution, but it is not automatically a drop-in replacement for spectrophotometric or gradient-grade mobile phases. Routine physical constants include a boiling point of 110.6 °C, density of 0.865 g/mL at 20 °C, flash point of 4.4 °C closed cup, and refractive index n20/D of 1.4960–1.4980. The molecular weight is 92.14 g/mol, identifying the solvent as the monocyclic aromatic hydrocarbon toluene rather than a mixed xylene or aromatic stream.
ACS reagent toluene is formalized by the ACS Reagent Chemicals monograph, which sets assay at ≥99.5% and restricts water to ≤0.03% and residue after evaporation to ≤0.001%. HPLC-grade toluene is additionally controlled for UV transmittance, particulate matter, and water to suit low-wavelength detection; published data for this specific configuration is limited, but typical certificates report water ≤0.02% and evaporation residue ≤0.0005%. Lab grade material may meet assay and residue specifications but is not necessarily filtered through 0.2 µm membranes or validated for absorbance at 286 nm. Technical-grade toluene contains variable benzene, xylene, and sulfur-bearing impurities and should not be used for trace-sensitive work.
| Parameter | Lab Grade | ACS Reagent | HPLC | Technical |
|---|---|---|---|---|
| Assay by GC | ≥ 99.0–99.5% | ≥ 99.5% | ≥ 99.8% | 90–99% |
| Water | ≤ 0.05% | ≤ 0.03% | ≤ 0.02% | not controlled |
| Residue after evaporation | ≤ 0.002% | ≤ 0.001% | ≤ 0.0005% | variable |
| UV suitability | not specified | not specified | controlled absorbance at 285–400 nm | not specified |
| Acidity/alkalinity | ≤ 0.0006 meq/g | ≤ 0.0005 meq/g | ≤ 0.0003 meq/g | not controlled |
| Sulfur compounds | low, lot-specific | passes ACS test | low | not controlled |
The product is filled into 4 L high-density polyethylene bottles with PTFE-lined closures and an outer cardboard overpack. A typical batch retains the release limits shown in Table 2. Density at 20 °C is 0.865–0.867 g/mL by ASTM D4052, color is ≤10 Pt-Co by ASTM D5386, and residue after evaporation is ≤0.002% by ASTM D1353. Water content is controlled to ≤0.05% through a Karl Fischer method aligned with ASTM E1064; this water limit is the principal operational difference from an ACS-grade lot, where water is typically ≤0.03%. Gas chromatographic assay by ASTM D2360 is normalized to ≥99.5% for the sum of toluene and trace aromatic isomers. Acidity and alkalinity by ASTM D847 are controlled to ≤0.0006 meq/g. Benzene content is lot-specific and should be requested when the final application imposes a limit lower than the technical-grade default; the product is not certified as benzene-free.
| Parameter | Limit | Reference method |
|---|---|---|
| Assay, normalized GC | ≥ 99.5% | ASTM D2360 |
| Water | ≤ 0.05% | ASTM E1064 |
| Residue after evaporation | ≤ 0.002% | ASTM D1353 |
| Color, Pt-Co | ≤ 10 | ASTM D5386 |
| Density at 20 °C | 0.865–0.867 g/mL | ASTM D4052 |
| Acidity/alkalinity | ≤ 0.0006 meq/g | ASTM D847 |
Toluene exhibits a vapor pressure of 28.4 mmHg at 25 °C and dynamic viscosity of approximately 0.56 mPa·s. The Hildebrand solubility parameter of toluene is 18.2 MPa0.5, which is close to that of polystyrene, so dissolution proceeds by swelling rather than simple surface erosion. Rotary evaporation under a 40 °C water bath requires vacuum below 80 mbar because the vapor pressure at that temperature is approximately 79 mbar. A 0.45 µm PTFE membrane filtration is recommended before using the solvent in light-scattering or intrinsic-viscosity work.
Storage of toluene requires a flammable-liquids cabinet compliant with NFPA 30 and local fire code. The closed-cup flash point is 4.4 °C, and the autoignition temperature is 480 °C. The flammable range is 1.1%–7.1% by volume in air. Vapor is heavier than air; vapor density is 3.14 relative to air, and an 8-hour exposure limit of 20 ppm as an ACGIH TLV-TWA applies. OSHA PEL is 200 ppm TWA with a 300 ppm ceiling. Containers should be bonded and grounded before transfer; flow velocities in 25 mm internal-diameter stainless-steel or PTFE lines should remain below 1.5 m/s as recommended by NFPA 77. Toluene permeates natural rubber and neoprene; for immersion cleaning, use butyl rubber or polyvinyl alcohol gloves with manufacturer-specific breakthrough data. Avoid contact with strong oxidizers, concentrated nitric acid, and sulfur trioxide, which can initiate rapid exothermic reactions. Under the Globally Harmonized System, toluene is classified as H225, H304, H315, H336, H361d, and H373.
For moisture-sensitive polymerization and organometallic chemistry, water in the product at the 0.05% limit corresponds to 500 mg/kg. Drying over activated 3A molecular sieves for 24 h can reduce water to 10–20 mg/kg, but should not be applied to ketone-containing streams because the sieves can promote aldol-type condensation reactions. The toluene–water heteroazeotrope boils at 84.1 °C; in a Dean-Stark apparatus the water separates as the denser lower phase, while the toluene-rich upper phase returns to the reaction vessel. Titrable acid/alkalinity at ≤0.0006 meq/g prevents uncontrolled neutralization in acid-sensitive esterifications, but dissolved oxygen is not removed by the dry solvent. For air-sensitive phosphine ligands or butyllithium-mediated deprotonations, sparge with argon through a fritted glass sparger for 20–30 min before reagent addition. If used in anionic styrene polymerization, lot water must be verified by Karl Fischer titration before catalyst addition, because water in the solvent can quench initiator.
Liquid–liquid extraction of nonpolar analytes from water can be performed in a 2 L PTFE-stopcock separatory funnel with a solvent-to-sample ratio of 1:1; phase separation after gentle venting usually requires 2–5 min. Toluene dissolves approximately 0.52 g/L in water at 25 °C, and the upper organic phase can retain dissolved water that should be removed with anhydrous sodium sulfate before concentration. The octanol–water partition coefficient is log P 2.73, which is sufficient for extraction of many neutral aromatics, fatty acid esters, and nonpolar polymers. Concentration by rotary evaporation is conducted at a 40 °C water bath and vacuum below 80 mbar; at this temperature the vapor pressure of toluene is approximately 79 mbar. Compared with dichloromethane, toluene's lower vapor pressure at ambient conditions extends evaporation time and improves recovery of semi-volatile compounds, but it also requires more time to remove residual solvent at the end of a method. For HPLC with UV detection at 254 nm, lab grade toluene is inappropriate because the aromatic absorbance cut-off of toluene is approximately 286 nm.
For glassware that previously contained high-molecular-weight grease or polymer residues, rinses with lab grade toluene followed by a volatile wetting solvent remove residual films; glassware should then be dried at 150 °C for 2 h if the next use is trace-level and the toluene residue limit is below the method detection limit.
For polymer dissolution, polystyrene and many hydrocarbon resins dissolve under low-shear agitation at 25 °C to form 5–10 wt% solutions for viscosity or film-casting experiments. Intrinsic viscosity measurements according to ISO 1628-1:2021 should use filtered solvent with evaporation residue checked, because a 0.002% residue can introduce insoluble particulates in film casting. Lab grade toluene should not be used as a mobile phase in HPLC with UV detection below 286 nm; gradient-grade or spectrophotometric-grade material is required for that application. It is also not certified for headspace gas chromatography of residual solvents in pharmaceutical matrices, where ICH Q3C limits may require solvents with lot-specific benzene and toluene impurity data. Under ICH Q3C, toluene is a Class 2 residual solvent with a permitted daily exposure of 8.9 mg/day and a concentration limit of 890 ppm; lab grade toluene is not automatically suitable for final pharmaceutical residual-solvent testing without verification.
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