2 Neck Schlenk Reaction Flask QiMan Borosilicate Stopcock 24/40 Joint

Description

Product Overview

The 2 Neck Schlenk Reaction Flask from QiMan is engineered for demanding laboratory environments where precision, durability, and chemical resistance are essential. Constructed from high-temperature borosilicate glass, the flask tolerates rapid temperature changes and aggressive solvents without compromising structural integrity. Its two neck design provides independent access points for reagent addition, gas inlet, and sampling, while the integrated glass stopcock ensures a leak-tight seal during vacuum or inert-gas operations. The standard 24/40 joint on the stopcock matches common Schlenk line components, allowing seamless connection to condensers, traps, and other glassware. With a capacity ranging from 50 ml to 500 ml, the flask accommodates a variety of reaction scales, and the clear glass body enables easy visual monitoring of reaction progress.
Designed with laboratory safety in mind, the flask’s thick wall construction reduces the risk of breakage under mechanical stress, while the smooth, polished finish prevents accidental scratching that could harbor contaminants. The dimensions of 2.89 × 2.89 × 4.8 inches provide a compact footprint that fits comfortably on standard bench space and within most heating mantles or oil baths. QiMan’s commitment to quality control is reflected in the rigorous testing each unit undergoes, including pressure resistance, thermal shock, and dimensional accuracy checks. The product is supplied with a reusable glass stopcock that can be easily cleaned with standard laboratory solvents, extending the flask’s service life and offering cost-effective sustainability for research facilities.
The flask’s dimensions of 2.89 × 2.89 × 4.8 inches translate to a convenient volume-to-surface ratio, allowing efficient heat transfer when placed in a heating mantle or oil bath. The thin yet robust wall thickness of approximately 2 mm provides sufficient strength while keeping the overall weight manageable for easy handling. The glass stopcock is equipped with a precision-machined valve that offers smooth rotation and precise control of gas flow, reducing the risk of sudden pressure changes. All joints are ground to a fine finish to ensure a snug fit with standard ground-glass adapters, minimizing the need for additional sealing compounds. The product complies with ASTM E‑258 standards for borosilicate glass, guaranteeing consistent quality across production batches.

Usage

The 2 Neck Schlenk Reaction Flask is ideally suited for organic synthesis procedures that require an inert atmosphere, such as Grignard reactions, metal-catalyzed couplings, and moisture-sensitive polymerizations. Its dual-neck configuration allows one neck to be connected to a vacuum line while the second serves as a reagent inlet or sampling port, enabling simultaneous evacuation and addition of chemicals without exposing the reaction mixture to ambient air. Researchers can attach a condenser to the stopcock joint for reflux operations, or connect a drying tube to maintain a dry nitrogen flow throughout the experiment.
In addition to synthetic chemistry, the flask performs well in analytical applications such as distillation, solvent recovery, and gas-phase sampling where a tight seal and precise temperature control are critical. The clear glass walls allow operators to monitor color changes, precipitate formation, or gas evolution in real time, reducing the need for invasive sampling. Because the flask is reusable and compatible with standard laboratory cleaning protocols, it supports sustainable laboratory practices and minimizes waste compared with disposable plastic alternatives.
To achieve optimal results, users should pre-condition the flask by heating it gradually to the desired reaction temperature, avoiding thermal shock that could cause micro-cracks. When performing vacuum distillation, connect the stopcock to a cold trap to capture volatile by-products, and monitor the pressure gauge closely to maintain safe operating limits. For inert-gas reactions, purge the system with dry nitrogen or argon before introducing reagents, and keep the stopcock closed when the flask is not actively being vented. Regular inspection of the glass surface for scratches or etching will help maintain the integrity of the seal and prevent contamination of sensitive reactions.

Why Choose Us

QiMan is a recognized supplier of high-quality laboratory glassware, and each Schlenk flask is manufactured under strict ISO-9001 quality management standards. The company sources premium borosilicate raw material that meets ASTM C-743 specifications, ensuring the final product can withstand temperatures up to 500 °C and resist chemical attack from acids, bases, and organic solvents. Each flask undergoes a multi-stage inspection process that includes visual inspection for cracks, dimensional verification, and pressure testing to certify leak-free performance.
Customers benefit from QiMan’s responsive technical support team, which can assist with installation, troubleshooting, and best-practice recommendations for Schlenk line setups. In the unlikely event of damage during shipping, the company offers a hassle-free replacement policy, ensuring that research timelines are not disrupted. By choosing this flask, laboratories gain a reliable, reusable tool that contributes to consistent experimental results and long-term cost savings.
Beyond product performance, QiMan emphasizes environmental responsibility by implementing a closed-loop recycling program for end-of-life glassware. Customers can return used flasks for safe disposal or refurbishment, reducing landfill waste and conserving raw materials. The company also adheres to REACH and RoHS regulations, ensuring that the glass contains no hazardous substances that could leach into reactions. By integrating these sustainability practices, QiMan helps laboratories meet their green-lab initiatives while maintaining high scientific standards.

Key Features

• High-temperature borosilicate glass resists thermal shock and aggressive chemicals, extending the flask’s lifespan for repeated use in demanding experiments.
• Dual-neck design provides separate ports for reagent addition and vacuum connection, enabling simultaneous manipulation without breaking the inert atmosphere.
• Integrated glass stopcock with a standard 24/40 joint ensures leak-tight sealing and easy attachment to condensers, traps, and other Schlenk line components.
• Clear glass body allows real-time visual monitoring of reaction progress, color changes, and gas evolution, reducing the need for invasive sampling.
• QiMan provides dedicated after-sales support and a replacement guarantee, ensuring customer confidence and uninterrupted laboratory workflow.

FAQ

Can the flask be used for high-pressure reactions?

Yes, the 2 Neck Schlenk Reaction Flask can safely handle moderate pressure conditions typical of Schlenk line operations, such as vacuum drawdown and gentle nitrogen back-pressure. The borosilicate glass is rated for pressures up to 0.5 bar above atmospheric, and the glass stopcock’s 24/40 joint is designed to maintain a tight seal under these conditions. For high-pressure applications exceeding this rating, a specialized pressure-rated flask should be selected. Always inspect the flask for cracks before use, and never exceed the manufacturer’s recommended temperature and pressure limits to avoid glass failure.

How do I clean and maintain the stopcock?

The glass stopcock should be cleaned after each use to prevent residue buildup that could affect sealing performance. Disassemble the stopcock by gently unscrewing it from the flask neck, then soak the components in a suitable solvent such as acetone or ethanol for 10-15 minutes. Use a soft brush or pipe cleaner to remove any remaining material from the internal channels. Rinse thoroughly with distilled water and allow the parts to air-dry completely before reassembly. For stubborn deposits, a brief soak in a dilute acid solution (e.g., 5 % nitric acid) followed by thorough rinsing is effective. Regular maintenance ensures a reliable vacuum seal and prolongs the flask’s service life.

What sizes are available and how to choose the right one?

The 2 Neck Schlenk Reaction Flask is offered in several capacities, including 50 ml, 100 ml, 250 ml, and 500 ml, each with compatible 24/40 joint stopcocks. Selecting the appropriate size depends on the scale of the reaction, the volume of reagents, and the space available on the laboratory bench or heating mantle. For small-scale screening or moisture-sensitive experiments, a 50 ml or 100 ml flask provides sufficient volume while minimizing headspace. Larger synthetic batches benefit from the 250 ml or 500 ml models, which reduce the number of transfers and improve temperature uniformity. Consider the required reaction time, heat distribution, and the size of ancillary equipment when deciding on the flask size.

What is the recommended storage condition for the flask?

The flask should be stored in a clean, dry environment away from direct sunlight and extreme temperature fluctuations. Ideally, keep the glassware in a dedicated cabinet with low humidity to prevent moisture absorption, which can lead to surface etching over time. Place the flask upright or on a padded rack to avoid contact with hard surfaces that could cause scratches. If the flask will not be used for an extended period, consider sealing the stopcock with a protective cap and covering the opening with a lint-free cloth to keep dust out. Regularly inspect stored flasks for any signs of damage before re-introducing them into active experiments.

How does the flask compare to plastic reaction vessels?

Compared with disposable plastic reaction vessels, the borosilicate Schlenk flask offers superior chemical resistance, higher temperature tolerance, and a longer service life. Plastic containers can deform or leach contaminants when exposed to strong acids, bases, or solvents, potentially compromising reaction purity. The glass flask’s transparent walls provide clear visual access, whereas many plastics become opaque under certain conditions. Additionally, the reusable nature of the glass flask reduces waste and lowers long-term costs, especially in high-throughput laboratories. While plastic vessels are convenient for single-use applications, the QiMan Schlenk flask delivers more reliable performance for rigorous, repeatable experiments that demand precise control of atmosphere and temperature.