Diethoxymethylvinylsilane: Properties, Handling & Lab Use Guide

Diethoxymethylvinylsilane is a bifunctional organosilane reagent that combines a reactive vinyl group with hydrolyzable ethoxy substituents, making it a versatile building block for surface functionalization, polymer crosslinking, and organosilicon synthesis.

Chemical Name

Diethoxymethylvinylsilane

CAS Number

5507-44-8

Molecular Formula

C7H16O2Si

Molecular Weight

160.28 g/mol

Key Functional Groups

Vinyl (Si–CH=CH₂) and two ethoxy (Si–OEt) groups with one methyl substituent

Aladdin SKU

D767299

Chemical Identity and Key Properties

Diethoxymethylvinylsilane (CAS 5507-44-8, MW 160.28 g/mol, molecular formula C₇H₁₆O₂Si) is a trifunctionally substituted silane bearing one vinyl group, one methyl group, and two ethoxy groups on the silicon center. The vinyl group (Si–CH=CH₂) is polymerizable and can participate in radical, hydrosilylation, or metathesis reactions, while the ethoxy groups (Si–OEt) undergo hydrolysis in the presence of moisture to form silanol intermediates (Si–OH), which subsequently condense to form siloxane (Si–O–Si) networks.

As a liquid at room temperature, diethoxymethylvinylsilane is miscible with common organic solvents such as ethanol, toluene, and diethyl ether. It is moisture-sensitive and should be handled under anhydrous conditions to prevent premature hydrolysis and self-condensation. Its vapor is flammable; therefore appropriate precautions must be observed during use.

Laboratory Applications

Surface Functionalization: The hydrolyzable ethoxy groups allow diethoxymethylvinylsilane to bond covalently to hydroxyl-rich surfaces such as silica, glass, alumina, and metal oxides. After hydrolysis and condensation, a thin siloxane film bearing pendant vinyl groups is formed, enabling subsequent grafting of polymers or other functional molecules via radical or thiol-ene chemistry.

Polymer Crosslinking: When incorporated into polyolefin or silicone formulations, the vinyl functionality participates in peroxide- or radiation-initiated crosslinking, improving thermal stability, mechanical strength, and solvent resistance of the resulting material.

Organosilicon Synthesis: Diethoxymethylvinylsilane serves as a versatile monomer or intermediate in the preparation of functional polysiloxanes, silsesquioxane networks, and hybrid organic-inorganic materials. The methyl group provides hydrophobicity and controls the degree of crosslinking relative to fully hydrolyzable triethoxyvinylsilane analogues.

Hydrosilylation Reactions: The terminal vinyl group is an excellent substrate for platinum- or rhodium-catalyzed hydrosilylation, allowing introduction of the diethoxymethylsilyl moiety onto Si–H-functionalized substrates or oligomers.

Safe Handling, Storage, and Disposal

Personal Protective Equipment (PPE): Always wear chemical-resistant gloves (e.g., nitrile), safety goggles, and a laboratory coat when handling diethoxymethylvinylsilane. Work in a well-ventilated fume hood to minimize inhalation of vapors.

Moisture Control: Store under an inert atmosphere (nitrogen or argon) with desiccant. Use anhydrous syringes or cannula transfers; reseal containers promptly after each use. Exposure to atmospheric moisture triggers hydrolysis and gelation, reducing reagent quality.

Flammability Precautions: Keep away from open flames, sparks, and hot surfaces. Ground and bond containers when transferring bulk quantities. The vapor-air mixture can be ignited; ensure adequate ventilation and use explosion-proof equipment where required.

Storage Conditions: Store in a cool, dry, well-ventilated area away from oxidizers, strong acids, and bases. Typical recommended storage temperature is 2–8 °C or as specified on the product label. Keep tightly sealed.

Disposal: Dispose of waste material in accordance with local, regional, and national regulations for flammable organosilane solvents. Do not pour down the drain. Consult your institution's Environmental Health and Safety (EHS) office for approved disposal procedures.

Quality, Purity, and Analytical Verification

Research-grade diethoxymethylvinylsilane should be characterized before use to confirm identity and purity. Recommended analytical techniques include:

• ¹H and ¹³C NMR Spectroscopy: Confirms the presence and integrity of the vinyl (δ ~6.0–6.4 ppm, CH=CH₂; δ ~5.8 ppm, =CH₂), methyl (Si–CH₃), and ethoxy (–OCH₂CH₃) proton environments.
• ²⁹Si NMR Spectroscopy: Provides direct evidence of the silicon chemical environment and can detect hydrolysis or condensation products.
• Gas Chromatography (GC): Quantifies purity and detects volatile impurities or hydrolysis byproducts (e.g., ethanol).
• Karl Fischer Titration: Verifies that water content is sufficiently low (typically <100 ppm) to ensure reagent stability during storage.

Aladdin Scientific provides a Certificate of Analysis (CoA) with each lot; always verify the CoA purity specification and lot number against your requirements before use.

Regulatory and Safety Classification Overview

Diethoxymethylvinylsilane is classified as a flammable liquid under standard chemical hazard frameworks (e.g., GHS). Key hazard categories typically associated with this compound include flammable liquid, skin and eye irritant, and respiratory irritant upon prolonged vapor exposure. Users should consult the current Safety Data Sheet (SDS) supplied by Aladdin Scientific (SKU D767299) for authoritative GHS classification, signal words, hazard and precautionary statements, first-aid measures, and transport information.

For international shipping, this compound may be classified under IATA/IMDG as a flammable liquid (UN class 3). Always confirm current transport classification with your logistics provider and comply with all applicable regulations before shipment.

Note: Regulatory classifications are subject to change; always consult the most current SDS and applicable national regulations.

Frequently asked questions

What is diethoxymethylvinylsilane used for in the laboratory?

Diethoxymethylvinylsilane is used primarily as a silane coupling agent for surface functionalization of glass and oxide surfaces, as a crosslinking comonomer in polyolefin and silicone systems, and as a monomer or intermediate in the synthesis of functional polysiloxanes and hybrid organic-inorganic materials. Its dual reactivity — the hydrolyzable ethoxy groups and the polymerizable vinyl group — makes it versatile across polymer chemistry and materials science applications.

How should diethoxymethylvinylsilane be stored to maintain its quality?

Diethoxymethylvinylsilane should be stored in a tightly sealed container under an inert atmosphere (nitrogen or argon) with a desiccant, in a cool, dry, well-ventilated location away from moisture, heat sources, oxidizers, and ignition sources. A storage temperature of 2–8 °C is typically recommended; consult the product label and SDS for lot-specific guidance. Containers should be resealed immediately after each use to prevent moisture ingress and premature hydrolysis.

Is diethoxymethylvinylsilane the same as vinyltriethoxysilane?

No, they are distinct compounds. Diethoxymethylvinylsilane has two ethoxy groups and one methyl group on silicon (in addition to the vinyl group), whereas vinyltriethoxysilane (VTES) has three ethoxy groups and no methyl group. This difference means diethoxymethylvinylsilane has a lower degree of hydrolyzability and introduces one non-reactive methyl substituent, resulting in a less densely crosslinked siloxane network compared to VTES. The choice between them depends on the desired crosslink density and surface hydrophobicity in your specific application.

What precautions are needed when handling diethoxymethylvinylsilane?

Users should wear nitrile gloves, safety goggles, and a lab coat, and work exclusively in a well-ventilated fume hood. Because the compound is flammable, all ignition sources must be eliminated from the work area. Transfers should be performed with anhydrous syringes or cannulae to avoid moisture contamination. In case of skin or eye contact, flush immediately with copious water and seek medical attention. Refer to the current SDS for complete first-aid and emergency procedures.

References

1. Arkles, B. Silane Coupling Agents: Connecting Across Boundaries. Gelest, Inc., 2014. General reference on organosilane chemistry and applications.
2. Plueddemann, E. P. Silane Coupling Agents, 2nd ed.; Plenum Press: New York, 1991. Classic textbook on the chemistry and use of silane coupling agents.
3. Brook, M. A. Silicon in Organic, Organometallic, and Polymer Chemistry; Wiley-Interscience: New York, 2000. Comprehensive reference for organosilane and polysiloxane chemistry.

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