CAS NO. 26798-98-1 N,N-Dimethylaminopentamethyldisilane

Frequently Asked Questions：

What is N,N-Dimethylaminopentamethyldisilane (CAS 26798-98-1)?

It is an amino-functional disilane with the linear formula (CH₃)₃Si–Si(CH₃)₂–N(CH₃)₂ (molecular formula C₇H₂₁NSi₂, MW 175.42). The molecule contains a Si–Si bond with one dimethylamino group on one silicon and five methyl groups in total — hence “pentamethyl”. It is a colorless to pale-yellow liquid, supplied at 95% min purity (GC), used as a silylating reagent, coupling agent and silicon-based material precursor.

What is the difference between 26798-98-1 and 26798-99-2?

They are different disilanes and easy to confuse. CAS 26798-98-1 is N,N-dimethylaminopentamethyldisilane — it has one dimethylamino group (Me₃Si–SiMe₂–NMe₂, C₇H₂₁NSi₂). CAS 26798-99-2 is 1,2-bis(dimethylamino)tetramethyldisilane — it has two dimethylamino groups, one on each silicon (Me₂N–SiMe₂–SiMe₂–NMe₂, C₈H₂₄N₂Si₂). Always order by CAS number and confirm the structure on the COA.

What is it used for?

Main applications: (1) a silylating / coupling reagent in organic and organosilicon synthesis; (2) a precursor or co-precursor for silicon-based thin films and materials in CVD/ALD development, thanks to its Si–Si backbone and amino leaving group; (3) a crosslinker / chain modifier for silicone polymers; and (4) an R&D building block for Si–Si bond chemistry and specialty disilanes.

Why is the Si–Si bond structure interesting?

Unlike ordinary aminosilanes built on a single silicon, this product carries a direct Si–Si bond. In deposition and polymer chemistry this provides a different reactivity profile — it can introduce Si–Si units into films or networks, supporting lower-temperature processing and tailored film composition. It is therefore valued both as a process reagent and as a development precursor for silicon-rich materials.

What purity do you supply?

Our standard grade is 95% min (by GC), suitable for R&D, pilot evaluation and industrial synthesis. Every batch ships with a Certificate of Analysis (COA). If your process requires a tighter specification — higher assay, controlled moisture or metal limits — tell us your target spec and we will quote a custom-produced batch accordingly.

What are the key physical properties?

Boiling point ~156 °C; density ~0.75 g/mL; refractive index nᴰ ~1.4431; flash point ~78 °C; vapor pressure around 4 mmHg at 25 °C. It is a free-flowing liquid at room temperature with an amine-like odor. Exact values are confirmed on each batch COA.

How should it be stored and handled?

It is highly moisture-sensitive (hydrolytic sensitivity grade 8): it reacts rapidly with water and protic solvents, liberating dimethylamine, and is classified corrosive (causes skin/eye burns). Keep tightly sealed in a cool, dry, dark place under dry inert conditions; handle in a fume hood with gloves and eye protection, away from water, acids and oxidizers. Full guidance is in the SDS.

What packaging options are available?

Standard packaging is fluoride bottles, fluorinated / iron / plastic drums or IBC tanks according to order quantity, sealed dry before dispatch. Small sealed sample bottles are available for evaluation, and special packaging (cylinders, ampoules, custom fittings) can be arranged on request.

Are COA and SDS provided? How is it shipped?

Yes. Each batch is supplied with COA and SDS. The product is classified as a flammable, corrosive dangerous good (UN 1993) and is shipped through certified dangerous-goods channels by sea, air or courier with complete documentation for smooth customs clearance.

Can I get a sample or a custom batch?

Absolutely. We support gram-scale samples for evaluation, custom-specification batches and scale-up to production volumes with stable lead times. Send us your target application, required purity and pack size, and we will reply with specification, price, lead time and sample availability — usually within one working day. Contact James Zhang at james.zhang@dakenchem.com.

Application Cases：

Case 1 — Silicon-Based Thin-Film Development (CVD/ALD Co-Precursor)

Used as a precursor or co-precursor in R&D of low-temperature silicon-containing films (SiNx, a-Si, SiCN). The Si–Si backbone supplies silicon while the dimethylamino leaving group supports clean vapor-phase reaction, making it a useful candidate for silicon-rich film process screening.

Case 2 — Silylating Reagent in Fine Chemical & Pharmaceutical Synthesis

Applied as a moisture-activated silylating reagent to protect or derivatize active-hydrogen groups (alcohols, amines, acids) in multi-step synthesis, where its disilane structure gives a distinct reactivity and by-product profile versus common trimethylsilyl reagents.

Case 3 — Coupling Agent for Inorganic–Organic Interfaces

Used to promote adhesion between inorganic fillers/metals/glass and organic resins in coatings, adhesives and sealants, improving interfacial bonding and moisture resistance of the final composite.

Case 4 — Silicone Polymer Crosslinker / Chain Modifier

Incorporated into silicone polymer formulations as a crosslinking or chain-modifying agent to adjust crosslink density, network structure and end properties such as hardness, thermal stability and chemical resistance.

Case 5 — Building Block for Specialty Disilanes & Electronic-Grade Organosilicon

Serves as a starting material for synthesizing other Si–Si bond compounds, functional disilanes and electronic-grade organosilicon intermediates for advanced materials research.