Handing storage
Stable to air and moisture; incompatible with strong acids, bases, or oxidants (forms hydrogen upon decomposition); generally considered non-toxic, however thorough toxicity studies have not been performed; skin/eye contact and inhalation should be avoided.
Description
Poly(methylhydrosiloxane) is a reducing agent. For example, it can
be used for the reduction of esters to alcohols as well as the
reduction of aldehydes and ketone. It can also be used for the
reduction of phosphine oxides to phosphine. Recent study has also
used it for conjugate reduction of α, β-Unsaturated Carbonyl and
Carboxyl Compounds. Finally, it is also used in greener amine
synthesis mediated by reductive amination which is an alternative to
borohydrides.
Chemical Properties
Colorless liquid
Uses
Polymethylhydrosiloxane(PMHS) is an easily handled,inexpensive,non-toxic,and mild reducing agent. PMHS is attractive as a substitute for more expensive or hazardous silanes or siloxanes and as the stoichiometric reductant in catalytic organotin-mediated processes.
It can be cross linked by metal catalyst at low temperature to form waterproof membrane. It is used as waterproof agent of textile, glass, pottery, paper, leather, metal, cement and marble etc, especially in textile waterproof. It is used as insulator and cross linker of paper.
Poly(methylhydrosiloxane) is used in the reduction of esters to alcohols, catalyzed by a combination of titanocene dichloride and either n-BuLi or EtMgBr. It is a safer alternative to triethoxysilane, B22063, for reduction of phosphine oxides to phosphines, catalyzed by Ti(O-i-Pr)4. It is also used in greener amine synthesis by reductive amination as an alternative to borohydrides.
Preparation
Poly(methylhydrosiloxane) is prepared by hydrolysis of methyldichlorosilane followed by heating (60–150℃) the resultant mixture of cyclic
silanes in the presence of hexamethyldisiloxane generates the
linear polysiloxane.
Synthesis
Poly(methylhydrosiloxane)(PMHS) is synthesized by the controlled hydrolysis of MeSiHCl
2[1].
Advantages
PMHS is synthesized by the controlled hydrolysis of MeSiHCl2, a byproduct in producing Me2SiCl2, a feedstock for the silicone industry. As a byproduct of the silicone industry, it is a cheap, easy to handle, and environmentally friendly reducing agent. PMHS is more air and moisture-stable than other silanes and can be stored for long periods of time without loss of activity. In addition to being synthesized from a waste product, PMHS is cheap, stable to air and moisture, and is considered nontoxic[2].
References
[1] HEIN N M, SEO Y, LEE S J, et al. Harnessing the reactivity of poly(methylhydrosiloxane) for the reduction and cyclization of biomass to high-value products?[J]. Green Chemistry, 2019, 10: 2662-2669. DOI:10.1039/C9GC00705A.
[2] Hein, Nicholas M. et al. “Harnessing the reactivity of poly(methylhydrosiloxane) for the reduction and cyclization of biomass to high-value products?.” Green Chemistry 10 (2019): 2662–2669.
