Silylation of Alcohols and Phenols with Hexamethyldisilazane over Highly Reusable Propyl Sulfonic Acid Functionalized Nanostructured SBA-15

Synthesis of some silyl derivatives of graphene oxide

In this work, we synthesized some organosilicon derivatives of graphene oxide (GO) containing various groups such as trimethyl, triethyl, dimethyl-tert-Bu, and dimethyl-vinyl. Also, some reactions were done in the presence of DES, as catalyst. This green catalyst improved the yields of reactions successfully. Synthesis of methoxy, and ethoxy vinyl silyl ethers of GO were done. In this work, hybrid organic-inorganic was done. In the next step, network polymers of GO with styrene, and methacrylic acid (MAA) were done. Incorporation of organosilicon groups were modified GO properties for example thermal stability or it.

Hydrosilane σ-Adduct Intermediates in an Adaptive Zinc-Catalyzed Cross-dehydrocoupling of Si-H and O-H Bonds

Three-coordinate Ph BOXMe 2 ZnR (Ph BOXMe 2 =phenyl-(4,4-dimethyl-oxazolinato; R=Me: 2 a, Et: 2 b) catalyzes the dehydrocoupling of primary or secondary silanes and alcohols to give silyl ethers and hydrogen, with high turnover numbers (TON; up to 107 ) under solvent-free conditions. Primary and secondary silanes react with small, medium, and large alcohols to give various degrees of substitution, from mono- to tri-alkoxylation, whereas tri-substituted silanes do not react with MeOH under these conditions. The effect of coordinative unsaturation on the behavior of the Zn catalyst is revealed through a dramatic variation of both rate law and experimental rate constants, which depend on the concentrations of both the alcohol and hydrosilane reactants. That is, the catalyst adapts its mechanism to access the most facile and efficient conversion. In particular, either alcohol or hydrosilane binds to the open coordination site on the Ph BOXMe 2 ZnOR catalyst to form a Ph BOXMe 2 ZnOR(HOR) complex under one set of conditions or an unprecedented σ-adduct Ph BOXMe 2 ZnOR(H-SiR'3 ) under other conditions. Saturation kinetics provide evidence for the latter species, in support of the hypothesis that σ-bond metathesis reactions involving four-centered electrocyclic 2σ-2σ transition states are preceded by σ-adducts.

Propylsulfonic and arenesulfonic functionalized SBA-15 silica as an efficient and reusable catalyst for the acidolysis of soybean oil with medium-chain fatty acids

The objective of this work was to develop a feasible ecofriendly process to produce medium-chain fatty acid (MCFA)-enriched structured lipids (SLs) in heterogeneous manners. For this purpose, the propyl-SO3H or arene-SO3H-modified SBA-15 materials were prepared through a surface functionalization of SBA-15 silica with propyl-SO3H and arene-SO3H groups. The organosulfonic acid-functionalized SBA-15 materials were characterized by Brönsted acidity determination, elemental analysis, XRD, C(13) MAS NMR, FT-IR, SEM, TG, TEM, and N2 adsorption-desorption techniques. Results showed that the propyl-SO3H and arene-SO3H groups were successfully tethered on the SBA-15 support, and the ordered mesoporous structure of SBA-15 silica was well retained after the organofunctionalization. This organic-inorganic hybrid material displayed high surface acidities and high activities in the acidolysis of soybean oil with caprylic or capric acid to produce SLs containing MCFAs. The influences of processing parameters on the reaction were investigated. The two studied catalysts showed an excellent recyclability for the reaction.

Dehydrogenative coupling of alcohols and carboxylic acids with hydrosilanes catalyzed by a salen–Mn(v) complex

A manganese–salen complex is shown to be effective in catalyzing the dehydrogenative coupling of hydroxyl groups with hydrosilane.

Highly efficient etherification of silanes by using a gold nanoparticle catalyst: remarkable effect of O(2)

O2 is acting! A nanosized hydroxylapatite-supported Au nanoparticle (NP) catalyst exhibited high activity under aerobic conditions, and various silyl ethers could be obtained from diverse combinations of silanes with alcohols. Moreover, O2 was found to act not as a stoichiometric oxidizing reagent, but as a non-consumed promoter, significantly boosting the catalytic activity of AuNPs.