PhD Dissertation: Investigation on the Reactivity of 1,3-bis (Chloromethyl) Tetramethyl Disiloxane: 1-Interaction with Lewis Acidic Metal Salts; 2-Application in Ionic Liquids

Jul 05 2018 02:00 PM - Jul 05 2018 04:00 PM

Abstract 

This research explored the reactivity of 1,3-bis-chloromethyl-tetramethyl-disiloxane which is a commercially available chemical with an amine. Two different compounds can be prepared by utilizing this chemical as a substrate, using two different methods. 

The first part will discuss the synthesis of a new bipodal amino siloxane ligand which was achieved by the reaction of bis-chloromethyl-tetramethyl-disiloxane with t-BuNH3 in the presence of n-BuLi. The new ligand, of t-Butyl-[3-(t-butyl amino-methyl)-1,1,3,3-tetramethyl  disiloxanylmethyl]-amine (L1), is a model ligand designed to simulate the surface organometallic complexes (SOMC) model of silica support and bipodal amido ligand that has been presented by the Basset group. Hence, developing this type of siloxane ligand and their complexes will be valuable in the synthesis of new homogenous catalyst, studying the reactivity and attempt to connect them with the SOMC examples. The result showed that the reaction of  L1 with several Lewis acids afforded several uncommon dimer and cluster complexes in the solid state. 

The second part of this research found that heating of bis-chloromethyl-tetramethyl-disiloxane with a 4-6 equivalent of amine, affording 4-N-Alkyl-tetramethyl- oxazadisilinane as six heterocycle ring by using a new simple and neat method. Using six different amine functional groups afforded  six new oxazadisilinane compounds with different alkyls substituted.

Each oxazadisilinane compound was utilized and reacted with four different acids, affording a series of twenty-one examples of new siloxane protic ionic liquids (Si-PILs). Also, the reaction of the cation with methyl iodide provided two examples of siloxane aprotic ionic liquids (Si-AILs). The new family of Si-ILs was well characterized by using NMR, mass, melting point, elemental analysis, and thermal gravimetric analyses. Additionally, twelve crystals were suitable for X-ray diffraction as Si-PILs and one for Si-AILs. By studying their chemical and physical properties, a Maha

Finally, one group of the new Si-PILs was used for butyl acetate esterification. The 5-X group of new Si-PILs salt was tested for esterification of butanol with acetic acid by thermal heat and under microwave irradiation. The salt 5-BF4- showed a good result in both systems with easy separation from the reaction mixture and recyclability is discriminated the 5-BF4- as a good catalyst for the esterification reaction.