N-methylmorpholine-N-oxide Monohydrate Research Articles

An Analysis of Lyocell Fiber Formation as a Melt–spinning Process

In order to gain an understanding of the process of Lyocell fiber formation, the melting and solidification behaviors, heat capacity and density of cellulose N-methylmorpholine-N-oxide monohydrate (NMMO-MH) solutions were studied by differential scanning calorimetry (DSC) and dilatometry, and the diameter development of Lyocell fibers in the air gap was measured online. It was found that the Lyocell process can be considered as both a melt–spinning process in the air gap and a wet-spinning process in the coagulation bath. Cellulose chains in the solutions hindered the crystallization of NMMO-MH, and the melting point of the solutions decreased with increasing cellulose concentration. The density of cellulose NMMO-MH solutions decreased linearly with increasing temperature in the solid or the liquid state, and it increased with increasing cellulose concentration. The heat capacity of the solutions increased slightly with increasing temperature and concentration. The development of fiber diameter, the velocity gradient, and the gradient of the filaments in the air gap were limited to a short distance from the spinneret orifice. The position at which the velocity and the tensile stress gradient reached their maximum values moved closer to the spinneret orifice with increasing take-up speed.

Synthesis of 17β-[4-(1,3-thiazolyl)]androstane 3β-hemisuccinate and glycoside

The protected 20(21)-en-20-ol ether III was oxidized with N-methylmorpholine N-oxide monohydrate and osmium tetroxide to give the hydroxy ketone IV which was converted into the bromo derivative VIII via the mesylate VI. Hantzsch reaction of the bromo ketone VIII with ethyl thioxamate afforded the thiazole XI whose hemisuccinate XIII and glycoside XV were prepared.

Synthesis of 4-(21-nor-5-pregnen-20-yl)-1,3-thiazole derivatives

The keto sulfoxide IV, prepared from the ester III, was reduced with amalgamated aluminium to give the ketone V which after enolization and silylation afforded the silyl enol ether VI. Oxidation of VI with osmium tetroxide and N-methylmorpholine N-oxide monohydrate yielded the α-hydroxy ketone VII. This was converted into the mesylate IX and further into the bromo ketone XI which on Hantzsch reaction with ethyl thioxamate furnished the steroidal thiazole XII. Compound XII was converted into the hemisuccinate XIV.

Cellulose organic solvents. I. The structures of anhydrous N-methylmorpholine N-oxide and N-methylmorpholine N-oxide monohydrate

Cellulose organic solvents. I. The structures of anhydrous N-methylmorpholine N-oxide and N-methylmorpholine N-oxide monohydrate