Reactor and fittings: a) initial design for optimization; b) upgraded design (left) for simulation and schematic diagram of furnace with heater zones (right) (1 condenser; 2 gas and vacuum pipeline flange; 3 fluoroplastic lining; 4 input crucible support; 5 distillation funnel; 6 distillation crucible support; 7 second distillation crucible; 8 first distillation crucible; 9 loading crucible; 10 loading crucible cap; 11 distillation section poles; 12 distillation section flask; 13 quartz flask (reactor); 14 input crucible; 15 corundum muffle; 16 heaters)