What is superctitical water?

The water becomes supercritical phase when the temperature and pressure exceed over critical point (374C, 22MPa). The supercritical water has no boundary between the gas and liquid phase. The density of supercritical water is lower than that of the liquid water and extremely higher than that of the water vapor. The polarizability of the supercritical water is low as like organic solvents.

Phase diagram of water

Schematic diagram of water molecules

    Nano-particle synthesis using supercritical water    

Metal salt solutions are commonly used in nano particle synthesis. However, these aqueous solution is not miscible with many organic solutions. On the other hand, the supercritical water has a low relative permittivity (2-10) and is easily mixed with organic solvents. This provides the homogeneous reaction field and thus an organic modified nano particle synthesis can be achieved.

    Supercritical hydrothermal synthesis    

The metal salt solution at room temperature is mixed with supercritical water and heated rapidly. Then the metal oxide nano particles are produced by hydrolysis of metal ion. When an organic compound as modifier is introduced into this system, the surface of the nano particles can be organic-modified.

If you already have particles which should be organic modified, our system is available. The particles is feeded by slurry pump into the reactor of MOMI-cho system. At that time, organic compounds also put into the system and then the particles are organic-modified.

Our system can be set flexibly. For example, the following flow lines are required in some cases.

Our products

Our supercritical hydrothermal synthesis system "MOMI-cho series" can treat several reaction continuously. You can flexibly customize the flow line and mixing point to change the heating rate and the reaction time. We have several scale of hydrothermal synthesis systems as follows.

  MOMI-cho mini MOMI-cho mini II MOMI-cho MEGA MOMI-cho GIGA
Feature Lab. scale
Lab. scale
(two-zone heating)
Middle scale Large scale
max Temperature (C) 450 450 (two zone) 450 450
max Pressure (MPa) 30 30 30 30
Flow rate (ml/min/line) 10 10 160 200
Size (w/o chiller) W1500 x D600 x H2000 W1760 x D750 x H1800 W3050 x D1080 x H1800 W8700 x D1700 x H2200
Heat exchanger No No Yes Yes
Slurry pump Optional Yes Yes Yes
Electricity AC100V, 15A AC200V, 20A AC200V, 125A AC200V, 150A

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