The structural properties of boehmite produced by hydrothermal oxidation of aluminum micron powder at 230-360 degrees C and 3-20 MPa in experimental flow reactor were studied depending on synthesis temperature. It was found that temperature increasing leads to less-ordered structure, particle agglomeration increasing, average crystal size increasing, specific surface decreasing, micropore volume decreasing and mesopore and macropore volumes increasing that corresponds with each other and correlates with the results of kinetic experiments. It was shown that reaction rate and conversion degree is given not only by temperature factor but also by product structural properties, which influence on the diffusion of water to the surface of reactive aluminum. It was shown an important role of flow reaction system in the providing of high rate of hydrothermal oxidation of aluminum and its conversion degree. The results of analysis of structural properties of boehmite confirmed in general that hydrothermal oxidation of aluminum is a promising method of the production of catalyst carriers and sorbents. It was established the possibility to assign the structural properties of nanocrystalline product by thermodynamic parameters within the experimental reactor. The results of mass spectrometric analysis showed that total impurity concentration in produced boehmite decreases in comparison with initial aluminum powder. (C) 2012 Elsevier B.V. All rights reserved.