Год выпуска

Номер выпуска

Язык статей

Сортировка

2018, №2

сс. 3-14

Articles

Effect of Reagents on the Properties of Barium Titanate Synthesized in Subcritical Water

A.A. Kholodkova, M.N. Danchevskaya, Yu.D. Ivakin, G.P. Muravieva, S.G. Ponomarev.

Quote

Key words: synthesis of barium titanate, subcritical water fluid, barium titanate nanocrystals

The structure and morphology of fine-crystalline barium titanate synthesized in a
subcritical water fluid at 230 °C and 2.9 MPa were studied. Barium oxide, barium hydroxide
octahydrate Ba(OH)2 ⋅ 8H2O and two modifications of titanium dioxide (rutile and
anatase) were used as starting reactants. Relationships between the composition and
properties of the reactants and the characteristics of the product (barium titanate)
were revealed. They indicate that the product structure in the subcritical water is
formed via a solid-phase mechanism.

doi:10.34984/SCFTP.2018.13.2.001

2018, №2

сс. 15-23

Articles

Key words: subcritical water, antioxidant, quercetin, rutin, hydrolysis, buds, sophora japanese, Sophora japonica L.

The possibility of obtaining quercetin (a natural antioxidant) from buds of Sophora
japonica
L. using subcritical water, which acts as a solvent and a reagent simultaneously
was studied. The suggested approach avoids the use of expensive and toxic organic
solvents, does not require separate extraction and hydrolysis steps and simplifies the
purification of the product. A 13-fold reduction in treatment time was achieved compared
with the traditional procedure to obtain high yield of quercetin. The loss of the target
product in the production of the dried extract was reduced.

doi:10.34984/SCFTP.2018.13.2.002

2018, №2

сс. 24-39

Articles

Key words: hydroxybenzoic acids, hydroxycinnamic acids, supercritical carbon dioxide, cosolvent, molecular dynamics, hydrogen bond

Selective solvation of hydroxybenzoic (ortho-, meta- and para-hydroxybenzoic,
protocatechuic, gallic, syringic) acids and hydroxycinnamic (para-coumaric, caffeic)
acids by polar cosolvent (methanol) in supercritical carbon dioxide at temperature
318 K, solvent density 0.7 g/cm3 and methanol concentration 3.5 mol.% is studied
using molecular dynamics method. The subject of the study is the formation of cosolvent
clusters around solute, the solute — cosolvent hydrogen bonding, the structural features
of hydrogen-bonded complexes associated with the molecular structure of solute (the
number and location of hydroxyl groups, the substitution of hydroxyl hydrogens by
methyl groups, and the presence of ethylene group between carboxyl group and
benzene ring).

doi:10.34984/SCFTP.2018.13.2.003

2018, №2

сс. 40-49

Articles

Key words: palladium catalyst, impregnation, supercritical carbon dioxide, hydrogenation

The synthesis of palladium and palladium-silver catalysts using supercritical fluid
CO2-impregnation process (static mode) was investigated. It is shown that the maximum
amount of metal is impregnated to the carrier in the temperature range 318—323 K
and pressure range 19.0—23.0 MPa. The activity of palladium catalysts prepared according
to the proposed method is comparable with the activity of industrial samples currently
produced.

doi:10.34984/SCFTP.2018.13.2.004

2018, №2

сс. 50-55

Articles

Key words: polymers, supercritical fluids, subcritical freons, carbon dioxide.

Process of saturation of ultra high density polyethylene with sub- and supercritical
freons and supercritical carbon dioxide was investigated for the first time. It was
shown that subcritical freon R22 can be absorbed in much larger amounts by these
polymers than subcritical freon R410а, as well as supercritical R23 and carbon dioxide,
which makes it promising for use in the processes of impregnation and sterilization
of polymers.

doi:10.34984/SCFTP.2018.13.2.005

2018, №2

сс. 56-68

Articles

Key words: supercritical fluid impregnation, fluorescence microscopy, photoactive compounds

Fluorescence microscopy was used to study the distribution of photoactive compounds
(PAC) in polymer matrixes impregnated in supercritical carbon dioxide (SC-CO2). It
is shown that the character of the PAC distribution in polymers depends on the
nature of the matrix, the degree of interaction of the introduced compounds with
polymer fragments, and the sizes of the photoactive compounds corresponding diffusion
coefficients. Such information may be in demand for the development of functionally
oriented polymer systems impregnated with РAС (heterogeneous catalysis,
photochromic materials, medicine).

doi:10.34984/SCFTP.2018.13.2.006

2018, №2

сс. 69-74

Articles

Small Volume Cyclone Separator for Supercritical Fluid Extraction

K.B. Ustinovich, D.I. Prokopchuk, O.I. Pokrovskiy, O.O. Parenago, V.V. Lunin.

Quote

Key words: cyclone separator, supercritical fluid extraction, extract recovery

A low-volume cyclone separator with changeable extract collection reservoirs for the
supercritical fluid extraction is designed. A method for manufacturing the designed
separator by 3D-printing from an available polymer is proposed. It is shown that the
designed small volume separator allows for a greater extract recovery compared to a
standard large volume cyclone separator in the supercritical fluid extraction.

doi:10.34984/SCFTP.2018.13.2.007