JP2003053197A - Design of novel material having method of use to give rise to chemical bond by using descriptor of chemical bond - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an estimation (approximation) method for characteristics in use like the activity of a catalyst in a solid inorganic matrix of material MAB of which, for example, the active element is AB or the force to confine a radioactive isotope element. SOLUTION: This method includes the use of a descriptor DAB of the chemical bond between A and B having the flank of energy and an index RAB for measuring the use characteristics of the material described above. The method of measuring the chemical affinity over the entire part of the element or the element B for the matrix A by the descriptor DAB is provided. This method may be used advantageously for the design of the novel material and the formation or the change of at least one chemical bond is brought about or the formation of the bond described above can be averted by its use.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method of estimating the property of use of a substance M _AB whose active element is AB, such as catalytic activity in a solid inorganic matrix or the ability to contain radioisotopes. Regarding
The invention further relates to a method for determining the chemical affinity of an element or group of elements B for matrix A, such as the affinity of a substance for oxygen- or sulfur-containing compounds or halides. This more or less important affinity makes it possible to characterize the resistance of the substance to corrosion by, for example, sulfur-containing compounds or halides or by oxidation. Many other applications of these methods are possible. Some of them will be detailed later. More generally, therefore, the method according to the invention leads to the formation or modification of at least one chemical bond characterized by the descriptor D _AB or to the use which requires avoiding said bond formation. It enables the selection or design of new substances possessed.

[0002]

PRIOR ART In the present prior art, the selection or design of materials for a particular application has only been considered on an experimental basis, according to trial and error. This approach is naturally long and costly. Any method that makes it possible to significantly reduce this exploration step presents technical and economic advantages.

The vast majority of the use properties of substances are, to a large extent, directly determined by the cohesive forces inherent in their composition. That is, for example, the case for the mechanical properties of metals and their alloys, ceramics, and structural materials (elastic modules, puncture resistance, hardness, etc.), or even for radioactive activity in inorganic structures for storage purposes, for example. This is the case when the main element, which is effectively used for capturing the element, is soluble. These chemical cohesive forces also determine all surface properties of the material. The technical importance of the substance is known to the person skilled in the art. The coefficient of friction,
Such as abrasion resistance, corrosion action, oxidation resistance, adhesion, wettability, and catalytic activity.

Furthermore, the chemical cohesive forces dominate the local atomic structure of the material and, consequently, its electronic structure and any physical properties derived therefrom (electron, optical, magnetic, etc.). As such, the search for new high temperature superconducting phases of electrical current, or even for new solid electrolytes with improved ionic conductivity for the production of more efficient fuel cells, has led to the search for compounds with special local mechanisms. Return to quest (eg JB Goodenough, Nature, Volume 404, April 20, 2000)
Sun, pp. 821-822, and citation).

Those skilled in the search for the specific application of new substances rely as much as possible on the knowledge and methods laid down by the scientific discipline that is today solid state chemistry. The latter quantifies the relative stability of the structure under constant temperature and pressure conditions based on the standard concept of enthalpy of formation.

The standard enthalpies of formation of a large number of compounds have been experimentally determined and tabulated. The enthalpy makes it possible to create useful so-called "phase" diagrams, for the purpose of locating areas of experimental conditions, for example. Within these regions, there are stable structures of interest. Therefore, these source data and charts have limited values for the invention of new stable phases in the defined areas of use. Thus, at best, those skilled in the art will draw conclusions from known structural and compositional phases by analogy and chemical intuition.

[0007] In order to logically guide its action, scientists practicing the synthesis of organic or inorganic compounds came up with the concept of chemical affinity from an early stage. Then, when the atomic structure of matter was established, the concept of interatomic bond strength was developed. Modern theoretical chemistry focuses on the structure of quantitative prediction theory of chemical bonds within atomic, molecular or crystalline structures.

Quantum physics provided the basis for mathematical theory. The extreme precision of the theory proves in a much wider area as the increasing power of electronic computers enables digital elucidation of constituent formulas for more complex chemical compositions. To be done. So-called “ab initio” computational techniques are not hindered by the prior knowledge of empirical data sources, so these techniques are used to study the chemistry of a particular composition prior to any synthetic experiment in the laboratory. It has been developed for at least 20 years to the extent that it could be considered useful for predicting structural stability, geometry, and physical and chemical properties.

Although this “design of computer-assisted materials” is a very active area of research in methodologies, there are only a very limited number of actual successes.
These successes are limited to special cases. To develop a hydrocarbon reforming catalyst with improved stability, for example by using vapors based on metallic nickel and by selective loading of gold atoms on the surface (F. Besenbac
her et al. Science, 279, 1913-1915, March 1998.
20 days), or even to reveal cathode compositions that significantly improve voltage and reduce the weight and cost of lithium batteries (G. Ceder et al, Nature, 3
92, 694-696, April 16, 1998). These recent successes rather exemplify the computationally proven approach of intuitive source design, which has been empirically confirmed by experimental measurements.

The economic benefits of such developments have not been clearly demonstrated at this time. However, by any person skilled in the art, the superiority of the principle based on trial and error preliminary experiments is given to them. The realization of it depends on the speed and cost of the calculations performed.

From this point of view, advances in the integration technology of electronic circuits anticipate a decisive and astonishing breakthrough in the near future due to the rapid increase in computing power over time at a particular cost. Unexpectedly, the method according to the invention is envisaged in this direction as a rapid ab initio calculation method for quantitative descriptors of chemical bonds in crystalline solids. This allows the latter to be classified according to their degree of efficiency for multiple applications of the first technical importance.

A strategy for the preliminary exploration of new materials, which is considered to be the exact opposite of the "design of computer-assisted materials" defined above, consists of "combinatorial chemistry" which has emerged since several years (eg US patent). US-A-5959
297 and US-A-5985356), which makes sense when combined with the so-called "high flow experimental" technique. In this case, the idea means to experimentally systematically predict the gap between predefined compositions and conditions of synthesis. The substances resulting from these systematic combinations are just sufficient and prepared in very small quantities for tests that allow classification according to the desired property or properties. Combinations that pass the test allow redefining a more limited predictive gap. Within the gap, the combinatorial synthesis and testing procedure may be repeated to screen the identification of combinations that match the original target. Thus, the found combination or combinations will be synthesized in larger quantities to accurately measure its use properties.

The approach to "combinatorial chemistry" is
Recently, it has been the subject of considerable investment that has led to significant technological developments. In this context, information technology facilitates the management and tracking of properties of a large number of samples synthesized and tested at high tempo. In addition, the information technology enables the operation of high tempo and generally robotized synthesis and testing processes. To date, the targets of “combination chemistry” are, for example, new molecular drugs, new luminescent substances (US-A-6013199), new polymerization catalysts (US-A-6034240, US-A-6).
043363), a new material with high magnetic resistance (US-A-5776359), or even a new heterogeneous catalyst (SMSenkan dans Natur).
e, vol. 394, pp. 350-353, July 23, 1998).

By those skilled in "combination chemistry",
Random exploration of combinatorial areas was rapidly recognized as generally showing a very low success rate, which resulted in a risk that was not well-balanced by a very large number of experiments. Therefore, an improved method was provided. These are attributed to guiding inquiry through an element of a priori knowledge. Furthermore, the classification cycle may be considered as an input of knowledge that allows to better guide the next classification cycle. That is why Baerns et al. Proved the usefulness of, for example, so-called artificial evolution procedures (Baerns et al.
Conference sur lesapproches comb organized by The Knowledge Foundation (Fondation du Savoir)
inatoires pour la decouverte de nouveaux materiaux
(Lecture on "combinational approach for discovering new substances" (Study group)), San Diego, CA, USA, 2000
January 23-25).

Another method develops a quantitative structure-property relationship (RQSP) by correlating the performance index by the desired property with a group of digital parameters that identify each compound and are called "descriptors". Is to let. The descriptor is generally generated by theoretical calculation. That is, molecular weight, molecular volume, geometrical form factor, moment of average distribution of charge, topological index, such as “Catalyse combinatoire et h
aut debit de conception et d'evaluation decatalyse
urs '' (Combinatorial catalysis and high throughput
JM Newsam, Se in catalyst design and testing)
ries de publication NATO ASI, Editor-in-Chief EG Derouane,
See Editeur Kluwer Academic, Dordrecht, 1999.
Modern linear or non-linear regression methods often make it possible to establish a good correlation between the performance index and the multivariate mathematical function of the constrained descriptor group. Such correlations can guide combinatorial exploration into chemical structures with theoretical descriptors that maximize the ability to model theoretical models of performance indices. However, the theoretical descriptor method is practically applied almost exclusively to molecular compounds, and no example of descriptors to crystalline substances is known.

Research work by the inventors of the present invention has described the initial descriptor design of the energy of metal-sulfur bonds in sulfides of transition metals and their use to characterize the catalytic activity of such sulfides. Already published (Catalysis i Today) (La Catalyse Aujourd'hu
i), 50, 629-636, 1999, French patent FR-27
58278) H. Toulhoat et al.). However,
This initial descriptor is defined in those documents as the ratio of the sticking energy of a solid per unit cell to the number of types of bonds considered identifiable by the unit cell. This provision differs from and is not derived from the provision provided for descriptors according to the present invention.

[0017]

SUMMARY OF THE INVENTION The present invention describes how a family of theoretical descriptors of chemical bonds between atom pairs in any crystalline solid may be used to find new solids with particular applications. It is described whether it can be used. Unexpectedly, these novel descriptors have predictive capabilities with regard to a number of technical use properties of crystalline solids, such as catalytic activity or even suitability for storage of radioisotopes.

The invention applies to all forms of preliminary quest for new substances. The intended property of the novel substance may have a correlation with the descriptor for which the calculation method is specified. The present invention shows particular advantages when using the novel technique for high flow rate synthesis and classification, especially to find active substances in solid form which are crystalline or partially crystalline.

The present invention relates to a method for estimating from a descriptor certain specified use characteristics of a substance M _AB whose active element is AB. This descriptor is a calculated quantification associated with each substance and may correlate with the use characteristics of said substance. This use characteristic is estimated by the index R _AB , which is determined using the method according to the invention. Thus, if the use of a substance is catalytic, its use characteristics (catalytic activity) may be quantified by measuring the rate of the reaction or conversion reaction catalyzed. If the use property studied is the corrosion resistance of a substance, this property can be quantified using, for example, the oxidation rate of said substance. The descriptor has the dimension of energy and in the substance of the general formula AB, an element or an element group B,
It is considered to represent the chemical bond energy with the element or element group A.

[0020] Thus, the method according to the invention is estimated to Gaishitsu methods of use properties of the material M _AB active element is AB. Therefore, by the method according to the invention, the substance M
It is possible to determine the index R _AB which constitutes an estimate of the use characteristics of the _AB.

The method comprises the following steps: (a) substance group M
The step of determining the value of the descriptor D _XY for the substance group M _{XY in} which the active element of xy is XY, and the index R _XY for measuring the use characteristics of the substance is known, (b) correlation R _XY = f Chart or stage of mathematical expressions _{(D XY),} descriptor _{D AB} regarding (c) material _{M AB}
And (d) the value D _AB of the correlation R _XY
= F (D _XY ), or by using the mathematical representation of the correlation
_It includes the step of determining the index R _AB which constitutes an estimation of the usage characteristics for _AB .

Furthermore, according to the present invention, the chemical affinity of the element or element group B for the matrix A consisting of another element or element group, for example, the affinity of carbon for metal for forming carbide, or for forming oxide. It is possible to determine the affinity of oxygen for metals.

[0023]

DESCRIPTION OF THE INVENTION The present invention describes a method of designing and / or selecting substances for a predefined use. In fact, the method according to the invention makes it possible to estimate the use properties and therefore the performance level of the substance in this use, for example for applications in heterogeneous catalysts. Furthermore, it becomes possible to determine the chemical affinity of the entity A consisting of at least one chemical element with respect to the matrix B consisting of at least one chemical element.

The method according to the invention is based on a quantitative calculation which measures the affinity of a substance for a particular chemical element. Thereby, it is possible to predict a particular usage characteristic. This use can be carried out, for example, by the Sabachi known in the art.
It may be heterogeneous catalysis according to the tier principle, storage of radioactive elements by insertion into an inorganic matrix, promotion of adhesion or wetting, adhesion and associated mechanical properties, and corrosion resistance. This list is not limiting.

In general, any use that gives rise to a chemical affinity of an element or group of elements that exists for another element or group of elements, either to select a new substance for this use, or of the chemical affinity of the element or group of elements. It may be studied using the method according to the invention to determine the extent.

In the method according to the invention, an algorithm or calculation method and D with energy dimension
_XY (or _DAB ) type quantities are used. General formula XY
Each of these quantities, called a chemical bond energy descriptor in the substance (or AB), is contained between the element Y (B) and its complement X (A). X, Y, A or B may be composed of any number of atoms and have a varying stoichiometry. Thus, for example, the method according to the present invention may be used to produce a carbide M ₃ C (AB) between a carbon atom C (element B) and a group containing _three metal atoms M ₃ (element group called A). It can be applied in the case of the measurement of affinity. Furthermore, the process according to the invention is carried out by using two metal atoms M in order to produce the oxide M ₂ O ₃ (AB).
_{For a} group composed of ₂ (called a group A), a group composed of _three oxygen atoms O ₃ (a group of elements called B)
It is also applicable when measuring the affinity of
Other illustrations are described below, particularly in the examples.

The crystal characteristics of the substance XY are crystallographic data.
If available in the base, the descriptor D _XY and / or the descriptor D _AB may be calculated using the method P1 comprising the following steps: (a1) substance XY (or AB in the experimental crystallographic data base. (A) Crystallographic feature identification step, (a2) XY (or AB) Brave crystal lattice (lattite) total energy per unit cell calculation step, (a3) Optimal unit cell XY (or AB) Constructing a quasi-unit cell X (or A) obtained by removing (a
4) _A step of calculating the total energy E _X (or E _A ) per unit cell of the Brave crystal lattice of _X (or _A ),
(A5) Complement X of the optimum unit cell XY (or AB)
Constructing a quasi-unit cell Y (or B) obtained by removing all atoms belonging to (or A), (a6)
Calculation step of the total energy E _Y (or E _B ) by the unit cell Y (or B) of the Brave crystal lattice of B, (a
7) A step of determining the number n of X (or A) atoms existing in the first coordination sphere of Y (or B) atoms in the optimum unit cell XY (or AB), (a8) optimum unit cell XY (or AB) ) per Y (or B) number b determining step of the atoms, and (a9) the following _{equation: D XY = [E XY -} (E X
+ E _Y )] / nb (or D _AB = [E _AB − (E _A +
Descriptor D by applying E _B )] / nb)
_XY (or D _AB ) calculation stage.

Furthermore, the descriptors D _XY and / or D _AB may be calculated using method P2, but are not exclusive if, for example, the crystallographic characteristics of substance XY are not available in the crystallographic data base. .

Method P2 includes the following steps: (a
1) Material XY (or A) by analogy with existing structures or in the database of experimental crystallography
B) identification step of crystal characteristics, (a2) XY (or A
B) step of calculating the total energy per unit cell of the Bravais crystal lattice, (a3) minimizing the total energy and total energy E depending on the calculation method employed.
Optimal unit cell XY (or A of _XY (or E _AB ).
B) iterative search step for unit cell parameter values of the structure, (a4) quasi unit cell X obtained by removing B-type atoms from the optimum unit cell XY (or AB)
(Or A) construction step, (a5) calculation step of total energy E _x (or E _A ) per unit cell of the Brave crystal lattice of _A , (a6) complement X (or AB) in the optimum unit cell XY (or AB) Or a step of constructing a quasi-unit cell Y (or B) obtained by removing all atoms belonging to A), (a7) total energy per unit cell Y (or B) of the Brave crystal lattice of Y (or B) _EY
(Or E _B ) calculation step, (a8) Optimal unit cell X
Determining the number n of X (or A) atoms present in the first coordination sphere of Y (or B) atoms in Y (or AB),
(A9) Y per optimum unit cell XY (or AB)
(Or B) a step of determining the number b of atoms, and (a10)
The following formula: D _XY = [E _XY − (E _X + E _Y )] / nb
(Or D _AB = [E _AB − (E _A + E _B )] / nb)
Descriptor by applying _{D X Y} (or D
_AB ) calculation stage.

Thus, for the implementation of the method of estimating a use characteristic according to the invention, comprising steps (a) to (d), only method P1 or only method P2, or even method P1 at times. And at some other time method P2
Are used for the calculation of various descriptors.

Methods of identifying crystallographic features are known to those skilled in the art. This identification method is composed of the coordinates of these three unit vectors a, b, and c in the three-dimensional space of Euclidean geometry; then, the group of atoms that form the asymmetric unit cell, and the three vectors a, b, and c. Elemental unit cell of the Brave crystal lattice of a crystal according to their coordinates in a reference; and finally a whole symmetric operation to be applied to the atomic positions of the asymmetric unit cell to restore the entire atomic position of the unit cell. Is to measure. The infinite complete crystal structure is completely determined by the unit cell tanslation operation in space along the three vectors a, b and c. The entire symmetry operation, except for three translations, forms an atomic group in the sense of the mathematical theory of atomic groups, called a space group. The number of these groups is finite and their terminology is listed.

Experimental techniques which allow the determination of the crystalline characteristics of crystalline compounds (also called crystalline substances) rely on electromagnetic waves such as X-rays or the diffraction phenomena of fine particles such as neutrons. John Wiley and at Chichester in 1991
Edited by Sons, Professor J. Eberhart's book "Structure et analysis."
imique des materiaux '' (Structural and chemical ana
lysis of materials) is referred to for the description of the theoretical and technical basis for the determination of the crystalline characteristics of solids. A large number of crystalline characteristics of substances have been determined experimentally and are publicly accessible in databases such as Institut.
de Chimie Minerale Gmelin and Karlsruhe from Germany
Le Center d'Informations Factuelles (Gmelin-Insti
tut fuer Anorganische Chemie et Fachinformationsze
`` Base de donnee des Struc
tures Cristallines Minerales '' (Inorganic Crystal S
tructure Database ou ICSD) or even the "Crystmet" base created by the group of Professor John R. Rodgers in Ottawa, Canada. These two databases are especially USA (CA), CA92057, Oceanside, PalermoDrive 5031, SciCo In
c. Company and Le Mans, France, 72000, avenue FABarth
It is sold in electronic form by oldi, 44 Materials Design SARL.

Determining the structure by analogy from existing structures consists simply in designing a hypothetical structure by substituting atoms of known structure based on chemical similarities known to those skilled in the art. For crystalline materials of the general formula XY (or AB), the number b of Y (or B) type atoms per unit cell is clearly deduced by recognizing the entire atomic position of the unit cell by the method described above. .

The method for calculating the total energy is preferably the substance X in the field according to the periodic Coulomb law determined by the crystal lattice of the atomic core localized in the unit cell.
A solution of the Schrodinger equation describing the behavior of Y (or AB) electrons, more preferably a solution inferred from functional theory of density (eg editors CRACatlow and AK Cheetham, 195).
~ 238, 1997, Nouvelles Tendances dans la Chimie d, published by Kluwer Scientific, Dordrecht.
es Materiau ”(New trends in materials chemistry) by E. Wimmer).

The method for determining the number n of X (or A) atoms existing in the first coordination sphere of Y (or B) atoms in the optimum unit cell of XY (or AB) is defined as follows. That is, the method is according to the method described above,
Data on the entire atomic positions of the atoms constituting the unit cell of the XY (or AB) crystalline substance is required. The Y (or B) atom is selected. The location of the center of the material is chosen as the center of the so-called "first coordination sphere". Its radius is usually set to a value that corresponds to the length of the chemical bond, ie about 0.05 to 0.4 nanometer, preferably 0.1 to 0.3 nanometer, to give Y (or Incorporate a first neighbor atom of Y (or B) located at the same or a comparable distance of B).

The present invention particularly relates to a method E _P for estimating the use characteristics of the substance M _AB whose active element is AB. In fact, it is possible with the method according to the invention to determine the index R _AB which constitutes an estimate of the use properties of the substance M _AB .

[0037] The method _{E P} comprises the following steps: (a) a active element is XY, descriptor D for material _{M XY} group having a known index _{R X Y} for measuring the use properties of the material _The step of determining the value of _XY , (b) the step of tabulating or mathematically expressing the correlation R _XY = f (D _XY ), (c) the descriptor D for the substance M _AB
By recording the calculation step of _AB and (d) the value D _AB in the form of the correlation R _XY = f (D _XY ), or by using the mathematical expression of said correlation M
Decision step index R _AB which constitutes an estimate of the use characteristics related to _AB contains.

Unexpectedly, the descriptor D _AB makes it possible to estimate the value of the use characteristic for the substance M _AB . The active element of the substance is a crystalline or semi-crystalline chemical substance A related to the descriptor.
B.

Experimental values of the index R _XY for measuring use properties, such as the intrinsic reaction rates with which the activities of pure transition metals can be effectively compared, are, for example, the hydrogenation of ethylene or other olefins, the hydrogenation of benzene. Such as hydrogenation of carbon monoxide, steam dealkylation of toluene, alkylation of paraffins or aromatics, hydrotreating, isomerization, hydrocracking, selective hydrogenation or reforming reactions of diolefins and acetylene A large number of reactions with industrial merits are available in the literature. This example is not limiting.

A number of attempts have been made to correlate these rate data with various descriptive parameters of the metal or with various quantities that measure the physical and chemical properties of the metal. To date, no convincing guide to the person skilled in the art for identifying new catalyst compositions which will have a higher reaction rate than previously recognized can be provided.

It is very unexpected that, depending on the descriptor D _XY according to the present invention, the activity value (index R _XY ) in various chemical reactions is shifted so that the activity located at a different place depending on the chemical reaction. It has been proved that a volcanic curve with a maximum value Rmax of is obtained. The main curve with the maximum of the characteristic shape corresponds to each chemical reaction. The abscissa of this maximum is characteristic in its own right. It is now possible to calculate the descriptor D _AB corresponding to the new catalytic material M _AB . It is also possible to provide the reaction rate R _AB of the catalytic material in the desired chemical reaction, either with respect to the main curve or with respect to the calculation by using the mathematical expression of the correlation R _XY = f (D _XY ).

Thus, for example, in a number of transformation reactions of molecules containing carbon, the use properties of the index R _XY , which in this case is the catalytic activity level of the alloys of metals and transition metals (as measured, for example, by chemical kinetics). Is the descriptor D for the curve of the metal M considered.
It is found to be correlated with _MC . For example,
When MαC is a carbide of a transition metal, the energy of the metal-carbon bond is described in D _MC . It is found that there is a correlation between the descriptor D _MC and the intrinsic catalytic activity of the metal M, which is experimentally measured for a number of reactions of practical benefit. Therefore, it is possible to a priori find the activity of another metal or metal compound by calculating the corresponding descriptor.

These correlations can be found in Saba known to those skilled in the art.
It seems to follow the tier principle. According to this principle, when a particular chemical reaction rate V is considered, all other things are the same in the presence of a series of substances with surface areas capable of catalyzing the reaction, Is maximum with respect to the interaction force F between the reactants and the surface area which is neither too large nor too small. If the person skilled in the art is able to join each point of the experiment in the plane of the coordinates V and F, a very sharp maximum curve, commonly called the term "volcano curve", is obtained. Obtained (eg Prof. M. Boudart's paper: le Manuel de Catalyse Heterogene (Handb
(Principes in ook of Heterogeneous Catalysis)
de Catalyse Heterogene '' (Principles of heterogeneo
us catalysis) 1 to 13, Editor-in-Chief G. Ertl et al., Editor Wiley-VC
H, Weinheim, 1997).

In another field of application, it becomes clear that D _AB is the outstanding descriptor of the poisoning of the catalyst of composition A by element B.

The descriptor D _AB has a number of applications in the design of materials, especially when a priori search that links space-exploration of chemical compositions with high-flow experiments is considered. That is, a priori calculation of the descriptor D _AB , which is correlated alone or in combination with the intended use properties, makes it possible to eliminate a large number of compositions without merit and Significant savings can be made by assigning empirical proofs only to those compositions that have the merit, predicted by the descriptor (s) of the method according to the invention.

The various calculation steps of the descriptor are carried out, for example, by using an electronic calculator or a computer,
This may be done using any means known to those of skill in the art. Preferably, information means capable of automating all or part of the steps of the method according to the invention and various calculations are used.

Intrinsic experimental values of reaction rates that can reasonably compare the activities of pure transition metals are, for example, hydrogenation of ethylene, hydrogenation of benzene, hydrogenation of carbon monoxide, steam dealkylation of toluene, and other reactions. It can be used in the literature for a number of reactions with industrial merits such as. This example is not limiting and any catalytic reaction
It may be considered in the method according to the invention.

Another very useful application of the invention is residual impurities in the reactants, such as sulfur-containing or nitrogen-containing heteroatom compounds which are difficult to completely separate from the hydrocarbons obtained by distillation of crude oil. To search for a catalyst that resists poisoning by the. Those skilled in the art are aware of the strong toxicity of sulfur or nitrogen atoms (S or N) for transition metal-based catalysts used, for example, in hydrogenation, isomerization or hydrocracking in refining operations. Numerous research achievements have been devoted to the search for alloys or compounds that retain sufficient activity in the presence of such poisons. Descriptor D _MP, where P is the poison element and M is the catalyst composition,
It is possible to make a quantitative classification (proportional classification) of the toxicity of. The person skilled in the art therefore finds a considerable advantage in that only compositions which show a weaker toxicity of the venom P than the known compositions by preliminary calculations with the method according to the invention have to be prepared and tested.

These results, illustrated by the examples below, demonstrate the general effect of the invention in the field of search for new catalysts, but the invention is not limited to this single field.

Artificial radioactive elements with long lifetimes produced by some nuclear reactions constitute a biological hazard and must be contained forcibly. As a very long-term containment means preferred by those skilled in the art, the containment of these elements in solid solutions of minerals with great chemical inertness is subject to experimental and theoretical exploration of activity ( For example, "L'elimination de
s armes au plutonium '' (Disposal of weapons plutoni
um), Editor-in-Chief ERMerz et al., Kluwer Academic Publishing, Dordre
cht, 1996): The solubility of the radioactive element Re in mineral Z is clearly directly related to the binding energy between Re and the atoms that make up the closest neighbors in structure Z. The descriptor D _ZRe calculated using the method according to the invention makes it possible to access this solubility estimation.

The theoretical nature of the calculations allows the estimation of the solubility of Re in existing minerals and the known crystallographic structures in the compositions from which Re isotopes are introduced.
Furthermore, it makes it possible to estimate this solubility when Re is introduced at the insertion or substitution position in minerals with most elements different from Re.
Therefore, the method according to the invention is a very effective means for the more rapid determination of crystallinity, or structures having at least one local atomic order, which are Effective sequestration of metal ions
It is possible to secure (sequestration) (masking).

The invention further relates to a method _AF for determining the overall chemical affinity of an element or element B for a matrix A consisting of at least one element. The method is
Comprising the steps of: (a) a identification of the crystalline characteristics of material AB, total energy calculations per unit lattice of the AB, or the optimum unit cell AB of total energy E _AB
Step of iterative search for the value of the parameter of (b), construction step of quasi-unit cell A by removing B-type atoms of the optimum unit cell, (c) total energy E per unit cell of A
Calculation step of _A , (d) construction step of quasi-unit cell B for removing all atoms belonging to complement A in the optimum unit cell,
(E) A step of calculating the total energy E _B of _B per unit cell, (f) A step of determining the number n of A atoms existing in the first coordination sphere of B atoms of the optimal unit cell, (g) Optimal unit cell Of determining the number b of B atoms in, and (h) formula D
Calculation stage of the descriptor D _AB according to _AB = [E _AB − (E _A + E _B )] / nb). Method _AF may preferably be used for the applications listed below, but is not exclusive. In any case, the experimental data (the crystallographic data for substance XY and the index R _XY for measuring the use properties)
If is well documented in the literature or has been measured previously, then the method E _P may advantageously also be applied in these various cases.

The method according to the invention may be applied to the search for substances which are resistant to various forms of chemical corrosion. In the case of oxidative corrosion, the affinity of a substance for oxygen is studied. Therefore, the descriptor D _AO of the bond between oxygen and the compound A in the substance AO should be minimized.
Is sought. A may be, for example, an alloy of metals.

In order to further investigate substances that are resistant to corrosion by sulfur compounds (classification by the value of descriptor D _AS ) or halogen X (X = Cl, F, Br or I) (classification by the value of descriptor D _AX ) In a similar way, it is possible to carry out the method.

Further, the descriptor D in the hydride AH
By classifying the metal alloys according to the criterion of the minimum value of _AH , it is possible to search for the metal alloy A which cannot be embrittled by hydrogen so much. On the contrary, the search for the element P that promotes the surface hardening and the abrasion resistance due to the friction of the substance A may be effectively advanced by the criterion of the maximum value of the descriptor D _AP in the substance AP.

The search for the element C or the multi-element compound D which promotes the adhesion of the substance A and the substance B is carried out by the descriptor D.
It may proceed by classification according to the criteria of the joint maximum of the _AC and the descriptor D _BC , or even the descriptor D _DA and the descriptor D _DB . Similarly, the search for elements or compounds that promote the wetting of solid A by liquid B is driven by the choice that results in high values of the corresponding descriptor D _AB . Such an approach may be transferred to the search for elements or compounds that promote dewetting or incompatibility, by classification by the joint minimum criterion of the appropriate descriptors.

The invention may also be applied to the search for substances whose properties are known to be determined by the local chemical composition, in particular optical, electronic or magnetic properties.

That is why M. Jansen and HP Lets
chert (Nature, 404, 980-982, April 27, 2000) found new inorganic pigments in the red to yellow range, except for environmentally toxic chemical elements such as cadmium and selenium. . To that end, these authors
This idea was applied to the preparation of semiconductor materials with an electronic structure showing a band of selected width. This idea is known to a person skilled in the art (JAvanVetchen et al, Revue de Physiqu.
e (Phys. Rev. B) 2, 2160-2167, 1970).

According to this idea, the forbidden band width of a semiconductor crystalline solid is determined on the one hand by the degree of coverage of the valence electron orbitals and on the other hand by the electronegativity difference between the cations and anions present in the solid. To be done. Therefore,
Furthermore, it is known that these amounts are directly related to the energy of the chemical bond between cation and anion.

The ionic conductivity of oxides used as solid electrolytes in fuel cells is primarily determined by the mobility of oxygen anions in the crystal lattice. This mobility is directly related to the energy of the chemical bond between these anions and the matrix and is quantified by the descriptor according to the invention. Therefore, the present invention is described by Professor JB Goodenough in "Conception de conducteurs ioniques oxyde.
s '' (`` Oxide-ion conductors by design '', Nature, 40
Vol. 4, April 20, 2000, pp. 821-822), by studying systematic cation substitution in oxides of the fluorite structure which show intracavity of oxygen, for example. It is applied to the search for new oxide families with high conductivity.

In exploration according to this principle, if the hypothetical structure to be examined is represented by the general formula AO, the descriptor D _AO for O at the standard crystallographic position and the standard position and adjacent intracavity (gap) Between D '
_The calculation according to the invention of the difference ΔD _AO between the descriptor D ′ _AO with respect to O at the intermediate position that maximizes _{AO, according} to the invention, is the desired use property, the mobility of element O in the crystalline matrix in the electrical region and Correlated measurements are provided. The most advantageous structure corresponds to the minimum value of ΔD _AO .

Other applications of the invention are possible in the search for substances with regard to optical, electronic or magnetic properties. The examples described are not limiting.

Therefore, in summary, the present invention relates to a method for estimating the use properties of a substance M _AB whose active element is AB,
The method comprises the following steps: (a) The value of the descriptor D _XY for the substance group M _{XY in} which the active element of the substance group Mxy is XY and the index R _XY for measuring the use properties of said substance is known. (B) Correlation R _XY =
the stage of charting or mathematical expression of f (D _XY ), (c)
Calculation stage of the descriptor D _{AB for} the substance M _AB ,
And (d) the value D _AB , the correlation R _XY = f (D
_XY ) or by using a mathematical expression of the correlation, a step of determining the index R _AB , which constitutes an estimate of the use properties for the substance M _AB is included.

In the method according to the invention, if the crystalline character of the substance is available, the descriptor D _XY and / or the descriptor D _AB may be calculated using method P1 which optionally comprises the following steps: That is, (a1) identification step of crystal characteristics of the substance XY (or AB) in the database of experimental crystallography, (a2)
A step of calculating the total energy E _XY (or E _AB ) per unit cell of the Brave crystal lattice of _XY (or _AB ),
(A3) Construction stage of the quasi-unit cell X (or A) obtained by removing B-type atoms from the optimum unit cell XY (or AB), (a4) per unit cell of the Brave crystal lattice of X (or A) the calculation step of the entire energy _{E X} (or _{E a),} (a5) the optimum unit cell XY (or AB) in the complement X (or a) quasi unit lattice obtained by removing the entire atoms belonging to Y (or B) construction stage, (a6) unit cell Y of the Brave crystal lattice of B
(Or B) calculation step of total energy _{E Y} (or _{E B)} per, (a7) optimal unit cell XY (or AB) in the Y (or B) present in the first coordination sphere of the atoms X (or A) A step of determining the number n of atoms, (a8)
Y (or B) by the optimum unit cell XY (or AB)
Step of determining the number of atoms b, and (a9) the following formula: D _{XY
= [E XY - (E X} + E Y)] / nb ( or _{D AB} =
[E _AB − (E _A + E _B )] / nb) calculation step of the descriptor D _XY (or D _AB ).

In the method according to the invention, further the descriptors D _XY and D _AB may be calculated using method P2, which optionally comprises the following steps: (a1).
Substance XY (or A by analogy with existing structure)
B) identification step of crystal characteristics, (a2) XY (or A
B) calculation step of total energy E _XY (or E _AB ) per unit cell of the Bravais crystal lattice, (a3) minimizing total energy and total energy E _XY (or E _AB ) depending on the calculation method adopted Step (a4) optimal unit cell XY, in which the value of the unit cell parameter of the structure that defines the optimum unit cell XY (or AB) of
(Or AB) a step of constructing a quasi-unit cell X (or A) obtained by removing a B-type atom, (a5)
Calculation step of total energy _{E X} (or _{E A)} per unit cell of the Bravais lattice of A, by removing the entire atoms belonging to the complement X (or A) of (a6) optimal unit cell XY (or AB) The step of constructing the obtained quasi-unit cell Y (or B), (a7) the step of calculating the total energy E _Y (or E _B ) per unit cell Y (or B) of the Brave crystal lattice of Y (or B), ( a8) a step of determining the number n of X (or A) atoms existing in the first coordination sphere of Y (or B) atoms in the optimum unit cell XY (or AB), (a9) optimum unit cell XY (or AB) ) number b determination stage per atom Y (or B), and (a10) the following _{equation: D XY = [E XY -} (E X +
E _Y )] / nb (or D _AB = [E _AB − (E _A + E
_B )] / nb) by applying the descriptor D _X
Calculation stage of _Y (or D _AB ).

It is also possible to use the method according to the invention by further calculating some descriptors using method P1 and other descriptors using method P2.

The present invention further relates to a method for determining the overall chemical affinity of an element or element B for matrix A, which method comprises the following steps: (a) identification of crystalline characteristics of substance AB, unit of AB Calculation of total energy per lattice, or iterative search step for values of parameters of optimal unit cell AB of total energy E _AB , (b) quasi-unit cell A by removing B-type atoms of optimal unit cell
, (C) a step of calculating the total energy E _A per unit cell of _A , (d) a step of constructing a quasi-unit cell B for removing all atoms belonging to the complement A in the optimal unit cell, (e) of B Total energy E _B per unit cell
(F) determining the number n of A atoms existing in the first coordination sphere of B atoms of the optimal unit cell, (g) determining the number b of B atoms of the optimal quasi-unit cell, and ( h)
It includes a calculation step of the descriptor D _AB according to the equation D _AB = [E _AB − (E _A + E _B )] / nb). If crystallographic data is available for material AB, step (a) involves identification of crystalline features of material AB and calculation of total energy per unit cell of AB. If these crystallographic data are not available, step (a)
It involves an iterative search for the values of the parameters of the optimum unit cell AB of the total energy E _AB . The corresponding crystallographic data is
Even if available, it is possible and sometimes preferred to carry out the iterative search.

In the process according to the invention, the substance AB can be, for example, a catalyst and the use characteristic can be, for example, the catalytic activity of the catalyst in a chemical reaction or its resistance to poisoning by impurities. A further use property may optionally be the containment power of the radioactive element in the solid inorganic matrix.

Many other use characteristics may be considered.
Thus, in the method according to the invention, the use properties are, for example, the corrosion resistance of a substance, the embrittlement of a substance by hydrogen, the adhesion to another substance, the mechanical action which adversely affects the integrity (intact state) (e.g. deformation, fracture or It may be selected from the group consisting of resistance of the material to abrasion, wetting by liquids or non-wetting. Further, the use property may be selected from the group consisting of optical properties, magnetic properties or electronic properties.

The invention therefore generally relates to the use of one of the methods according to the invention for the design of new substances. The use of new substances results in the formation or modification of at least one chemical bond or requires avoidance of the formation of said bond. Therefore, this new material most generally has improved use properties.

[0071]

Application of the Catalytic Material to the Search for Novel Compositions: In this first series of examples, where the relative activity of the catalyst with the active component being each of the pure transition metals is known, 2 The merits of the method according to the invention for identifying compositions of contact substances (catalysts) with active components which are alloys of two transition metals are explained. The catalytic reactions studied are ethylene hydrogenation, benzene hydrogenation, and carbon monoxide hydrogenation to methane.

[0072]: For Example 1 the calculation of the descriptor] metal carbide, by the method according to the invention, to calculate the descriptors D _MC metal-carbon bond for the entire transition elements from the crystalline characteristics of the corresponding carbides Will be possible. These features can be found in the database Crystme in the version sold by Materials Design sarl in version 1.1.1.4 of the Mede A interface.
Most of it was written down in "t" (note). Adopts BaTiO ₃ type perovskite M ₄ C structure, which corresponds to a compound for carbon insertion into the center of the cube in the face-centered cubic crystal lattice of metal, for carbides that have characteristics that were lacking in the base of Crystmet And by exploring, on a case-by-case basis, the optimal cubic unit cell, ie the edge value a of the cubic unit cell corresponding to the minimum value of the total electron energy. .

The calculation of the total electron energy is described in Materials Des in version 1.1.1.4 of the Mede A interface.
This was done by running the ElectrA program sold by ign sarl. The obtained results are shown in Table 1.

[0074]

[Table 1] Table 1: various calculations descriptor D _MC regarding transition metal (the unit cell, when the optimum unit cell according to the calculation method that is performed in ElectrA program, if indicated by the abbreviation Opt) In Table 1, the reference (see column )
Indicates the sequence number in the Crystmet base or the optimum unit cell parameter “a” generated by the optimization.

Example 2: Ethylene Hydrogenation The index R _MC used in this example is the relative intrinsic catalytic activity A for ethylene hydrogenation of a representative series of transition elements.
_r ^hydC2H4 . These activities were observed on metal films (O. Beeck, Modern. Phys., 17, 61, 1945 and Disc.
Faraday Soc., 8, 118, 1950) or supported on silica (GCA Shuit et al., Adv. Catalysis 10,242, 1958).
Years) by 273 K and 0.1 MPa by various authors
Measured in. Two authors found the same results, especially for the two embodiments of active metals.

Table 2 shows these available experimental results and combines them with the values of the descriptor D _MC , calculated using the method according to the invention, concluded from Table 1. The activity is related to the activity per atom of rhodium, the most active metal known for this reaction. ^{_Therefore, A r} _hydC2H4 ^(R
h) = 1.

[0077]

[Table 2] Table 2: Relative activity of transition metals for hydrogenation of ethylene
Degree and corresponding descriptor D_MCThe value of the. (Transition money
Genus is D_MCThe values are classified according to increasing values. ) FIG. 1 is a graphical representation of the results in Table 2. On this graph
And D on the abscissa _MCAnd A on the ordinate_r
^hydC2H4And plot. Coordinates (D_MC, A_r
^{h ydC2H4}Each point of (M)) has nothing to do with the embodiment.
The catalytic function of metal M
Characterizing. By connecting all of these points
And, very unexpectedly, the "volcanic" major
It is proven to get a curve.

[0078]: index _{R MC} used in Example 3 Hydrogenation of benzene This example is a relative intrinsic catalytic activity ^{_A r} _hydC6H6 regarding the hydrogenation of benzene. These activities have been measured at 373 K and 0.1 MPa by a variety of authors for a representative series of transition elements (eg French patent FR-2072586 and JFLe Page et al., "Catalyse de Contact").
(Contact Catalysis), English revised edition `` Applied Heterogen
eous Catalysis ”, p. 294, Technip Publishing, Paris, 1987).

Table 3 shows these available experimental results and combines them with the values of the descriptor D _MC , calculated using the method according to the invention, concluded from Table 1. The activity is related to the activity per atom of platinum, the most active metal known for this reaction. ^{_Therefore, A r} _hydC6H6 (Pt)
= 1.

[0080]

[Table 3] Table 3: values of descriptors D _MC corresponding and relative activity of the transition metal to the hydrogenation reaction of benzene. (Transition _metal. Are classified according to increasing value progressively the _{D MC)} in FIG. 2, to represent the results of Table 3 on the graph, and ^{_A r} _hydC6H6 in _{D MC} and ordinate abscissa Was displayed. Coordinate each point ^{_{(D MC, A r hydC6H6 (}} M)) relates to reactions considered independently of the embodiment, showing the intrinsic catalytic function of the metal M. By connecting all of these points, it is proved again that a "volcanic" main curve is obtained.

Example 4 Carbon Monoxide Hydrogenation The index R _MC used in this example is the relative intrinsic catalytic activity A _r for the hydrogenation reaction of carbon monoxide to methane.
It is ^hydCO . These activity is at 548K and 0.1MPa by various authors for a representative series of transition _elements, as measured with H 2 / CO mole ratio = 3. The values adopted are the criticality analysis published by MA Vannice (Catal Rev. Sci. Eng. 14, 2, 153-191,
1976).

Table 4 shows the results of these experiments and combines them with the values of the descriptor D _MC calculated according to the invention and concluded from Table 1. The activity is related to the activity per atom of ruthenium, the most active metal known for this reaction. _Therefore, it is ^{A r hydCO (Ru) = 1} .

[0083]

[Table 4] Table 4 : Relative activity of transition metals and corresponding descriptor D _MC values for carbon monoxide methanation reaction. (Transition metal _is classified for each value that increases progressively in the _{D MC.)} Figure ^3, _A ^r hydCO in _{D MC} and ordinate abscissa
5 is a graphical representation of the results of Table 4 with and. Coordinates (D
_MC, each point of ^{_A r} _hydCO (M)) relates to reactions considered independently of the embodiment represents the intrinsic catalytic function of the metal M. By connecting all of these points, it is proved again that a "volcanic" main curve is obtained.

Example 5 Comparison of Predicted Activity with Experimentally Measured Activity Performance levels (activity) of a series of two transition metal alloys for the reactions studied.
Was measured experimentally. In addition, the descriptor D _{MC of} each alloy was determined taking into account the composition and crystal structure adopted for the alloy. Table 5 shows the selected bimetallic pairs and the intermediate results needed for the calculation of the descriptor D _MC .

[0085]

[Table 5] Table 5 : Adopted metal pairs.

(Substances are classified by increasing values of the descriptor D _MC . Material data belonging to pure metals present in the metal pair are shown in italicized fine print. Other symbols are used. , The same as the notation specified in Table 1.) By recording the _DMC values obtained for the alloys on the abscissa axis of the graphs corresponding to the main curves shown in FIGS. The relative catalytic activity value, which is the expected activity value for the alloy for the corresponding reaction, can be read in the ordinate on the main curve.

Table 6 shows the value of the descriptor D _MC , the predicted activity and the experimentally measured activity for each alloy studied. This table shows that, according to the invention, on the one hand the error of the experimental measurement is taken into account and, on the other hand, the error of the approximation produced for the type of active bimetallic combination It is demonstrated that it is possible to obtain a good agreement between the physical activity.

[0088]

[Table 6] Table 6 : Comparison of the predictive catalytic activity according to the invention with the experimental activity for the metal pairs employed in Example 1.

The value of the descriptor D _MC is kJ mol ^−1.
Is. The reaction studied was the hydrogenation of benzene (HYD
B, references a and b) or xylene hydrogenation (HYDX, reference c), ethylene hydrogenation (HY).
DE, references d and e), and hydrogenation of carbon monoxide to methane (Meth. Ref f). Experimental or predictive activity was expressed as a relative value to that of pure metal. Predictive activity is obtained by linear interpolation on the main curves of Figures 1-3.

The effects observed experimentally by the method according to the invention are, for example: a significant promoting effect of iridium on osmium and rhenium in the hydrogenation of benzene, and of gold and palladium on platinum in the hydrogenation of monoaromatic compounds. Negative effect: providing a promoting effect of gold and silver on palladium in the hydrogenation of ethylene, a slight promoting effect of cobalt on iron in the methanation, and an almost absence of a significant effect of nickel on iron in the methanation Will be possible.

Therefore, the method according to the invention applies to any combination of elements in any number and proportion. The method also allows an evaluation for the purpose of a preliminary classification of the service properties (catalyst activity) of this combination for catalytic reactions with a predominantly determined main curve for the pure elements (activity / D _MC ).

Example 6 Application to Search for Storage Material of Radioactive Element Fluorapatite Ca ₁₀ (PO ₄ ) ₆ F
₂ is known as one of the most resistant substances to radiation-induced damage. As such, structural similarities of this mineral have been proposed for the storage of environmentally hazardous radioisotope isotopes. In addition, there are natural examples of such structural analogues, Oklo britholites, and outdated nuclear reactor sites (R. Bros et al., Radiochim.
cta 74, 277, 1996). The britholites have the general formula Ca
_10-Y E _Y (SiO ₄ ) _y (PO ₄ ) _{6- Y} (F, O
H) ₂ (wherein E is a rare earth or an actinide with a degree of oxidation of 3 and y is a real number 0 to 6) and has the same crystallographic structure derived from the structure of fluoroapatite, Especially with a hexagonal unit cell and a symmetry equal to or less than the symmetry of the space group (P63 / m). Cations occupy two sites that are not crystallographically equivalent.
The type of (1) is such that nine first adjacent oxygen O atoms are present in the first coordination sphere.
The type (2) has six first adjacent oxygens O in the first coordination sphere and the first adjacent F (fluorine) or O (oxygen) of the hydroxyl group OH. It has been shown that cations with larger ionic radius and weak charge have greater affinity for site (1), while cations with smaller ionic radius and stronger charge have greater affinity for site (2). Publicly known (J. Lin
Et al, Materials Chemistry and Physics, 38, 98-101.
P., 1994).

The method according to the invention was applied to estimate the descriptor D _AB in the case defined in Table 7.

[0094]

[Table 7] Table 7 : Definitions for the case of the study of Example 6 (explanation in parentheses indicates the localization of the element at site (1) or site (2)).

In the examples below, the calculated descriptors are noted by D _mU6 , for example, the descriptor of the energy of the U-matrix coupling in the case of 6.

Crystallographic features of the fluoroapatite and britholites structures were found in the ICSD data base (ICSD base reference 9444). The ab initio determination of the total energy per unit cell of complete or partial different structures present in the calculation of different descriptors is described by Molecular Simulatio
ns Inc., 6985 Scranton road, CA 92121-3752, USA
Obtained using the software "CASTEP" sold by. Not all unit cells were optimized,
On the other hand, the original unit cell of fluoroapatite was preserved. The various quantities present in the calculation of the descriptor according to the invention and obtained for this example are summarized in Table 8.

[0097]

[Table 8] Table 8 : Descriptor calculation according to the invention (numbering of these cases is shown in Table 7).

The solubility ratios are shown in Table 9. These ratios are estimated from the descriptors. The value of the descriptor is represented by the general formula derived from Boltzmann's law: RS [Ai / Bj] = Exp ((D _mAi −D
_It is shown in Table 8 by _mBj ) / kT). These 17
Returned to the reference temperature of 00K. This was the temperature at which the synthesis of britholites from constituent mineral sources was effective (L. Boyer, INP theory, Toulouse 1998 7
Month). In this general formula, k is the Boltzmann constant,
And 0.00831156 kJ · mol ⁻¹ · k ⁻¹ . Is equivalent to. T was the Kelvin absolute temperature.

D_mCa1And D_mSr3According to the comparison of
On the other hand, at the site (1) in fluoroapatite
It becomes possible to estimate the solubility ratio of Ca and Sr.
R, D _Ca2And D_Sr4By comparison, on the other hand
Ca and S at site (2) in fluoroapatite
It is possible to estimate the solubility ratio of r. By this
The radioactivity of strontium by substitution with calcium
Potential of fluoroapatite for storage of active isotopes
It becomes possible to estimate the force. A complementary comparison is D
_mCa2bisAnd D_mSr4bisBring You
That is, this comparison shows that
Estimate the overall ratio of Ca and Sr solubilities at any site
It becomes possible to do.

By comparing D _mI5 and D _mF6 ,
It is possible to estimate the solubility ratio of I and F in fluoroapatite. This makes it possible to estimate the potential of fluoroapatite for storage of radioactive isotopes of iodine by substitution with fluorine.

A comparison of D _mU7 and D _mCa8 makes it possible to estimate the solubility ratio of U and Ca at site (2) in blitrite. by this,
Substitution with calcium at site (2) makes it possible to estimate the potential of blitrite for storage of radioactive isotopes of uranium.

On the other hand, D_mCs9And D_mCa10,
And on the other hand D_mU11And D _mCa12To compare
Therefore, on the one hand, the site (1) in fluoroapatite
Of Cs and Ca on the other hand, and U on site (2) on the other hand.
And it becomes possible to estimate the solubility ratio of Ca
Allows for cesium and
Full for simultaneous storage of radioactive isotopes of ranium
It becomes possible to estimate the potential of oroapatite.

[0103]

[Table 9] Table 9 : Calculation of solubility ratio at 1700 K from descriptors according to the invention (numbering in combination with chemical elements is given in the case given in Table 7).

Table 9 shows the radioactive isotopes of the elements strontium, cesium and uranium on the one hand, by the ion substitution with the elemental calcium on the one hand, and with the elemental fluorine on the other hand, and by the method according to the invention, on the other hand the elemental iodine. We show that it is possible to classify different crystalline substances considered on the basis of their capacity to dissolve according to quantitative criteria. It is particularly demonstrated by the present invention that substitution with fluorine makes it possible to predict the very high affinity of fluoroapatite for iodine and its radioactive isotopes.

Fluorapatite also made possible the partial replacement of strontium with its radioactive isotope by calcium. However, as a result, strontium is dissolved in the fluoroapatite in an amount less than that in calcium. Obtained Sr3 / Ca1
The ratio is higher than the Sr4 / Ca2 ratio. Therefore, according to the method of the present invention, the crystallographic site (1) is favored over the site (2), consistent with the experiments of LIN et al. +
Ion radius of calcium for 2 (0.100 nm)
It has become possible to predict having a larger ionic radius (0.126 nm).

By the method according to the invention, brittleite
The very high solubility of uranium at the site (2) of
It becomes possible to measure. This is the Congo
Uranium in an obsolete reactor at the Oklo site in Go)
Confirmed by the presence of abundant Britolites. That
Instead, Cs on the fluoroapatite site (1)
⁺¹Ca by ion⁺²Aeon's site again (2)
U above⁺³Ca by ion⁺²Simultaneous ion replacement is
According to the method according to the invention, the descriptor D_{mCs 9}Negative of
(Table 8), which is an inconvenient reverse process.
Therefore, according to the present invention, for the storage of actinides,
A priori removal of fluoroapatite due to its nature
Is possible, and those skilled in the art
It will be possible to understand why even Britlite s prefer
It

[Brief description of drawings]

FIG. 1 is a graph of Table 2.

FIG. 2 is a graph of Table 3.

FIG. 3 is a graph of Table 4.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4G069 AA20 ED07                 5H026 AA06 EE12

Claims (7)

[Claims] 1. A novel substance M_ABFor design or choice
The active element of the substance is
By the method, which is AB by estimation (estimation) of quality use characteristics
Then, the next step: (a) the activity of the substance group Mxy
The element is XY and the usage characteristics of the substance are measured.
(Measure) index R_XYIs a known substance group M_XY
Descriptor D about_XYDeterminat
ion) stage, (b) descriptor D_XYAnd index R_XY
Correlation between (R_XY= F (D_XY) Decision stage,
(C) Material M_ABDescriptor D for_ABDecision
Stage, and (d) correlation between descriptor and index
R_XY= F (D_XY) To the index R_ABSubstances that undergo the decision of
M_ABThe use characteristic estimation stage
A method of using the descriptor D_XY
And descriptor D_ABBut the next step:
(1) Identification stage of crystal characteristics of substance XY (or AB)
Floor, (2) XY (or AB) Bravais
Calculation stage of total energy per unit cell of crystal lattice
Floor, (3) depending on the calculation method used, in some cases
To minimize total energy and total energy E
_XY(Or E_AB) Optimal unit cell XY (or A
B) Iterative search for values of unit cell parameters of the structure defining
Finding stage, (4) B of the optimum unit cell XY (or AB)
Quasi-unit cell X (or
Or the construction stage of A), (5) A single Brave crystal lattice of A
Total energy E per unit lattice_X(Or E _A) Total
Arithmetic step, (6) Within the optimum unit cell XY (or AB)
Remove all atoms belonging to complement X (or A)
Of the quasi-unit cell Y (or B) obtained by
Construction stage, (7) Y (or B) Brave crystal lattice
Total energy E per unit cell Y (or B)
_Y(Or E_B) Calculation step, (8) Optimal unit cell X
First coordination sphere of Y (or B) atom in Y (or AB)
Determining the number n of X (or A) atoms present in the body,
(9) Y per optimal unit cell XY (or AB)
(Or B) a step of determining the number b of atoms, and (10)
Descriptor D_XY= [E_XY-(E_X+ E_Y)] / N
b or D_{A B}= [E_AB-(E_A+ E_B)] / Nb
Novel substance M determined using a method that includes a calculation step
_ABMethods available for design or selection of. 2. The following steps: (a) identification of crystalline features of the substance AB, calculation of the total energy per unit cell of AB, or iterative search for the value of the parameter of the optimum unit cell AB of the total energy E _AB. , (B) Quasi-unit cell A by removing B-type atoms of the optimum unit cell
, (C) a step of calculating the total energy E _A per unit cell of _A , (d) a step of constructing a quasi-unit cell B for removing all atoms belonging to the complement A in the optimal unit cell, (e) of B Total energy E _B per unit cell
(F) determining the number n of atoms A existing in the first coordination sphere of the atom B of the optimum unit cell, (g) determining the number b of atom B of the optimum unit cell, and (h) ) Descriptor D _AB = [E _AB − (E _A + E _B )] / nb
Available methods for the design or selection of new substances that undergo an overall chemical affinity determination of element or element B to matrix A, including the calculation step of 3. The process according to claim 1, wherein the substance AB is a catalyst and the use characteristic is the catalytic activity of the catalyst in a chemical reaction or its resistance to poisoning by impurities. 4. The method according to claim 1, wherein the use property is the ability to hold the radioisotope in the solid inorganic matrix. 5. The use characteristic is the resistance of a substance to corrosion;
From the group consisting of embrittlement of a substance by hydrogen; adhesion to another substance; resistance of the substance to mechanical actions that adversely affect its integrity, such as deformation, fracture or wear; and wetting or non-wetting by liquids Selected, claim 1 or 2
The method described. 6. The use characteristic is selected from the group consisting of optical characteristic, magnetic characteristic and electronic characteristic.
The method described. 7. A method according to claims 1 to 6 in the selection or design of a novel substance with a use which results in the formation or modification of at least one chemical bond or which requires the avoidance of the formation of said bond. Use of the method according to any one of.