Patent Description:
Among halide salts, there are known organic halide salts, including halide salts of ammonia derivatives as well as inorganic halide salts, including metal-halide salts.

The methods for synthesis of the halide salts, both organic and inorganic, aiming at improving the purity of the obtained products and reducing the consumption of harmful or toxic reagents and solvents, are of constant development. Inter alia, the improved purity of the synthesized halide salts can reduce the post-synthesis treatment procedures, such as extraction, precipitation, filtration, charcoal treatment, distillation, etc..

The halide salts of high purity are used in various sectors of industry. For example, inorganic halide salts - such as lead bromide, as well as organic halide salts such as ammonium halide derivatives, e.g., methylammonium iodide (MAI), are used for synthesizing perovskites for photo-active materials used inter alia for the production of solar cells.

Moreover, various methods of synthesizing halide salts are known from the patent literature.

A publication o EP application <CIT> describes a method for synthesis of organic iodides of general formula RxNI; the method consists in synthesizing hydrogen iodide (HI) in situ by mixing molecular iodine with formic acid in the molar ratio of I<NUM> : COOH no less than <NUM>:<NUM>; next introducing, into the synthesizes HI, a compound being a donor of organic cation: RxN+, providing the molar ratio of RxN+:I<NUM> of no less than <NUM>:<NUM>, and next maintaining the reaction mixture at a temperature of not less than <NUM> to obtain the reaction product being the salt with the general formula RxNI. Synthesizing HI at the first step of the reaction product and maintaining certain ratios of the reactants prevent the formation of by-products being formates of respective organic cations ([RxN+] [HCOO-]), whose donors are added to the reaction mixture. This way the obtained product can be purified in a simple, low-cost manner.

A publication of European patent <CIT> describes a method for obtaining pure halide quaternary ammonium salt by reducing the amount of a protonic acid salt of a tertiary amine in the quaternary ammonium salt. The method consists in adding an oxide or hydroxide of metal to the quaternary ammonium salt contaminated with a protonic acid salt of a tertiary amine, and next removing the tertiary amine and water by distillation or heating while introducing nitrogen, argon or air, and metal salt produced by filtration or column purification.

In the processes for producing the halide salts belonging to the group of quaternary amine derivatives, typically, the synthesis involves reacting an acid with a respective halide. However, in the course of such synthesis, a part of tertiary amine of basis character (an organic basis), can left unreacted, and thereby can react with the acid to produce a protonic acid salt, permitting the acid salt to remain in the main product of quaternary ammonium salt as the contamination. Further, deacidification of the product solutions is necessary since complete removal of organic bases is possible only after said salts of the tertiary amine have been decomposed.

Further, preparing heavy metal halide salts may involve reacting two soluble metal salts, e.g. heavy metal nitrate with alkali metal halide, to form one soluble salt and one insoluble salt with may be removed by precipitation. For instance, lead nitrate solution and potassium iodide solution can react to produce solid lead iodide, leaving soluble potassium nitrate in the solution. However, the precipitate is typically contaminated with the soluble salt, thus, it may require further purification by washing and filtration procedures.

As follows from the above, many attempts have been taken to address the problem with the purity of the synthesized halide salts. However, despite the various approaches of modifying the synthesis pathway, the known methods do not provide the satisfactory effect of purity of the synthesized halide salts, due to incomplete conversion of the substrates, necessity of using certain substrates in excess, or the presence of by-products in the post-reaction mixture. Thereby, the application of labor-intensive and time-consuming post-treatment procedures, which generate additional costs and chemical wastes, are typically required to obtain the halide salts of required purity.

There is a need to provide a method for the synthesis of halide salts providing improved purity of the obtained products, thereby, limiting the required post-treating procedures.

In one aspect of the present disclosure, there is provided a method for synthesis of halide salts of the general formula (I):.

the method comprising reacting a first reactant being formate salt of the general formula (II):.

with a second reactant being a diatom halogen: X<NUM>.

Preferably, said diatom halogen X<NUM> is selected from Br<NUM> and I<NUM>.

Preferably, said cation (Zn+) is an inorganic cation of a metal selected from the group consisting of Cs+, Ag+, Pb<NUM>+, Sn<NUM>+, Bi<NUM>+, and Sn<NUM>+.

Preferably, said cation (Zn+) is Pb<NUM>+.

Alternatively preferably, said cation (Zn+) is an organic cation of the general formula (III), (IV), or (V):
<CHM>
wherein:.

Preferably, the organic substituent independently for each of R, R<NUM>, R<NUM>, R<NUM>, and R<NUM>, is selected from C<NUM>-C<NUM> alkyl, C<NUM> aryl or C<NUM> aryl, C<NUM>-<NUM> aralkyl, or heterocycle substituent.

Preferably, the organic substituent independently for each of R, R<NUM>, R<NUM>, R<NUM>, and R<NUM>, is selected from:.

Preferably, the organic substituent independently for each of R, R<NUM>, R<NUM>, R<NUM> and R<NUM>, is selected from:.

Preferably, said cation (Zn+) is the organic cation of the formula (VI), (VII), or (VIII):
<CHM>.

Preferably, the method comprises heating the reactants to the temperature of <NUM> to <NUM> until obtaining the halide salt.

Preferably, reacting of the reactants is carried out in the absence of a solvent.

Alternatively preferably, reacting of the reactants is carried out in the presence of a solvent.

Preferably, the solvent is selected from the group consisting of water, and acetone.

Preferably, the solvent is selected from the group consisting of water, alcohols, and acetonitriles.

Preferably, the method further comprises recrystallizing the obtained halide salt.

Further aspects and features of the present invention are described in the following description of the drawings.

Aspects and features of the present invention will become apparent by describing, in detail, exemplary embodiments of the present invention with reference to the attached drawings, in which:.

Reference will now be made to embodiments, examples of which are illustrated in the accompanying drawings. Aspects and features of the embodiments will be described with reference to the accompanying drawings. The present invention, however, may be embodied in various different forms and should not be construed as being limited only to the illustrated embodiments. Rather, these embodiments are provided as examples so that this disclosure will be thorough and complete, and will fully convey the aspects and features of the present invention to those skilled in the art. It shall be understood that not all of the features shown in the embodiments are essential and the scope of the protection is defined not by means of literally shown embodiments, but by the features provided in the claims.

The method for synthesis of halide salts according to the present disclosure involves reacting a formate salt of the general formula Zn+(HCOO)n with a diatom halogen: X<NUM>, preferably Br<NUM> or I<NUM> as schematically shown in <FIG>. The formate salt: Zn+(COOH-)n reduces the molecular (diatom) halide X<NUM> to ions: X- to form the halide salt of the general formula Znn+(X-)n, whereas the formate ions: HCOO- transform to gaseous and/or liquid byproducts comprising C, O and/or H. It is suspected that the reaction by products comprises CO and/or CO<NUM>, and H2O and/or H2, and more likely H<NUM>O. However, due to the volatile nature of the byproducts the chemical formulas of the byproducts are under investigation.

The reaction may occur with providing the stoichiometric ratio of the substrates. However, if one of the substrates, either the formate salt (Zn+(COOH-)n) or the halide (X<NUM>) is provided in excess, the reaction proceeds until total consumption of the other - deficient substrate. Thereby, no particular limitation for a ratio of these two substrates is required to carry out the synthesis of the halide salts, e.g. the halogen X<NUM> can be added in the amount ranging from <NUM>,<NUM> to <NUM>,<NUM> molar equivalents of the formate salt Zn+(HCOO)n.

To maintain a reasonable reaction time, preferably the reactants: Zn+(COOH-)n and X<NUM> are heated to the temperature of at least <NUM>, and preferably to the temperature of at least <NUM> or more, and more preferably the reactants are heated to a temperature between <NUM> and <NUM>, and preferably between <NUM> and <NUM>. For example, the mixture of Zn+(COOH-)n and X<NUM> can be heated to a temperature such as <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>° C, and most preferably <NUM>° C, to obtain the halide salt. During heating the mixture of reactants: Zn+(COOH-)n and X<NUM> can be agitated, e.g. stirred or shacked - to provide an increased level of molecules interactions. However, in the case of smaller amounts of the reactants, e.g., in the order of milligrams/milliliters, agitation is not necessarily required. Agitation of the reactants is preferably carried out throughout all the reaction duration. Agitating can be preferably performed from a few seconds to a few hours, and preferably from <NUM> minute to <NUM> hours, e.g., from <NUM> minutes to <NUM> hour.

Furthermore, the optimum synthesis conditions and times of the reaction may vary depending on the reactants used. Unless otherwise specified, solvents or solvent-free conditions, temperatures, pressures, and other reaction conditions may be readily selected by one of ordinary skill in the art to obtain optimum results for a particular reaction. Optionally, the reaction product may be purified by re-crystallization. For instance, the halide salt - being the reaction product can be obtained in pure form, in liquid or solid state - depending on its melting point, by simple removal of a reaction media such as solvent - if present, under reduced pressure and temperature below boiling or sublimation or decomposition point of the obtained halide salt. If the substrates are used in the stoichiometric ratio, both the substrates can be consumed in total, thereby, not contaminating the product, which enables one to achieved improved purity of the obtained halide salt.

In the course of the reaction, no acids such as hydrohalic acids (HX) are synthesized - the pH value of the reaction media, throughout the reaction of formate salt with the halide (X<NUM>), remains neutral, ca. pH = <NUM>. It is believed that the reaction of the formate salt with the halide: X<NUM> occurs by a free radical mechanism, and the halide: X<NUM> does not interact with protons H+ e.g. supplied with the solvent; it is further suspected that the reduction of halide: X<NUM> by formate salt constitutes a reaction that is privileged notwithstanding the solvent used, because the reaction leads to the halide salts in the solvent-free conditions as well. Is it further suspected that the solvent molecules, if present in the reaction medium, do not interact with the reactants forming intermediate products or transitional states (such as low-energy transitional states).

The method for synthesis according to the present disclosure allows obtaining halide salts according to the general formula (I):.

Preferably, the organic cation Zn+ of the halide salt is a derivative of amine, being either aliphatic amine, aromatic amine, aliphatic-aromatic amine, or aryloamine, including, where applicable, primary amine, secondary amine, tertiary amine; or derivative of imine such as e.g., formamidinium cation. The halide salt is obtained from the corresponding formate salt, comprising said organic cation Zn+, as shown schematically in <FIG>.

Preferably, the organic cation (Zn+) is represented by the general formula (III), (IV), or (V):
<CHM>
wherein.

As mentioned above R, R<NUM>, R<NUM>, R<NUM>, R<NUM> each independently represents hydrogen or an organic substituent, wherein at least one of R<NUM>, R<NUM>, R<NUM> is not hydrogen; the organic substituent, independently for each of R, R<NUM>, R<NUM>, R<NUM>, and R<NUM>, is preferably selected from:.

Non-limiting examples of the organic cation Zn+ used in the composition of the formic salt Zn+(HCOO-) to obtain the halide salt Zn+(X-), according to the present invention (<FIG>), include: ammonium cations, including alkylammonium cations, dialkylammonium cations, and trialkylammonium cations, amidinium cations, formamidinium cations; for instance Zn+ can denote: methylammonium CH<NUM>(H<NUM>)N+, ethylammonium CH<NUM>CH<NUM>(H<NUM>)N+, propylammonium C<NUM>H<NUM>(H<NUM>)N+, butylammonium C<NUM>H<NUM>(H<NUM>)N+, pentylammonium H<NUM>C<NUM>H<NUM>N+, hexylammonium H<NUM>C<NUM>H<NUM>N+, heptylammonium C<NUM>H<NUM>(H<NUM>)N+ or octylammonium C<NUM>H<NUM>(H<NUM>)N+ cation, formamidinium (H<NUM>N-HC=NH<NUM>)+, guanidinium (H<NUM>N)<NUM>-C=NH<NUM>)+ cation, or acetamidinium cation (H<NUM>N-H<NUM>CC=NH<NUM>)+.

Further, the non-limiting examples of the organic cation Zn+ include the cations represented by the following formula (VI), (VII), or (VIII):
<CHM>.

Thus, the developed method involving the reaction shown in <FIG> enables one to obtain halide salts, including bromide salts and iodide salts, depending on the halide used: Br<NUM>, I<NUM>, such as methylammonium halide, dimethylammonium halide, propylammonium halide, methylethylammonium halide, butylammonium halide, pentylammonium halide, hexylammonium halide, heptylammonium halide, octylammonium halide formamidinium halide, guanidinium halide, acetamidinium halide, benzylammonium halide, benzyl- methyl ammonium halide, phenethylammonium halide, N,N-dimethylpropane-<NUM>,<NUM>-diammonium halide, N,N-diethylethane-<NUM>,<NUM>-diammonium halide, iso-butylammonium halide, isopropylammonium halide, morpholinium halide, phenylammonium halide, dimethylammonium halide, trimethyl ammonium hailde, tertramethylammonium halide, di-isopropylammonium halide, hexane-<NUM>,<NUM>-diammonium halide, triewthyl ammonium halide, t-butylammonium halide, <NUM>-tertbutyl-phenylammonium halide, butane-<NUM>,<NUM>-diammonium halide, propane-<NUM>,<NUM>-diammonium halide, ethane-<NUM>,<NUM>-diammonium halide, diethylamine halide, N,N-Diethylethane-<NUM>,<NUM>-diammonium halide, cyclohexylethylammonium halide, <NUM>-(phenylene)di(etyylammonium) halide, <NUM>-t-butylbenzylammonium halide, <NUM>-thiophenmethylammonium halide, <NUM>-(<NUM>-Fluorophenyl)ethylammonium halide, <NUM>-Fluorobenzylammonium halide, <NUM>-aminovaleric acid halide, cyclohexanemethylammonium halide, <NUM>-(<NUM>-methoxyphenyl)ethylammonium halide, neopentylammonium halide, <NUM>,<NUM>-diazabicyclo[<NUM>. <NUM>]octane halide, N,N-dimethylethylenediamine dihalide, dibutylammonium halide, N,N-diethyl-<NUM>,<NUM>-propanediamine dihalide, piperazinium dihalide, pyrrolidinium halide, <NUM>,<NUM>-phenylenediammonium dihalide, <NUM>-azoniaspiro[<NUM>]nonane halide, cyclohexyl ammonium halide, <NUM>-(trifluoromethyl)benzylammonium halide, <NUM>,<NUM>,<NUM>-trimethylpentan-<NUM>-ammonium halide, N,N-dimethyl-<NUM>,<NUM>-propanediammmonium dihalide, dodecylammonium halide, dimethylammonium halide, dethylammonium halide, <NUM>-hexyl-<NUM>,<NUM>-diazabicyclo[<NUM>. <NUM>]octan-<NUM>-ium halide, morpholinium halide, n-octlyammonium halide, <NUM>-hydroxyphenethylammonium halide, <NUM>-chlorophenylammonium halide, <NUM>-methoxyphenethylammonium halide, <NUM>-furanmethylammonium halide, biphenylammonium halide, triphenylammonium halide, <NUM>-thiophenethylammonium halide, diethanolammonium halide, ethanolammonium halide, diphenylammonium halide2,<NUM>-dipmethylpropane-<NUM>,<NUM> diammonium halide, methoxyethylammonium halide, <NUM>-pyrrolidin-<NUM>-ium-<NUM>-ylethylammonium halide, quinuclidine-<NUM>-ium halide, piperidinium halide, tert-octylammonium halide, etc..

Preferably, the inorganic cation Zn+ of the halide salt constitutes a cation of metal Men+, such as Me+, Me<NUM>+, Me<NUM>+ and Me<NUM>+. Non-limiting examples of the inorganic cation Zn+ used as the component of the formic salt Zn+(HCOO-) - to obtain the halide salt Zn+(X-) according to the present invention (<FIG>), include the inorganic cations selected from the group consisting of: Cs+, Ag+, Pb<NUM>+, Sn<NUM>+, Bi<NUM>+, and Sn<NUM>+. More preferably the inorganic cation is Pb<NUM>+.

Thus, the developed method involving the reaction shown in <FIG> enables one to obtain halide salts, including bromide salts and iodide salts, depending on the halide used: Br<NUM>, I<NUM>, such as cesium halide (CsX), silver halide (AgX), lead (II) halide (PbX<NUM>), tin (II) halide (SnX<NUM>), bismuth (III) halide (BiX<NUM>) and tin (IV) halide (SnX<NUM>), including: CsI, CsBr, AgI, AgBr, PbBr<NUM>, PbI<NUM>, SnBr<NUM>, SnI<NUM>, BiBr<NUM>, BiI<NUM> SnBr<NUM>, SnI<NUM>.

The reaction, depending on the nature of the substrates, can be carried out in solvent-free conditions, for example for the respective formates (Zn+(HCOO-)n) being liquids in ambient conditions. <FIG> presents the embodiment of synthesis the halide salt, carried out in solvent-free conditions. The methylammonium formate - liquid at room temperature, reacts with iodine (I<NUM>) (solid), in the atmosphere of air or under inert gas (e.g. argon), under heating to a temperature of <NUM>-<NUM> and agitating, in solvent-free conditions. The obtained product can constitute pure methylammonium iodide crystals - in the case of using the stoichiometric ratio of the substrates - due to the total consumption of both the substrates, in solvent-free conditions, however, if the molar ratio of the substrates used is non-stoichiometric, e.g. <NUM>: <NUM> then the reaction can be carried out until total consumption of the deficient substrate. This embodiment thereby indicates that the solvent molecules are not necessarily needed to conduct the reaction. Similar to the above-described reaction of halide with methylammonium formate - the ethylammonium formate, propylammonium formate, butylammonium formate, or pentylammonium formate can be subjected to the reaction.

Alternatively, the reaction can be carried out in a solvent environment - for example for the respective formates (Zn+(HCOO-)n) being solids in ambient conditions, the solvent allows interacting one reactant (Zn+(HCOO-)n) with the other reactant (X<NUM>) - as the molcules of the substrates can move in the solvent. Also, it is a common practice to conduct a chemical reaction in a solvent medium, i. to improve agitating the mixture of reactants and provide better heat transfer within the reaction chamber. Thereby, the solvent aims at providing respective solubility of the reactants to improve the amounts of molecules interactions to better the product yield. The non-limiting examples of the solvents that can be used according to the present disclosure include polar solvents, non-polar solvents, being either protic or a-protic, organic or inorganic compounds. Further, a mixture of two or more solvent components can be used as the solvent. Non-limiting exemplary embodiments of the solvent, respectively inorganic and organic are water, methanol, ethanol, isopropanol, ethers, e.g. tetrahydrofuran or acetonitrile, or any mixture thereof, such as ethanol-water mixture, ethanol-ether mixture, isopropanol-water mixture, or acetonitrile-water mixture. alcoholic solvents can be used in pure form or in the form of their mixture with water, e.g. in form of water-alcohol azeotropes, such as a mixture of <NUM> wt% ethanol and <NUM>. 37wt% water. Also, substantially pure ethanol can be used as the organic polar solvent. The amount of solvent used is not particularly limited. For example, the amount of the solvent may range between <NUM> to <NUM> parts by volume (v/W), and preferably amount of the solvent may range between <NUM> to <NUM> parts by volume (v/W).

The purpose of solvent is to provide desired dissolution of at least one of the reactants, whereby the other reactant (undissolved) remains suspended in the reaction mixture, or to provide the desired dissolution of both the reactants. The use of the solvent thereby allows for desired agitation of the reactants to facilitate their chemical interaction.

The respective formate: (Zn+(HCOO-)n) for synthesis the corresponding halide salt, can be supplied to a reaction chamber in a form of commercially available products, such as, e.g. commercially available ammonium formate, formamidinium formate methylammonium formate. Alternatively, the respective formate: (Zn+(HCOO-)n) can be prepared in situ (in the reaction chamber), e.g., by using known methods. The exemplary scheme for the synthesis of halide salt comprising the organic cation according to the present disclosure, involving in situ preparation of the salt of formic acid is schematically shown in <FIG>. The formula RyNH<NUM>-y represents amine compound, which can be e.g., methylamine, which reacts with formic acid (Reaction <NUM>) leading to the respective salt formate: RyNH<NUM>-y+HCOO-, such as e.g. methylammonium formate. Following the synthesis of the formate salt, respective halide X<NUM> is added to the reaction chamber (Reaction <NUM>) resulting in halide salt. Reaction <NUM> can be carried out in water - as the solvent. Alternatively, other solvents can be used such as polar/non-polar organic solvent; or Reaction <NUM> can be carried out in solvent-free conditions.

Reaction <NUM> can be carried out in solvent-free conditions as well. If both reactions <NUM> and <NUM> are conducted as solvent-free, the obtained halide salt is already crystalline; this can be done preferably if one of the substrates is liquid in ambient conditions, or in the temperature of reaction. Furthermore, if the solvent is present, either in Reaction <NUM> or in Reaction <NUM>, or both reactions, the obtained halide salt, can be obtained by crystallizing the post-reaction mixture.

The orders in Reaction <NUM> have no particular limitation. For example, the primary/secondary/tertiary/quaternary amine can be reacted with formic acid in the organic or inorganic polar or non-polar solvent. The amount of the amine in Reaction <NUM> ranges from <NUM> molar equivalents to <NUM> molar equivalents with respect to the formic acid. Furthermore, the ammonium formate salts can be isolated in a liquid or solid state. The addition of formic acid to the amine is preferably performed at a temperature ranging between -<NUM> to <NUM>, in order to avoid condensation reaction with loss of water and amide formation. The said polar organic or inorganic solvent in Reaction <NUM> is preferably water, methanol, ethanol, isopropanol, tetrahydrofuran or acetonitrile, and more preferably water. The amount of the said organic solvent is not particularly limited, e.g., it can range between <NUM> to <NUM> parts by volume (v/W), such as <NUM> to <NUM> parts by volume.

Further, halogen (X<NUM>) in Reaction <NUM> can be added preferably in the amount ranging between <NUM> to <NUM>. 2molar equivalents of the formate salt, for example of <NUM> to <NUM> molar equivalents. The temperature in the reaction chamber during Reaction <NUM> is preferably maintained in the range of <NUM> to <NUM>° C, for example, the temperature of Reaction <NUM> can be maintained at <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, and more preferably <NUM>. During Reaction <NUM> the reactants are agitated. The duration of Reaction <NUM>, depending on the given formate salt, may range, e. from <NUM> minute to <NUM> hours, for example, <NUM> minutes to <NUM> hour. The obtained halide salt can be obtained in pure form in liquid or solid state by simple removal of the reaction media, such as solvent, under reduced pressure and temperature below boiling or sublimation or decomposition point of the obtained halide salt.

As a start, <NUM> of formic acid was added slowly under cooling (<NUM>) to <NUM> of methylamine (<NUM> wt% in H<NUM>O). The resulting solution was heated to <NUM> and <NUM> of iodine (I<NUM>) was added gradually. Afterward, the product was heated to <NUM> for the time necessary to remove the water. The formed solid was taken up with a <NUM> of hot ethanol and subsequently precipitated in an excess of cold diethyl ether. Afterward, crystals were collected by filtration; the obtained crystals were washed with diethyl ether, and dried in vacuum oven at <NUM>° C, to yield <NUM> of methylammonium iodide (<NUM>% yield).

<NUM>H NMR (<NUM>, DMSO-d6), d: <NUM>,<NUM> (s,<NUM>) <NUM> (s, <NUM>). <NUM>C NMR (<NUM>, DMSO-d6), d: <NUM> (ppm).

<FIG> present respective spectra of the obtained porduct.

<NUM> of methylammonium formate was heated at <NUM>. Under vigorous stirring, <NUM> of iodine (I<NUM>) was added gradually. The following precipitate was dissolved in small amounts of hot ethanol and subsequently precipitated in an excess of cold diethyl ether. Afterwards, the crystals were collected by filtration; the crystals were washed with diethyl ether and dried in vacuum oven at <NUM> to yield <NUM> of methylammonium iodide (<NUM>% yield).

<FIG>, presents the respective spectrum of the obtained product.

<NUM> of formic acid was added slowly under cooling (<NUM>) to <NUM> of methylamine (<NUM> wt% in H<NUM>O). The resulting solution was further cooled and <NUM> (<NUM>) of bromine (Br<NUM>) was added gradually. Afterwards the product was heated to <NUM> to remove the water. The formed solid was redissolved with a few <NUM> of hot ethanol and subsequently precipitated in an excess of cold diethyl ether. Afterward, crystals were collected by filtration; the crystals were washed with diethyl ether, and dried in vacuum oven at <NUM>° C, to yield <NUM> of methylammonium bromide (<NUM> % yield). <NUM>H NMR (<NUM>, DMSO-d6), (s, <NUM>). <NUM>C NMR (<NUM>, DMSO-d6) (ppm).

<FIG> presents IR spectrum of the obtained product (methylammonium bromide).

<NUM> of methylammonium formate was cooled at <NUM>. Under vigorous stirring, <NUM> of bromine (Br<NUM>) were slowly added. The following precipitate was dissolved in small amounts of hot ethanol and subsequently precipitated in an excess of cold diethyl ether. Afterwards, the crystals were collected by filtration; the crystals were washed with diethyl ether and dried in vacuum oven at <NUM> to yield <NUM> of methylammonium bromide (<NUM>% yield).

<CHM>
<NUM> of formic acid was added to <NUM> of formamidine acetate at room temperature. After the solid was completely dissolved, <NUM> of iodine (I<NUM>) was added gradually. Afterwards the product was heated to <NUM> to remove the water. The formed solid was redissolved with <NUM> of hot ethanol and subsequently precipitated in an excess of cold diethyl ether. Afterward, crystals were collected by filtration; the crystals were washed with diethyl ether, and dried in vacuum oven at <NUM>° C, to yield <NUM> of formamidinium iodide (<NUM> % yield).

<NUM>H NMR (<NUM>, DMSO-d6), d: ---- (d, <NUM>) ----(quint, <NUM>). <NUM>C NMR (<NUM>, DMSO-d6), d (ppm).

<FIG>, <FIG> present respective spectra of the obtained product (formamidinium iodide).

<CHM>
<NUM> of formamidine formate was heated at <NUM>. Under vigorous stirring, <NUM> of iodine (I<NUM>) was added gradually. The following precipitate was dissolved in small amounts of hot ethanol and subsequently precipitated in an excess of cold diethyl ether. Afterwards, the crystals were collected by filtration; the crystals were washed with diethyl ether and dried in vacuum oven at <NUM> to yield <NUM> of formamidinium iodide (<NUM>% yield).

<NUM> of tetramethylammonium hydroxide pentahydrate was weighed and dissolved in <NUM> of water. At <NUM>° C, <NUM> of formic acid was added into the solution first. Reaction was left at <NUM> for <NUM> hours. Afterward, <NUM> of iodine was added. The mixture was agitated for <NUM> hours at <NUM>° C. The reaction solution was cooled to <NUM>° C. Afterward, crystals as products were collected by filtration, washed with diethyl ether, and air-dried at <NUM>° C, to afforded <NUM> of title compound (<NUM>% yield).

<NUM>H NMR (<NUM>, DMSO-d6), d: <NUM> (s, <NUM>). <NUM>C NMR (<NUM>, D2O), d: <NUM>.

<FIG>, <FIG>, present respective spectra of the obtained porduct (tetramethylammonium iodide).

<CHM>
<NUM> of pyridine was weighed and mixed with <NUM> of water. At <NUM>° C, <NUM> of formic acid was added into the solution first. Reaction was left at <NUM> for <NUM> hours. Afterward, <NUM> of iodine was added. The mixture was agitated for <NUM> hours at <NUM>° C. The reaction solution was cooled to <NUM>° C. Afterward, <NUM> of ethanol was added, and agitating was performed for <NUM> minutes, then cold diethyl ether was added. Crystals as products were collected by filtration; the crystals were washed with diethyl ether, and air-dried at <NUM>° C, to afforded <NUM> of pyridinium iodide (<NUM>% yield).

<FIG>, <FIG> present respective spectra of the obtained product (pyridinium iodide).

<CHM>
<NUM> of imidazole was weighed and mixed with <NUM> of water. At <NUM>° C, <NUM> of formic acid was added into the solution first. Reaction was left at <NUM> for <NUM> hours. Afterward, <NUM> of iodine (I<NUM>) was added. The mixture was agitated for <NUM> hours at <NUM>° C. The reaction solution was cooled to <NUM>° C. Afterward, <NUM> of ethanol was added, and agitating was performed for <NUM> minutes, then cold diethyl ether was added. Crystals as products were collected by filtration; the crystals were washed with diethyl ether, and air-dried at <NUM>° C, to afforded <NUM> of imidazolium iodide (<NUM>% yield).

<FIG>, <FIG> present respective spectra of the obtained product (imidazolium iodide).

<CHM>
<NUM> of triethylamine was weighed and dissolved in <NUM> of water. At <NUM>° C, <NUM> of formic acid was added into the solution first. Reaction was left at <NUM> for <NUM> hours. Afterward, <NUM> of iodine (I<NUM>) was added. The mixture was agitated for <NUM> hours at <NUM>° C. The reaction solution was cooled to <NUM>° C. Afterward, <NUM> of ethanol was added and agitating was performed for <NUM> minutes. Crystals as products were collected by filtration; the crystals were washed with diethyl ether, and air-dried at <NUM>° C, to afforded <NUM> of triethylammonium iodide (<NUM>% yield).

<FIG>, <FIG> present respective spectra of the obtained product (triethylammonium iodide).

<CHM>
<NUM> of aniline was weighed and dissolved in <NUM> of water. At <NUM>° C, <NUM> of formic acid was added into the solution first. Reaction was left at <NUM> oC for <NUM> hours. Afterward, <NUM> of iodine (I<NUM>) was added. The mixture was agitated for <NUM> hours at <NUM>° C. The reaction solution was cooled to <NUM>° C. Afterward, <NUM> of ethanol was added and agitating was performed for <NUM> minutes, then cold diethyl ether was added. Crystals as products were collected by filtration; the crystals were washed with diethyl ether, and air-dried at <NUM>° C, to afforded <NUM> of aniline hydroiodide (<NUM>% yield).

<FIG> presents respective spectrum of the obtained product (aniline hydroiodide).

<CHM>
<NUM> of benzylamine was weighted and dissolved in <NUM> of water. At <NUM>° C, <NUM> of formic acid was added into the solution first. Reaction was left at <NUM> for <NUM> hours. Afterward, <NUM> of iodine (I<NUM>) was added. The mixture was agitated for <NUM> hours at <NUM>° C. The reaction solution was cooled to <NUM>° C. Afterward, <NUM> of ethanol was added and agitating was performed for <NUM> minutes, then cold diethyl ether was added. Crystals as products were collected by filtration, washed with diethyl ether, and air-dried at <NUM>° C, to afforded <NUM> of benzylamine hydroiodide (<NUM>% yield).

<FIG>, <FIG> present respective spectra of the obtained product (benzylamine hydroiodide ).

<CHM>
<NUM> of glycine was weighed and dissolved in <NUM> of water. At <NUM>° C, <NUM> of formic acid was added into the solution first. Then reaction was left at <NUM> for <NUM> hours. Afterward, <NUM> of iodine (I<NUM>) was added. The mixture was agitated for <NUM> hours at <NUM>° C. The reaction solution was cooled to <NUM>° C. Afterward, <NUM> of ethanol was added and agitating was performed for <NUM> minutes, then cold diethyl ether was added. Crystals as products were collected by filtration; the crystals were washed with diethyl ether, and air-dried at <NUM>° C, to afforded <NUM> of glycine hydroiodide (<NUM>% yield).

<FIG>, <FIG> present respective spectra of the obtained product (glycine hydroiodide).

<CHM>
<NUM> of β-alanine was weighed and dissolved in <NUM> of water. At <NUM>° C, <NUM> of formic acid was added into the solution first. Reaction was left at <NUM> for <NUM> hours. Afterward, <NUM> of iodine was added. The mixture was agitated for <NUM> hours at <NUM>. The reaction solution was cooled to <NUM>° C. Afterward, <NUM> of ethanol was added, and agitating was performed for <NUM> minutes, then cold diethyl ether was added. Crystals as products were collected by filtration, washed with diethyl ether, and air-dried at <NUM>° C, to afford <NUM> of <NUM>-aminopropionic acid hydroiodide (<NUM>% yield).

<FIG>, <FIG> present respective spectra of the obtained product (<NUM>-aminopropionic acid hydroiodide).

<CHM>
<NUM> of sarcosine was weighed and dissolved in <NUM> of water. At <NUM>, <NUM> of formic acid was added into the solution first. Reaction was left at <NUM> for <NUM> hours. Afterward, <NUM> of iodine (I<NUM>) was added. The mixture was agitated for <NUM> hours at <NUM>. The reaction solution was cooled to <NUM>. Afterward, <NUM> of ethanol was added, and agitating was performed for <NUM> minutes, then cold diethyl ether was added. Crystals as products were collected by filtration, washed with diethyl ether, and air-dried at <NUM>° C, to afford <NUM> of N-methylglycine hydroiodide (<NUM>% yield).

<FIG>, <FIG> present respective spectra of the obtained product (N-methylglycine hydroiodide).

<NUM> lead (II) acetate were dissolved in <NUM> of water. Subsequently, <NUM> of formic acid were added, resulting in a colorless precipitate. The intermediate product was filtrated and washed with cold water. Subsequently, the wet intermediate product was dissolved in <NUM> of hot water. <NUM> of acetone and <NUM> of iodine (I<NUM>) were added gradually to the solution under vigorous stirring. The mixture was further agitated for <NUM> minutes and crystallization of the lead (II) iodide (<NUM>, <NUM>% yield) was performed in the refrigerator over night.

<FIG> presents the respective X-ray diffraction pattern of the obtained product (lead (II) iodide).

<NUM> lead(II) acetate were dissolved in <NUM> of water. Subsequently, <NUM> of formic acid were added, resulting in a colorless precipitate. The intermediate product was filtrated and washed with cold water. Subsequently, the wet intermediate product was dissolved in <NUM> of hot water. <NUM> of acetone and <NUM> of bromine were slowly added to the solution under vigorous stirring. The mixture was further agitated for <NUM> minutes and crystallization of the colorless lead (II) bromide (<NUM>, <NUM>% yield) was performed in the refrigerator over night.

Claim 1:
A method for synthesis of halide salts of the general formula (I):

        Zn+X-n     Formula I

wherein:
X- represents a halogen anion, and
Zn+ represents a cation having a valency n,
the method comprising reacting a first reactant being formate salt of the general formula (II):

        Zn+(COOH-)n     Formula II

with a second reactant being a diatom halogen: X<NUM>.