WO2010000881A1

WO2010000881A1 - New gels resulting from the reaction of solutions formed by a source of aluminium having hydroxyl groups and hexamethylenetetramine with one or more additives

Info

Publication number: WO2010000881A1
Application number: PCT/ES2008/000464
Authority: WO
Inventors: Jesús María TANCO SALAS
Original assignee: Tanco Salas Jesus Maria
Priority date: 2008-06-30
Filing date: 2008-06-30
Publication date: 2010-01-07

Abstract

It is known that a dihydrated aluminium halohydroxide, triethylaluminium, etc, preferentially dihydrated aluminium chlorohydroxide, oligomerises in the presence of water if to such mixture is added hexamethylenetetramine at a temperature between 25 and 50°C and pH exceeding 2.5, preferentially 4, polymerisation is notably speeded up, which is attributable to a catalytic effect of the amine, hexamethylenetetramine being a cyclic polyamine having four active nitrogens in terms of possessing pairs of free electrons, it may exercise the role of crosslinking agent of polymeric chains of the aluminium complex giving rise to formation of a three-dimensional network wherein polymer chains mutually connect by bonds with molecules of hexamethylenetetramine, such three-dimensional character arising from the fact that hexamethylenetetramine may link up to four polymeric chains through the four active centres it possesses without important steric effects occurring consequent upon the volume of the chains, said active centres being nitrogens having free electron pairs and which may form coordinate or dative bonds, the result obtained being a transparent gel of variable fluidity depending on the proportion of hexamethylenetetramine and water, having diverse applications as vehicle in components such as: air fresheners, insecticides, fungicides, disinfectants, ions and/or similar.

Description

NEW GELS RESULTING FROM THE REACTION OF SOLUTIONS FORMED BY AN ALUMINUM SOURCE WITH HYDROXYL AND HEXAMETILENTETRAMINE GROUPS WITH ONE OR MORE

ADDITIVES

D E S C R I P C I Ó N

OBJECT OF THE INVENTION

The present invention refers to a new crosslinked compound with gel properties with controllable fluidity and physicochemical properties that allow its application as a vehicle in various applications, said compound is obtained by the reaction of urotropin or hematelylenetetramine with an aluminum source that has radicals hydroxyl in aqueous medium and optionally one or more additives, with pH and temperature controlled

BACKGROUND OF THE INVENTION

In an aqueous solution at room temperature an aluminum source that can preferably be slowly dihydrated aluminum chlorohydroxide slowly oligomerizes forming macromolecules of varying size according to the conditions that respond to the next elementary cell repeated n times

In these complex polymer chains, aluminum is hexa-coordinated, with the ligands being hydroxyl groups, anions or water molecules. In the complex each aluminum cation maintains three net ionic bonds and three coordinated bonds.

In the presence of hexamethylenetetramine, the process is modified depending on the source of precursor aluminum, as can be seen in US Pat. No. 3,132,141 where the complex formed is of the organ-metallic type, since aluminum is directly attached to the carbon atom. , forming chemically stable complexes, where no catalytic polymerization is observed, nor hydroxyl radical binding, the complexes have the following structure: (CH ₂ ) ₆ N ₄ . a Al R _n X (3- _n > where: a is a number between 1 and 3; R is an alkyl radical containing at least 7 carbon atoms; X is a halogen and n is a number between 1 and 3.

The invention also reveals a process for preparing these complexes by reaction of hexamethylenetetramine and an alkyl aluminum complex or a halogenated derivative of an alkyl and aluminum complex at room temperature.

The US patent document 3,496,111 deals with the formation of a typical alkyl aluminum complex, by means of the reaction of triethyl aluminum and a sufficient amount of hexamethylenetetramine, where there is no intervention of hydroxyl radicals, the result is a complex of alkyl-amino and aluminum this in turn is treated with a chemical-luminescent agent, as the starting point of the reaction can be seen is a known organ-metal complex and the intermediate complex formed is also a metal organ complex.

In the present invention, when treating the complex of halide and basic aluminum dihydrite with a sufficient amount of hexamethylenetetramine in the presence of water, a polymer not described in the cited patents is obtained, since it is originated by means of a basic catalysis this polymer is of a structure different from those hitherto known which presents numerous applications

DESCRIPTION OF THE INVENTION

As we know an aluminum source such as an aluminum halohydroxide dihydrate, triethyl aluminum, etc. although preferably it can be the aluminum chlorohydroxide dihydrate in the presence of oligomeric water producing molecules of the type:

When hexamethylenetetramine is added at a temperature between 25-5O ⁰ C, the polymerization is greatly accelerated, which can be attributed to A catalytic effect of the amine, as we know well, hexamethylenetetramine is a cyclic polyamine with four active nitrogens as regards the possession of free electron pairs, this can play the role of a crosslinking agent of the polymer chains of the aluminum complex Io which gives rise to the formation of a three-dimensional network in which the polymer chains connect to each other by means of unions with hexamethylenetetramine molecules, the three-dimensional character comes from the fact that hexamethylenetetramine can bind up to four polymer chains through the four active centers it possesses without important steric effects occur due to the volume of the chains, the active centers are: nitrogens that have free electronic pairs and that can form coordinated or dative bonds, the result obtained is a transparent gel of variable fluidity depending on the proportion of hexamethylenetetramine and water that responds structurally to Ia distribution that is reflected in the scheme of the figure

1 where the polymer chains of chlorine aluminum hydroxide are represented by lines connected by hexamethylenetetramine molecules.

This complex macro structure has cavities in its three-dimensional network that house water molecules and possibly other polar molecules where appropriate, which is compatible with its geliform nature, it is observed that the viscosity of the gel increases with time, which would be explained by Increase the number of unions for the nitrogens still free and thereby increase the degree of cross-linking, in any case we could talk in this case of a reversible cross-linking, since the unions in the chains are made through coordinated or dative bonds that can be broken to be replaced by other non-versatile ligands (such as water) in equilibrium situations that control the stability constants of the different complexes.

This result can also be obtained using an aluminum source such as triethylaluminum but with the addition of an additive that can maintain the pH at values higher than 2.5 units, this additive can be a buffer solution or component that makes the medium more basic always and when it does not interfere with the main reaction.

DESCRIPTION OF THE FIGURES

Fig 1- Shows the mass spectrum of aluminum chlorohydroxide

Fig 2- Shows the mass spectrum of the HMTA

Fig 3- Shows the mass spectrum of the new polyhexamethylene tetraminyl-polypentahydroxy-aluminum chloride gel Fig 4-Shows the thermogram heat flux temperature of Aluminum Chlorohydroxide

Fig 5-Shows the thermogram heat flow temperature of the HMTA Fig 6-Shows the thermogram heat flow temperature of the dried gel Fig 7-Shows the HPLC of Aluminum Chlorohydroxide for a water content of 93/7 Fig 8- Shows the HPLC of the gel for a water content of 90/10

Fig 9- Shows the HPLC of the HMTA for a water content of 90/10 Fig 10- Shows the HPLC of the gel for a water content of 93/7 Fig 11- Shows the HPLC of the HMTA for a water content of 93 / 7 Fig 12- Shows the HPLC of the gel for a water content of 95/5 Fig 13- Shows the HPLC of the HMTA for a water content of 95/5

Fig 14- Shows the HPLC of the gel for a water content of 97/3 Fig 15- Shows the HPLC of the HMTA for a water content of 97/3 Fig 16- Shows the HPLC of the gel for a water content of 100 / 0 Fig17-Shows the structure of the AI-HMTA complex for [AI ₂ (OH) ₅ CI] Io (C ₆ H ₁₂ N ₄ ) (H ₂ O) ₁₇

PREFERRED EMBODIMENT OF THE INVENTION Next, the preparation of a standard sample is described as a preferred but non-limiting embodiment using stoichiometrically acceptable proportions in order to avoid other products that interfere with the final analysis, approximately 30 grams of aluminum chlorohydroxide dihydrate (11092 Acofarma) were weighed which were Dissolve with stirring at room temperature in 30 ml of demonized water, when the solution is complete, slowly add and with stirring another solution that is prepared by dissolving 2 grams of hexamethylenetetramine (Doesler) in sufficient amount of water and let it rest until it gels The time it takes to gel depends on the temperature, at higher temperatures the ambient temperature increases the gelation rate up to 4 times faster but problems of dehydration of the gel can occur due to evaporation of the solvent, so a temperature range between 25-50 ⁰ C, another form of a To activate the reaction speed consists in using a magnetic stirrer which would prevent the dehydration of the gel in some way, this fact is consistent with the proposed structure, since the agitation favors the molecular mobility and therefore the establishment of HMTA chain bonds by The increase in the number of collisions, when drying the product obtained by means of high vacuum for about 48 hours until a constant weight is obtained, results in a transparent crystalline solid by micro analysis, its percentage composition without apparent deviation results in: C = 3.28%, H = 4.38% and N = 2.55% Which allows us to propose the following as an empirical formula:

([AI ₂ (OH) ₅ CI] ₁₀ (C ₆ H ₁₂ N ₄ ) (H ₂ O) _1T ) _n

Which has a theoretical composition: C = 3.26%, H = 4.43% and N = 2.53%

Which is quite close to the experimental result. A formula developed for n = 1 is:

However, as in the same chain there may be several coordinated AI - «- N connections, this may result in the molecule having a variable number of C ₆ Hi ₂ N _{4 groups} and depending on the proportions varying amounts of AI ₂ (OH) ₅ CI and H ₂ O, so a general molecular formula would be: {[AI ₂ (OH) 5X] a (C6Hi2N ₄ ) b (H2θ) c} n

At the same time physicochemical tests were performed as comparative sublimity, comparative solubility, hydration water and other tests

Sublimity compared

The sublimated hexamethylenetetramine between 160 and 260 ⁰ C according to the experimental conditions, this sublimation was observed in a Mettler FP 82 + FP 80 melting point determination systems, with microscope, video camera and a monitor for observation in real time, these observations were made using a temperature variation of 10 ° c / min. where the sublimation can be seen in a superior glass covering the oven at 176 ⁰ C, under the same conditions the dried aluminum-HMTA chlorohydroxide gel does not produce any sublimation and only decomposition is observed above 300 ⁰ C, which demonstrates a chemical fixation of the HMTA that in its pure state would reflect a normal sublimity. Solubility differences

HMTA is very soluble in chloroform at room temperature, 1 gram of HMTA dissolves easily in 10 ml of chloroform, however chloroform solubility tests indicate that the gel formed is not soluble in chloroform even partially (insoluble residue) , 5 grams of gel were placed in 100 ml of chloroform at room temperature, using a magnetic stirrer for 24 hours, the solid was filtered and the solvent was removed by vacuum rotation, the solvent being evaporated left no solid residue. which indicates that there has been no extraction of the HMTA present which discards a physical mixture and confirms an HMTA fixed by complexation that is not displaced by the chloroform

When the experience is carried out with a wet gel, freshly prepared, to which 200 ml is added. of water and extracted with 100 ml of chloroform with stirring for 24 hours, an HMTA residue can be identified by infrared spectroscopy by removing the chloroform used in the extraction under vacuum. In these dilution conditions the complex is broken, the HTMA is released that passes partly to the organic phase although some amount remains in the aqueous phase in which it is also soluble, since the pH is approximately 5, when the alkaline is Ia solution with NaOH and diluted to avoid precipitation in this medium, the extraction of HMTA is produced in greater quantity.

Crystallization water and coordination water:

The proportion of water that the gel admits is variable thanks to the three-dimensional structure that allows water molecules to be housed in a considerable amount in its reticule before being destroyed by dissolution and loss of coordination. In the water contained in a sample must distinguish the content of the set of molecules used in coordination with aluminum, strongly fixed and those of hydration strongly housed in the interstices of the reticulum.

In another preferred embodiment of the invention, a sample of the aluminum chlorohydroxide-HMTA gel is prepared under the specified conditions

Aluminum chlorohydroxide solvent .... 30 grams Reagent aluminum chlorohydroxide hydration water ... 5.1 grams HMTA solvent 8.0 grams

Total .... 41 grams

What in a total sample weight of 70 grams implies a water content in the gel of 61.6%, when this gel is dried to a solid of constant weight in high vacuum for 48 hours and in the presence of phosphorus pentoxide as desiccant agent, a material that has lost 56% of its weight in the form of non-fixed water is obtained, retaining 4.7% of the original water sample weight as a ligand, which over solid waste weight after drying and disposal of unbound water implies 40.8%, which roughly matches the empirical formula proposed with the dried aluminum-HMTA chlorohydroxide gel (theoretical 13.9%), the difference with respect to the theoretical one may be due to the fact that in the process so In the energy of desiccation, some loss of water will occur due to the formation of Al-O-Al junctions from two AI-OH hydroxyl of different chains nearby, which is consistent with the properties of this solid. The exhaustively dried gel, after being exposed to a moderately humid environment, recovers hydration water without being subsequently hygroscopic.

In order to support the proposed structure, an experience of preparation of the equivalent product was designed but using another amine, for that it was considered to have similar physicochemical properties, the chosen amine is triethylenediamine (1, 4 diazabicyclo [2.2.2] octane) . The result experimentally obtained consists of a product less viscous than that obtained with the same molar ratio of HMTA, said product does not gel, which is compatible with the possibility of crosslinking by exclusive binding of two chains by having only two nitrogen with the ability to coordination.

In order to verify the degree of cross-linking proposed in a qualitative and quantitative way, some tests were prepared in which the proportion of HMTA present was varied. Since the proportions of the different components can be of great variability, the content of water around 60% to facilitate solubility in the gel sample preparation tasks, completing the value up to approximately 100 with the sum of the percentages of aluminum chlorohydroxide and HMTA. The sample sample contains 2.85% HMTA.

It has been determined that percentages of HMTA below 2% do not allow adequate gelation, while values above approximately 4.5% lead to excessively rapid gelation that has a greater solidification character and produces solid vitreous-looking materials, values of 9% result in solids directly with solubility difficulties for their preparation.

All samples were prepared and allowed to gel at rest at room temperature, consequently it follows that the interval between 2 and 4% of HMTA as a crosslinker is the one that generates viscous gels, of good characteristics for handling and producing the gelation in a reasonable time, showing the proportion of HMTA as an important variable to control the degree of crosslinking of these products, this is the expected behavior according to the proposed structure.

Mass spectrometry

Mass spectra were performed on an ionization spectrometer. Due to electronic impact, a comparative study was carried out between the reagents separately and the product, obtaining the following results:

M1: Aluminum chlorohydroxide due to its inorganic nature does not volatilize and does not give useful spectrum

M2: The HMTA is abundantly volatilized and fragmented rapidly, where a marked molecular peak is observed in 140 more units / load M3: The gel behaves practically like M1 without volatilization and does not give useful spectrum. Therefore, in view of the Results can be assured that there is a consistent union between the HMTA and the complex polymer, since if what existed was a physical mixture, a volatile product with a peak of 140 mass / load units would be present and the rest would not volatilize.

These results are consistent with those obtained using differential scanning calorimetry, where the heat flow temperature thermograms of the three samples were recorded on a calorimeter, obtaining for the dried gel (M3) a thermogram different from that recorded by aluminum chlorohydroxide (M1 ) and the HMTA (2), which demonstrates that a physical mixture of the components is not obtained, since otherwise the thermogram would give us the sum of its components, in the gel (M3) a melting peak is observed not present in the sample of aluminum chlorohydroxide (M1) and at a different melting temperature of the HMTA, a melting process of a material with better packing is also observed on the gel thermogram, which demonstrates the cross-linking role of the HMTA.

High resolution chromatography (HPLC) tests were also performed, mixtures of methanol and water 90/10 and 100/0 (V / V) were used as more suitable mobile phases, the water was adjusted to pH = 8 with triethylamine, To avoid ionization of the HMTA by protonation of its hydrogens, the samples were prepared by dissolving the complex aluminum chlorohydroxide-HMTA gel previously dried in the corresponding medium used as a mobile phase in each experience. For the higher contents of water used (90/10, 93/7 and 95/5), the chromatograms corresponding to the gel samples show the characteristic peak of the HMTA, which was easily identified by comparison of the chromatographic pattern obtained from that pure substance under the same chromatographic conditions. The retention time of the HMTA in the three mobile phases is in a range between 2.38 and 2.4 minutes, likewise the aluminum chlorohydroxide is observed as a set of wide peaks attributable to the stable oligomers and polymers of various sizes and complexing of this compound in solution, from this observation it is concluded that these aqueous conditions the complex is destroyed and leaves the crosslinking amine free and chlorohydroxide and HMTA run through the independent bed.

The dried gel is poorly soluble in methanol and when using phase like 97/3 and 100/0 the complex is not destroyed and therefore the characteristic peak of the HMTA does not appear

The invention provides a vehicle of substances of interest that can be insecticides, odor neutralizers or air fresheners, disinfectants, fungicides, ions, etc., whose composition comprises the gel of the Aluminum complex and HMTA disclosed above, where optionally one or more can be added additives, these additives include the solvents where the components that are the starting principle for the formation of the complex, the pH correctors and the components that allow the formation and / or stability of the AI-HMTA complex, the solvents in are dissolved As the aluminum components that give rise to the complex are dissolved include water, alcohols or a mixture of both, the source of aluminum as well as the HMTA must be water soluble, however as in the substances of interest there are usually insoluble or little components soluble in water, but if soluble in alcohol, the vehicle of Ia The invention may contain, in addition to water, said alcohol optionally trapped by the AI-HMTA complex.

The pH correctors can be substances or buffer solutions that allow the pH of the medium to exceed 2.5 pH units, since tests have shown that at pH below this amount the complex becomes unstable and is destroyed by decomposition of Ia HMTA, it has been shown that at pH higher or preferably above 4.5 pH units the complex is very stable, the use of the pH corrector depends on the source of aluminum used, since for example with Chlorohydroxide of Aluminum is not necessary to use, because the medium has a pH higher than 4.5 pH units, there are cases where the starting point may be other components that, when dissolved in the medium, result in pH lower than 2.5 Since it is necessary to add a basic component that does not react with the previous ones and allows the pH of the medium to be raised, the substances that favor the stability of the complex can be alcohols and amphoteric metal acetates.

The starting point for the formation of the complex is preferably hydrated aluminum chlorohydroxide, although other sources of aluminum from the group of dihydrated aluminum halohydroxides, mixtures of aluminum sulfate and aluminum hydrochloride can be used, with very good results. pH higher than 4 units and with aluminum sulfate, under the same pH conditions (mixtures of aluminum sulfate and a small amount of aluminum hydroxide) as well as triethyl aluminum and a hydroxyl donor, the solvents that can be used are Open chain monoalcohols, open chain diols, propylene glycol, etc.

The pH should be greater than 2.5 pH units preferably greater than 4 and the optimum temperature should be between 25 ⁰ C and 5 ^{0 0} C

Claims

R E I V I N D I C A C I O N E S

1 .- New gel resulting from the reaction of an aluminum source and hexamethylenetetramine with one or more additives is characterized by general molecular formula Ia below:

([AI ₂ (OH) ₅ X] ₃ (C ₆ H ₁₂ N ₄ ) ^ H ₂ O) J _n

Where a, b, c and n are integers

X is a monovalent anion

2 ^a New gel resulting from the reaction of a solution of a source of aluminum and hexamethylenetetramine with one or more additives according to claim 1 characterized in that the structure is:

When the values a = 10, b = 1, c = 17 and n = 1 are taken, X = Cl being

3 ^a - New gel resulting from the reaction of an aluminum source and hexamethylenetetramine with one or more additives according to claim 1 wherein the aluminum source is comprised of: dihydrated aluminum chlorohydroxide, triethyl aluminum, aluminum acetate, aluminum sulfate, aluminum hydroxide or a mixture of them 4 .- New gel resulting from the reaction of an aluminum source and hexamethylenetetramine with one or more additives according to claim 1, characterized in that the reaction is carried out at a temperature of between 25 and 50 ⁰ C

5 ^a - New gel resulting from the reaction of a solution of a source of aluminum and hexamethylenetetramine with one or more additives according to claim 1, characterized in that the gel is formed in medium with pH greater than 2.5 units preferably 4 ,5 units.

6 ^a - New gel resulting from the reaction of a solution of a source of aluminum and hexamethylenetetramine with one or more additives according to claim 1, wherein the additives comprise alcohols, salts of amphoteric metals or mixtures thereof.

7 ^a - New gel resulting from the reaction of a solution of an aluminum source and hexamethylenetetramine with one or more additives according to claim 1, wherein the solvent for the aluminum source comprises water, alcohols, or mixtures thereof.

8 ^a - Vehicle of substances of interest using the gel of claim 1, wherein the substances of interest are selected from air fresheners, insecticides, fungicides, disinfectants, ions and / or the like.

9 ^a - Vehicle of substances of interest according to claim 7, characterized in that the aluminum complex and hexamethylene tetramine present is in a concentration between 0.8 and 90% with respect to the total of said vehicle.