EP3585766A1

EP3585766A1 - Liquid urea hydrohalides

Info

Publication number: EP3585766A1
Application number: EP18756858.9A
Authority: EP
Inventors: Shlomo Antebi
Original assignee: Bromine Compounds Ltd
Current assignee: Bromine Compounds Ltd
Priority date: 2017-02-23
Filing date: 2018-02-08
Publication date: 2020-01-01
Also published as: WO2018154560A1; EP3585766A4; CN110382459A; JP2020508321A

Abstract

The invention provides aqueous hydrohalide liquid compositions containing more than 50% hydrohalide and less than 8% water. A method is provided for preparing a composition containing up to 95% urea hydrobromide, which is liquid at ambient temperature.

Description

LIQUID UREA HYDROHALIDES

Field of the Invention

The present invention relates to liquid compositions comprising concentrated hydrohalides and to a process for preparing them. Particularly, the invention provides highly concentrated urea hydrohalides in solution as precursors for manufacturing haloureas.

Background of the Invention

Urea hydrohalide aqueous solutions have been employed in preparing biocidal compositions, for example by dissolving urea in aqueous HBr or HC1 (see WO2013/132492 or WO2013/140402). It is advantageous to employ concentrated reagents, both from viewpoint of their usage, and their transport and storage. WO2013/132492 employed 48% HBr for mixing with excess of urea, providing mixtures containing less than 30% HBr and at least 30% water. Further increase of the HBr concentration required employing high vacuum and temperature, which not only complicated the process, but also resulted in an enhanced formation of byproducts, such as biuret. In order to decrease the required temperature, an organic solvent may be employed in the process while promoting water removal by azeotropic distillation, followed by the removal of the organic solvent. The mentioned processes are time and energy consuming, and they produce undesired wastes. Therefore, it is an object of this invention to provide a highly concentrated solution of urea hydrobromide in a relatively simple and cost- effective process.

It is another object of this invention to provide a method for producing concentrated liquid urea hydrohalides, while obviating distillation steps. It is a further object of this invention to provide a method for producing the concentrated liquid urea hydrohalides, while obviating the use of organic solvents.

It is a still further object of this invention to provide a stable, highly concentrated liquid composition comprising urea hydrohalide, for preparing biocide formulations.

It is also an object of the invention to provide highly concentrated liquid urea hydrohalides comprising bromide and/or chloride precursors for making bromo- and chloro-based biocides.

It is a still another object of the invention to provide stable liquids with a high content of HBr, optionally in mixtures with HC1.

Other objects and advantages of the present invention will appear as the description proceeds.

Summary of the Invention

The invention provides a composition being liquid at room temperature and comprising urea hydrohalide of formula

(NH₂)₂CO . HX

in which (NH₂)₂CO is urea and HX is hydrogen halide, wherein the composition comprises at least 35% of hydrogen halide HX and at most 25% water. The term "%" relates to weight %. The composition preferably comprises at least 40% of hydrogen halide and at most 12% water. Said hydrogen halide is selected from HBr and HC1. In a preferred embodiment, HX in the composition according to the invention is HBr, and said urea hydrohalide has formula

(NH₂)₂CO . HBr . In another preferred embodiment, HX is a mixture of HC1 and HBr, and the composition of the invention comprises a mixture of urea hydrobromide of formula (NH₂)₂CO.HBr, and urea hydrochloride of formula (NH₂)₂CO.HCl. In one embodiment, the mixture of HC1 and HBr is equimolar.

In a first preferred aspect of the invention, the liquid composition comprises at least 50% HBr and at most 12% water, such as at least 52% HBr and at most 8% water, for example at least 53% HBr and at most 7% water. In a second preferred aspect of the invention, the liquid composition comprises at least 30% HBr, at least 13% HC1, and at most 12% water, such as at least 31% HBr, at least 14% HC1, and at most 8% water.

The invention provides a liquid composition comprising at least one urea hydrohalide of formula (NH₂)₂CO . HX, wherein HX is selected from HBr and HC1, the hydrohalide(s) constituting at least 85% of the composition, such as at least 90% of the composition. Water preferably constitutes between 4% and 12% of the composition. The composition may comprise free urea at a concentration of up to 5%, such as up to 4%, for example up to 3%, for example up to 2%, for example up to 1%. The composition may also comprise free HBr or HC1 or their mixture at a concentration of up to 5%, such as up to 4%, for example up to 3%, for example up to 2%, for example up to 1%. The composition is liquid at ambient temperature, usually between 15^QC and 35^QC, such as between 20^QC and 30^QC, for example 25^QC. Lowering the temperature or lowering the water content may be utilized for solidifying the composition if needed, which may be useful in some applications.

The invention provides a process for preparing a composition comprising at least one urea hydrohalide of formula (NH₂)₂CO . HX in which (NH₂)₂CO is urea and HX is hydrogen halide selected from HBr and HC1, wherein the composition comprises at least 35% of hydrogen halide HX and at most 25% water, comprising steps of i) adding solid urea to water or to an aqueous hydrogen halide solution, thereby obtaining an aqueous slurry of urea; and ii) incorporating into said slurry of step i) gaseous hydrogen halide or halides, thereby dissolving said slurry and obtaining a solution of urea hydrohalide(s), while cooling the reaction mixture to a temperature below 90^QC, such as to a temperature up to 70^QC, preferably up to 60^QC; the composition being liquid or solid at ambient temperature. In one aspect of the invention, a composition comprising urea hydrohalide at a concentration of up to 95% and being liquid at ambient temperature is provided by the process. In another aspect of the invention, a composition comprising urea hydrohalide at a concentration of at least 80%, such as at least 90% is provided, where the hydrohalide, preferably HBr, constitutes at least 45% of the composition, more preferably at least 50%, such as at least 52%, for example at least 54%, for example at least 56%; at ambient temperature, the composition may be liquid or wax-like solid. In a still another aspect, the composition provided by the process comprises a molar excess of urea over the hydrohalide.

The invention provides a process for preparing the hydrohalide compositions as described above, comprising steps of i) adding solid urea to water or to an aqueous hydrogen halide solution, thereby obtaining an aqueous slurry of urea; and ii) incorporating into said slurry of step i) gaseous hydrogen halide, thereby dissolving said slurry and obtaining a solution of urea hydrohalide; while cooling the reaction mixture to a temperature preferably between 15 and 60⁹C. Said hydrogen halide in step i) is selected from HBr and HC1; independently, said gaseous hydrogen halide in step ii) is selected from HBr and HC1. In one embodiment of the process according to the invention, a second portion of urea is added into said solution of urea hydrohalide, thereby obtaining a second slurry, followed by adding a second portion of gaseous hydrogen halide into said second slurry, thereby dissolving said second slurry and obtaining a second solution of urea hydrohalide. The process according to the invention preferably comprises a step of determining the content of at least one of the components in said solution of urea hydrohalide, wherein said component is selected from the group consisting of water, HBr, and HC1, followed by a step of adding at least one of the reagents selected from urea, HBr, and HC1 if the determined content value(s) differ from the predetermined values.

Detailed Description of the Invention

It has now been found that highly concentrated urea hydrobromide liquids can be obtained by treating urea slurries with hydrogen bromide gas. For example, high urea hydrobromide (denoted as "urea.HBr") concentrations were achieved by introducing HBr gas into urea slurries in minimal volumes of water or aqueous HBr; it has been found that the slurry is quickly dissolved by the formation of soluble urea hydrobromide during an exothermic reaction. This reaction advantageously provides more urea and more HBr in the solution, while reducing the concentration of water in the solution. The concentration of water can be regulated to a desired level, for example to the values of up to 10%. Thus, for example, a highly concentrated urea hydrobromide solution is obtained, containing water at a level as low as 8% or less, for example as low as 7% or less, such as 6% or less. The HBr content may be adjusted to as high as at least 50%, for example at least 51%, such as at least 52%, or at least 53%, or at least 54%. Unexpectedly, freely flowing liquids were obtained at ambient temperature even at a urea.HBr concentration of as high as 93% or even 95%. These liquids can be advantageously employed as precursors and reagents in preparing biocidal mixtures, for example when reacted with oxidants such as NaOCl, while obtaining the desired active agent in a wide range of concentrations. The high concentration of the non- aqueous components allows for flexible use of the precursor and, moreover, it reduces the cost of transport; the high concentration of the components further results in increased stability of urea hydrobromide. Long shelf lives were obtained even at temperatures higher than 30°C, such as 40°C or higher. Such stabilities enable to employ the reagents and precursors of the invention at any practical ambient temperature.

Hydrogen halide gas or gases can be employed for the preparation of urea hydrohalides or mixtures thereof, advantageously employed in preparing biocidal mixtures comprising chlorourea, bromourea, or mixtures thereof. In one embodiment of the invention, an aqueous HC1 solution (for example comprising from 32% to 37%) can be employed; however, gaseous HC1 is preferably used. In some applications, aqueous HBr may be employed at first stages of the process according to the invention. In other applications, liquid and/or gaseous HBr is employed, followed by employing gaseous HC1. This method enables to provide the desired high concentrations of HC1 and/or HBr in the biocide preparations.

The new method of preparing highly concentrated liquid urea hydrohalides was experimentally compared with various alternatives, partly employed by the inventors in their previous activities (see, WO2013/132492). Among alternative procedures, also the following procedures and steps were examined^ a) high vacuum distillation (2 mmHg at high temperature) of urea hydrobromide (urea. HBr) solutions! b) azeotropic distillation with an organic solvent (hexane or heptane) of urea. HBr solution (urea^HBr = 2- 1. l) followed by removing the organic solvent; c) bubbling HBr gas in an ethanol urea slurry, followed by removing ethanol in vacuum distillation (30 mmHg). The preferred procedure of the invention includes bubbling HBr gas through urea slurry followed by adding further solid urea, and further HBr gas. The comparative tests clearly demonstrated the advantages of the method according to the invention, including obviating the complex steps of distilling or employing organic solvents. The method of the invention provides the needed mixtures, without side product wastes. An important object of the invention is to provide a highly concentrated urea hydrohalide salt in a liquid state. The invention, for example, provides liquid urea hydrobromide, comprising HBr in a concentration as high as 53%. The method of preparing a highly concentrated urea hydrohalide according to the invention comprises a step of providing a urea slurry in water, and a step of admixing gaseous hydrogen halide into the slurry. The process is controlled by mild cooling, the reaction being carried out at temperatures lower than 75°C, usually at relatively low temperatures, such as lower than 40°C, for example lower than 30°C. It can be performed at a temperature equal to ambient temperature. In the method according to the invention, urea is incorporated into the reaction mixture gradually, so that it can be continually solubilized. In one embodiment, a first portion of urea in slurry is solubilized by adding a first portion of hydrogen halide, followed by adding a second portion of urea and hydrogen halide, and so on. In one embodiment, solid urea and gaseous HBr are added in many small increments or continually to the reaction mixture. The lowest achievable amount of water is several percent above zero, the compositions according to the inventions preferably comprising at least 4% water, corresponding to the highest achievable amount of HBr of about 55%. In a preferred embodiment, the invention provides urea. HBr compositions as concentrated as about 95% while being liquid at ambient temperature. The invention provides, for example, liquid compositions containing urea. HBr as concentrated as at least 88%, such as at least 92%, such as at least 94%, which comprise HBr at concentrations of at least, about 50%, about 53%, or about 54%, respectively.

The process of the invention provides, for example, concentrated urea hydrobromide, comprising the steps of preparing a urea slurry with calculated amounts of urea and water, followed by adding gaseous HBr, whereby dissolving the slurry, possibly adding the reagents in several steps, until obtaining the desired water content and the desired HBr content. The process according to the invention obviates employing evaporation, while achieving highest HBr content in the final salt product. Minimal amount of water allowed in the final product advantageously renders the product liquid, despite its surprisingly small concentration as low as 6% or less. The process comprising additions of solid urea and gaseous HBr can employ organic solvent, i.e., EtOH, but the preferred solvent is water. This concentrated product of the invention can serve as a useful intermediate, for example in making biocidal compositions, being produced in a cost-effective procedure, being easily transported and stably stored, even in high ambient temperatures, for example up to about 40°C.

The process of the invention can be modified to provide compositions containing high concentrations of HBr and/or HCl and low concentrations of water, and amides used as stabilizers for active halogen solutions. Such compositions are particularly useful as intermediates in preparing biocidal formulations. Said stabilizers may comprise urea derivatives, sulfamic acid, cyanoacetamide, or alkyl hydantoins. Highly concentrated stabilizer- hydrohalide liquids can be obtained by treating a slurry of stabilizer or stabilizers with a hydrohalide gas. For example, high stabilizer-hydrobromide concentrations are achieved by introducing HBr gas into a slurry with a minimum amount of water or a minimum amount of aqueous HBr solution; stabilizer slurry dissolves, usually during an exothermic reaction which increases the amount of stabilizer and HBr in solution while reducing the relative amount of water.

The invention provides a composition which is liquid at room temperature and comprises a high concentration of urea hydrohalide of formula

(NH₂)₂CO . HX

in which (NH₂)₂CO is urea and X is halogen, wherein the composition comprises at least 35% of hydrogen halide HX and at most 30% water, and wherein HX stands for HBr or HCl or their mixture. In a preferred embodiment of the invention, HX is HBr. In another preferred embodiment, HX stands for an equimolar mixture of HBr and HCl. In a preferred embodiment of the invention, said composition comprises at least 40% of hydrogen halide and at most 20% water, such as at least 45% of hydrogen halide and at most 10% water. In a preferred embodiment, the invention provides an aqueous liquid at ambient temperature consisting of urea hydrohalide and water in an amount as low as up to 9%, for example up to 8%, for example up to 7%, for example up to 6%, for example up to 5%. In one preferred embodiment of the invention, the composition comprises urea with HBr in the equimolar ratio and water, wherein water constitutes from 4 to 12% of the composition. In one embodiment, the invention provides a urea hydrobromide composition comprising at least 50% HBr, such as at least 51% HBr, such as at least 52% HBr, for example at least 53% HBr, for example at least 54%, for example at least 55% HBr. In another preferred embodiment of the invention, the composition comprises urea with semimolar amount of HBr and semimolar amount of HCl, and water constituting from 4 to 12% of the composition. In one embodiment, the invention provides a composition comprising a mixture of urea. HBr and urea. HCl containing at least 43% HBr+HCl, such as at least 44% HBr+HCl, such as at least 45% HBr+HCl, for example at least 46% HBr+HCl, for example at least 47% HBr+HCl. In preferred examples, the compositions according to the invention comprise between about 5% water and about 9% water. The term "about X% water" means X% + 1% water in this context. Compositions according to these preferred embodiments contain up to about 9% water and at least 52% HBr, such as up to about 7% water and at least 53% HBr, for example about 6% water and about 54% HBr. The invention provides a process for preparing a composition which is liquid at room temperature and comprises a high concentration of urea hydrohalide of formula (NH₂)₂CO. HX in which formula said (NH₂)₂CO is urea and said X is halogen, the composition comprising at least 40% of hydrogen halide HX and at most 20% water, the process comprising steps of i) adding solid urea to water or to an aqueous hydrogen halide solution, thereby obtaining an aqueous slurry of urea; ii) incorporating gaseous hydrogen halide into said slurry, thereby obtaining a solution of urea hydrohalide; iii) determining the content of water or HX in said solution; and iv) if said water content is higher or said HX content is lower than a predetermined value, repeating steps i) to iii). In one embodiment, the process according to the invention comprises steps of i) adding a first portion of solid urea to water or to an aqueous hydrogen halide solution, thereby obtaining a first aqueous slurry of urea; ii) incorporating gaseous hydrogen halide into said first slurry, thereby obtaining a first solution of urea hydrohalide; iii) adding a second portion of solid urea to said first solution of urea hydrohalide, thereby obtaining a second aqueous slurry of urea; iv) incorporating hydrogen halide into said second slurry, thereby obtaining a second solution of urea hydrohalide; v) determining the content of water or HX in said second solution; and vi) if said water or HX content is lower than a predetermined value, repeating steps iv) and v). Said HX may be HBr or HCl. For example, if the desired product is liquid (NH₂)₂CO.HBr, said HX is HBr which is used at least partially as gas, preferably in several portions. If the desired product is a liquid mixture of (NH₂)₂CO.HBr and (NH₂)₂C0.HC1, said HX is HBr and HCl, preferably used separately, at least partially as gases, separately applied in at least two separate steps, each gas being possibly applied in several portions. The process according to the invention preferably comprises cooling the reaction mixture, preferably to a temperature between 15^QC and 90^QC, preferably up to 80^QC, such as between 15^QC and 60^QC.

Generally, in a method according to the invention, a stabilizer of active halogen is mixed with water or with aqueous HBr to provide a slurry, and predetermined amounts of gaseous HBr or HCl are introduced into the slurry, possibly in more steps and/or portions at a temperature of between ambient and 80°C. In a preferred embodiment of the invention, the stabilizer is urea, and provided is concentrated urea hydrobromide or urea hydrobromide/ hydrochloride in liquid form at ambient temperature. In accordance with required applications, the water content of the liquid is predetermined, usually in the range between 4% and 12%. A skilled worker will calculate the needed amounts of the reagents from the planned quantity of the final product, for example taking into consideration the fact that HBr is used in the equimolar amount relatively to urea when urea. HBr is produced (abbreviated below as U.Br), and that HBr and HC1 are used in semimolar amounts relatively to urea when urea. HBr + urea.HCl is produced (abbreviated below as U.Br. CI). The following table provides examples of pre-calculated reagent amounts per 100 g product for six embodiments of concentrated liquids according to the invention. For example, a product of urea hydrobromide comprising 8% water is denoted in the Table as U.Br.Cl(8).

Table 1 Reagent amounts in grams needed per 100 g of liquid urea

hydrohalide product

The invention will be further described and illustrated by the following examples.

Examples

Example 1

Preparation of solid urea hydrobromide (urea;HBr - 2:1.1 molar ratio) by water distillation Solid urea (98.6% pure; 17.64 g, Mw 60, 289.9 mmol) was dissolved in aq. 48% HBr (26.84 g; 12.9 g as 100%, Mw 80.92, 159.21 mmol) to give 44.5 g of solution (urea 39.1%, HBr 28.96%). Water (calcd. 13.95 g) was distilled off using a rotavapor (vacuum 3 mbar, with gradual heating (to 75°C) during 4 hours. 14.26 grams of water was removed. Analysis calcd: urea 57.45%, HBr 42.55%; Found: urea 56.1%, HBr 41.8%. A deliquescent solid of urea hydrobromide (urea. HBr) was obtained. The word "calculated" is abbreviated as "calcd". Example 2

Preparation of solid urea.HBr (urea;HBr - 3; 1.1 molar ratio) by evaporating water

Solid urea (98.6% pure; 26.6 g, Mw 60, 437.13 mmol) was dissolved in aq. 48% HBr (12.96 g as 100%, Mw 80.92, 160.16 mmol) to give 53.6 g of solution (urea 48.9%; HBr 24.2%). Water (14.04 g) was removed using a rotavapor, vacuum 2 mbar, with gradual heating (to 75°C) during 3.5 hours. 14.65 grams of water was removed. Analysis calcd.: urea 66.92%, HBr 33.08%. Found: urea 61.1%, HBr 32.7%. A deliquescent solid was obtained. Example 3

Preparation of solid urea.HBr (urea;HBr - 1;1 molar ratio) by evaporating water

Solid urea (98.6% pure; 8 g, Mw 60, 132.5 mmol) was dissolved in aq. 48% HBr (22.42g; 10.76g as 100%, Mw 80.92, 132.99 mmol) to give 30.5 g of solution (urea 26.09%, HBr 35.3). Water (12.8 g) was removed using a rotavapor, vacuum 2 mbar, with gradual heating (to 75°C) during 1.3 hrs. 14.65 grams of water was removed. Analysis: calcd.: urea 42.5%, HBr 57.5%. Found: urea 46.2%, HBr 52.7%, a deliquescent solid was obtained. Example 4

Preparation of solid urea.HBr (urea;HBr - 3;1.1 molar ratio) via azeotropic distillation with heptane: T_M 79.2°C

Solid urea (98.6% pure; 26.6 g, Mw 60, 437.1 mmol) was dissolved in aq. 48% HBr (27 g; 13 g as 100%, Mw 80.92, 160.2 mmol) to give 53.6 g of solution (urea 48.92%, HBr 24.2%). n-Heptane 95% (60.4, g) was added to the aqueous solution and azeotropic distillation started (150°C, 6 hrs) at atmospheric pressure followed by removal of heptane under vacuum. 14.3 g water was removed (calculated 14.04 g) leaving a white solid (m.p. 72.3-76°C). Analysis: urea 55.7%; HBr 38.7%; biuret 3.14%; H₂0 2.5% (calcd).

Example 5

Preparation of urea.HBr (urea;HBr - 1;1.0β molar ratio) by vacuum distillation with heptane

Solid urea (98.6% pure; 40.46 g, Mw 60, 655.7 mmol) was dissolved in aq. 48% HBr (117.55g; 56.4 g as 100%, Mw 80.92, 697.3 mmol) to give 157.45 g of solution; D= 1.419g/l. (urea 25%, HBr 35.84%). n-Heptane 95% (123.4, g) was added to the aqueous solution. Distillation under pressure (80°C, 32-43 mbar, 1 hr,) gave 97.45 g of a liquid that solidified to a wax-like residue having a ratio of 1:0.97 urea:HBr molar ratio, urea 41.55%; HBr 54.6%; biuret 0.4%; H₂0 2.5% (calcd).

Example 6

Preparation of liquid urea.HBr (urea;HBr - 1.1.07 molar ratio) by vacuum distillation with heptane

Solid urea (98.6% pure; 40.46 g, Mw 60, 655.7 mmol) was dissolved in aq. 48% HBr (118.04g; 56.7 g as pure, Mw 80.92, 700.2 mmol) to give 157.9 g of solution; D= 1.419g/l. (urea 24.9%, HBr 35.9%). n-Heptane 95% (123.4, g) was added to the aqueous solution. Distillation under pressure (80°C, 34-45 mbar, 1 hr) gave 97.45 g of residue of a clear solution (expected 96 g) consisting of urea hydrobromic salt having a 1:0.94 molar ratio of urea:HBr. D₂₅°_c 1.763g/l. urea 42.2%, HBr 53.6%; biuret 0.4%, 3.8% water.

Example 7

Preparation of liquid urea.HBr.HCl (urea;HBr;HCl = 1.17; 0.5;0.5 molar ratio) by vacuum distillation with heptane;water

Solid urea (98.6% pure; 66.93 g, Mw 60, 1100 mmol) was dissolved in aq. 48% HBr (79.5 g as 100%, Mw 80.92, 38.15 as pure, 471.43 mmol) and 32% aq. HC1 (53.6 g, 17.15 g as pure, Mw 36.45; 470.6) to give 200 g of solution; D= 1.317 g/1, urea 54%, HBr 19.07 %; HC1 8.58%; n-Heptane 95% (192, g) was added to the aqueous solution. Distillation under pressure (80°C, 26-38 mbar, 5 hrs,) gave 119.2 g of residue of a clear solution consisting of 1.18:0.5:0.36 molar ratio of urea:HBr:HCl. D_25SC 1.60g/l. Analysis:

Calcd: urea 54.41%, HBr 31.45% HC1 14.14%.

Found: urea 56.3%, HBr 32.2 %; HC1 10.38%. biuret 0.56%, water 0.56%.

Example 8

Preparation of solid urea.HBr (urea;HBr - 2:1.1 molar ratio) using HBr gas and ethanol as solvent

Solid urea (66.93 g, 98.6% pure, Mw 60, 1314 mmol) was added to ethanol (77.6 g) to obtain 157.6 g of a slurry, urea 50.04%, Ethanol 49.2%. HBr gas (58.55g; Mw 80.92, 723.55 mmol) was added with cooling, keeping the temperature below 30°C. A clear colorless solution consisting of 2:1.1 molar ratio of urea:HBr was obtained. Evaporation of the solvent (50°C, 2 hrs, 27 mBar) gave 76.8 g of a white deliquescent solid. The material solidifies at room temperature and a white solid was obtained.

Analysis found: urea 55.0%, HBr 41.7%, biuret 0.61%, pH (1% solution) 1.4; GC-MS ethanol (1.9% ). The molar ratio of urea:HBr is 1.95:1.1

Example 9

Preparation of solid urea.HBr (urea;HBr - 1;1 molar ratio) using

HBr gas and ethanol solvent Solid urea (65.38 g, 98.6% pure, Mw 60, 1074.4 mmol) was added to ethanol (63.9 g) to obtain 129.26 g of a slurry, urea 49.87%, Ethanol 49.37%). HBr gas (87.12; Mw 80.92, 1076.6 mmol) was added with cooling, keeping the temperature below 35°C. A clear colorless solution consisting of 1:1 molar ratio of urea:HBr was obtained. Evaporation of the solvent (50°C, 8 hrs, 23-27 mBar) gave 65.4 g of a white deliquescent solid. The material solidifies at room temperature and a white solid was obtained.

Analysis: found: urea 41.7%, HBr 52.9%, biuret 0.4%, pH (1% solution) 1.36; GC-MS ethanol (3.9% ). The molar ratio of urea:HBr is 1.06:1.

Example 10

Preparation of liquid concentrated urea.HBr, 11% water (urea;HBr - 1:1 molar ratio) using HBr gas

Solid urea (66 g, 98.6% pure, Mw 60, 1099.3 mmol) was added into water (19.4 g, endothermic) to obtain 85.4 g of a slurry, urea 76.1%, H₂0 22.78%. The HBr gas (88 g; Mw 80.92, 1087.4 mmol) was added slowly (1 hr exothermic) while cooling, keeping the temperature below 35°C. A clear colorless solution consisting of 1:1 molar ratio of urea:HBr was obtained. Analysis (found): urea 37.5%, HBr 50.9 %, biuret 0.34 %, H₂0 11.3%, pH (1% solution) 1.37.

Example 11

Preparation of liquid urea.HBr, 6% water (urea;HBr - 1;1 molar ratio) with HBr gas

Solid urea (43.6 g, 98.6% pure, Mw 60, 716.2 mmol) was added into water (12.84 g, endothermic) to obtain 56.4 g of a slurry (urea 76.1%, H₂0 22.8%). The HBr gas 25.75g (Mw 80.92, 318.09 mmol) was added slowly (15 min. exothermic) while cooling, keeping the temperature below 35°C. A clear colorless solution was obtained. A second urea dose (47.08, Mw 60, 773.68 mmol) was added to the solution forming again a slurry (making a total of 90.66, Mw 60, 1489.84 mmol). HBr gas was added again until a total of 119.4 g (Mw 80.92, 1475.53 mmol) was weighed (exothermic). A clear and colorless solution was obtained with 6.2% H₂0 (calcd).

Analysis (found): urea 39.9%, HBr 53.5%, biuret 0.39%, pH (1%) 1.42.

The solution was stable for 4 months at 40°C without decomposition.

Example 12

Preparation of liquid urea.HBr.HCl (urea;HBr;HCl - 1;0.5;0.5 molar ratio) using HBr gas and 32% aq. HCl

Solid urea (80.94 g, 98.6% pure, Mw 60; 1330 mmol) was added into aq. 32% HCl (76.09g; 24.35g as 100%, Mw 36.42, 668.01 mmol) to produce 157.02 g of a clear solution; urea 50.8%, HCl 15.5%, H₂0 32.95%.

Then HBr gas 62.86 g (Mw 80.92, 776.8 mmol) was added slowly (48 min. exothermic) while cooling, keeping the temperature below 35°C. A clear colorless solution was obtained. Urea 37.9%, HBr 26.02%, HCl 11.21%; biuret 0.39%; pH (1%) 1.28; 24.5% H₂0 (calcd).

The solution was stable for 3 months at 40°C without decomposing

Example 13

Preparation of liquid urea.HBr.HCl (urea;HBr;HCl - 1;0.5;0.5 molar ratio) using HBr gas and aq. 37% HCl

Solid urea (81.5 g, 98.6% pure, Mw 60; 1336.8 mmol) was added into aq. 37% HCl (65.81g; 24.35 g as 100%, Mw 36.42, 668.03 mmol) to produce 146.74 g of a clear solution; urea 54.38 %, HCl 16.6.5%, H₂0 28.25%.

Then HBr gas (61.4 g; Mw 80.92, 758.77 mmol) was added slowly (40 min. exothermic) while cooling, keeping the temperature below 35°C. A clear colorless solution was obtained D= 1.4550.

Analysis (calcld.): urea 39.85%, HBr 26.87%, HCl 12.1%, H₂0 20.61%, D₂₃₅._c 1.455 g/1.

Analysis found: urea 40.4%, HBr 27.14%, HCl 11.85%; biuret 0.39%, pH (1%) 1.26. Example 14

Preparation of liquid urea.HBr. 7% water (urea;HBr - 1;1 molar ratio) using HBr gas

Solid urea (114 g, 98.6% pure, Mw 60; 1873.9 mmol) was added into aq. 48% HBr (38.53 g; 18.494 g as 100%, Mw 80.92, 228.55 mmol) to produce 152.5 g of a clear solution; urea 73.7 %, HBr 12.12%, H₂0 13.13%.

Then HBr gas (154.14 g; Mw 80.92, 1873 mmol) was added slowly (62 min. exothermic) while cooling, keeping the temperature below 50°C. A clear colorless solution 288.21g (163.94ml) was obtained; D₂₆₉._c 1.758g/l.

Analysis (calcd.): urea 39.01%, HBr 53.48%, H₂0 6.95%, D₂₆₉._c 1.758g/l.

Analysis found: urea 40%, HBr 53.2%, biuret 0.41%, pH (1%) 1.23.

After 7 hrs at 50°C the analysis is the same: urea 40%, HBr 53.2%, biuret 0.41%, pH (1%) 1.23. Example 15

Preparation of bromourea (urea;HBr;NaOCl - 1;1;0.85 molar ratio)

Urea hydrobromide solution {6.3 g, urea 41.4 mmol and HBr 41.4 mmol} (Example 14) was diluted in 244 g H₂0.

In a separate flask aq. NaOCl solution ( 25.9 g, 9.65% as Cl₂ w/w; 2.5 g, 35.2 mmol) was diluted with 223 g H₂0).

The two solutions were mixed to give 499.25 g of a biocide solution (0.5 % as Cl₂). The solution had the same biocidal efficacy as prepared by the less condensed form.

Example 16

Preparation of liquid urea.HBr, 8% water (urea;HBr - 1;1 molar ratio) using HBr gas

Solid urea (106.23 g, 98.6% pure, Mw 60; 1745.7 mmol) was added into aq. 48% HBr (38.53 g; 18.494 g as 100%, Mw 80.92, 228.55 mmol) to produce 146.26 g of a clear solution; urea 71.6 %, HBr 12.64%, H₂0 14.72%. Then HBr gas was added slowly (35 min. exothermic) (to a total of 141.25 g; Mw 80.92, 1745.6 mmol) while cooling, keeping the temperature below 60°C. A clear colorless solution 269 g (154.25 ml) was obtained; D₂₉₅._c 1.744 g/1.

Analysis calcd: urea 38.93%, HBr 52.5%, H₂0 8 %.

Analysis found: urea 39.1%, HBr 52.6%, biuret 0.37%, pH (1%)1.27, D₂₅._c 1.746g/l . After 7 hrs at 50°C: urea 39.2%, HBr 52.5%, biuret 0.37%, pH (1%) 1.26.

Example 17

Preparation of liquid urea.HBr, 9% water (urea;HBr - 1;1 molar ratio) using HBr gas

Solid urea (105.4 g, 98.6% pure, Mw 60; 1732.07 mmol) was added into aq. 48% HBr (40.41 g; 19.4 g as 100%, Mw 80.92, 239.74 mmol) to produce 145.81 g of a clear solution; urea 69.7 %, HBr 13 %, H₂0 16.3 %.

Then HBr gas was added slowly (35 min. exothermic) (to a total of 141.25 g; Mw 80.92, 1732.7 mmol) while cooling, keeping the temperature below 60°C. A clear colorless solution 269.9 g (154.84 ml) was obtained; D_{2g 5}._c 1.734 g/1. Analysis calcd: urea 38.8%, HBr 51.95%, H₂0 9%.

Analysis Found: urea 38.8%, HBr 52%, biuret 0.37%, pH (1%)1.25, D₂₅._c 1.743 g/1 .

After 7 hrs at 50°C: urea 39.4%, HBr 51.9 %, biuret 0.35%, pH (1%) 1.26.

Example 18

Preparation of liquid urea.HBr, 6% water (urea;HBr - 1;1 molar ratio) using HBr gas

Solid urea (105.98 g, 98.6% pure, Mw 60; 1741.5 mmol) was added into aq. 48% HBr (24.7 g; 11.85 g as 100%, Mw 80.92, 146.44 mmol) to produce 130.7 g of a clear solution; urea 80 %, HBr 9.07%, H₂0 9.83 %.

Then HBr gas was added slowly (53 min. exothermic) (to a total of 140.92 g; Mw 80.92, 1741.5 mmol) while cooling, keeping the temperature below 50°C. A clear colorless solution 262.9 g (148.9 ml) was obtained; D₂₈._c 1.76 g/1.

Analysis calcd: urea 39.9%, HBr 53.85%, H₂0 5.8%. Analysis found: urea 40.3%, HBr 52.8%, biuret 0.41%, pH (1%) 1.25, D₃₃._c 1.759 g/1.

After 7 hrs at 50°C: urea 40%, HBr 53 %, biuret 0.42%, pH (1%) 1.26. Example 19

Preparation of liquid urea.HBr.HCl, 7% water (urea;HBr;HCl - 1;0.5;0.5 molar ratio) using HBr gas and HC1 gas

Solid urea (80.93 g, 98.6% pure, Mw 60; 1329.95 mmol) was added into aq.

48% HBr (20 g; 9.6 g as 100%, Mw 80.92, 118.64 mmol) to produce 100.93 g of a slurry solution; urea 79.06 %, HBr 9.51%, H₂0 10.3 %.

Then HBr gas was added slowly (50 min. exothermic) (to a total of 54.06 g;

Mw 80.92, 668.07 mmol) while cooling, keeping the temperature below 60°C.

HC1 gas (24.35 g; Mw 36.45, 668.04 mmol) was added slowly during 25 min. while cooling, keeping the temperature below 60°C. A clear colorless solution 169.74 g.

Analysis (calcd.): urea 47%, HBr 31.85%, HC1 14.35 %; H₂0 6.13%.

Example 20

Preparation of concentrated urea.HBr.HCl, 7% water (urea;HBr;HCl - 1.2;0.5;0.5 molar ratio) using HBr gas and HC1 gas

Solid urea (97.2g; 98.6% pure, Mw 60; 1597.3 mmol) was added into aq. 48%

HBr (22.5 g; 10.8 g as 100%, Mw 80.92, 133.47 mmol) to produce 119.7 g of a a slurry solution; urea 80.07 %, HBr 9 %, H₂0 9.77 %.

Then HBr gas was added slowly (50 min. exothermic) (to a total of 54.06 g;

Mw 80.92, 668.07 mmol) while cooling, keeping the temperature below 60°C.

HC1 gas (24.35g; Mw 36.45, 668.04 mmol) was added slowly during 25 min. while cooling, keeping the temperature below 60°C. A clear colorless solution

187.3 g was obtained.

Analysis: urea 51.17%, HBr 28.9%, HC1 13%, H₂0 6.25%. While the invention has been described using some specific examples, many modifications and variations are possible. It is therefore understood that the invention is not intended to be limited in any way, other than by the scope of the appended claims.

Claims

1. A composition being liquid at room temperature and comprising urea hydrohalide of formula

(NH₂)₂CO . HX

in which (NH₂)₂CO is urea and HX is hydrogen halide,

wherein the composition comprises at least 35% of hydrogen halide HX and at most 25% water.

2. A composition according to claim 1, comprising at least 40% of hydrogen halide and at most 12% water.

3. A composition according to any one of claims 1 to 2, wherein HX is HBr or HC1.

4. A composition according to any one of claims 1 to 2, wherein said HX is HBr, and said urea hydrohalide has formula

(NH₂)₂CO . HBr .

5. A composition according to any one of claims 1 to 3, wherein said HX is a mixture of HC1 and HBr.

6. A composition according to claim 4, comprising at least 50% HBr and at most 12% water.

7. A composition according to claim 6, comprising at least 52% HBr and at most 8% water.

8. A composition according to claim 7, comprising at least 53% HBr and at most 7% water.

9. A composition according to claim 5, comprising at least 30% HBr, at least 13% HC1, and at most 12% water.

10. A composition according to claim 9, comprising at least 31% HBr, at least 14% HC1, and at most 8% water.

11. A composition according to any one of claims 1 to 10, comprising at least 4% water.

12. A process for preparing the hydrohalide compositions of any one of claims 1 to 11, comprising steps of

i) adding solid urea to water or to an aqueous hydrogen halide solution, thereby obtaining an aqueous slurry of urea; and ii) incorporating into said slurry of step i) gaseous hydrogen halide(s), thereby dissolving said slurry and obtaining a solution of urea hydrohalide(s);

while cooling the reaction mixture to a temperature between 15 and 60°C.

13. A process according to claim 12, wherein said hydrogen halide in step i) is selected from HBr and HC1.

14. A process according to claim 13, wherein said gaseous hydrohen halide in step ii) is selected from HBr and HC1.

15. A process according to claim 14, comprising adding a second portion of urea into said solution of urea hydrohalide, thereby obtaining a second slurry, and adding a second portion of gaseous hydrogen halide into said second slurry, thereby dissolving said second slurry and obtaining a second solution of urea hydrohalide. A process according to any one of claims 12 to 15, further comprising a step of determining the content of at least one of the components in said solution of urea hydrohalide, wherein said component is selected from the group consisting of water, HBr, and HCl, followed by a step of adding at least one of the reagents selected from urea, HBr, and HCl if the determined content values differ from the predetermined values.