Stabilized dialkyl dicarbonates having encanced action

Abstract

The invention relates to mixtures containing dialkyl dicarbonates and benzaldehyde and / or the derivatives thereof, to a process of production and to the use thereof for sterilizing and preserving food and drinks against invasion and / or decomposition by microorganisms.

Description

[0001] Stabilized and enhanced dialkyl dicarbonates

[0002] The invention relates to mixtures containing dialkyl dicarbonates and benzaldehyde and / or its derivatives, a process for their preparation and their use for sterilizing and preserving foodstuffs and beverages against attack and / or decomposition by microorganisms.

[0003] Dialkyl dicarbonates, particularly dimethyl dicarbonate and diethyl dicarbonate, are used in the beverage industry for the cold sterilization of non-alcoholic carbonated or still fruit juice drinks, fruit juices, wines, non-alcoholic wines, ciders, iced teas, and other beverages. This beverage stabilization technology offers a number of advantages. The most notable advantage is that, unlike hot filling, taste and color are not affected. Compared to persistent preservatives such as sodium benzoate or benzoic acid or potassium sorbate or sorbic acid, the advantage is particularly the absence of any taste impairment. Compared to cold aseptic filling, the significantly lower investment costs for plant technology are a particularly well-known advantage of using dialkyl dicarbonates.

[0004] Of particular note is the antimicrobial activity of dimethyl dicarbonate, which is very effective against bacteria, yeasts, and fungi. The regulatory maximum use concentrations of 250 ppm dimethyl dicarbonate in non-alcoholic soft drinks and 200 ppm in wine completely suppress and inactivate the harmful microorganisms in most cases. However, there are applications in which an even further improved antimicrobial effectiveness of dimethyl dicarbonate would be desirable. This can be particularly the case when, from an operational perspective, optimal plant hygiene cannot be guaranteed. There can be various reasons for this, such as the training of the available workforce, the age of the plants or plant components, the quality of the ingredients, or even the economic requirements and possibilities of the entire production process.For these reasons, enhancing the effect of dialkyl dicarbonates, especially dimethyl dicarbonate, is particularly interesting.

[0005] The substance class of dialkyl dicarbonates has the special property of hydrolyzing into the derived alcohols and carbon dioxide upon contact with corresponding beverages. Depending on the temperature of the beverage during use, the active substance is therefore no longer present in the beverage after a relatively short time. At typical temperatures between 5 and 20 °C, this occurs after a few hours. However, hydrolysis is also initiated by even the smallest amounts of water.

[0006] The decomposition of dialkyl dicarbonates is not limited to hydrolysis; degradation also occurs through spontaneous or thermal decarboxylation. This produces carbon dioxide and dialkyl carbonate. Since the chemical stability of dimethyl dicarbonate is generally low and there is a fundamental tendency toward hydrolysis and decarboxylation, methods for stabilizing dialkyl dicarbonates during production, storage, and transport have been described.

[0007] For example, EP 2016041 B1 discloses that dialkyl dicarbonates can be stabilized by the presence of acids during distillation, storage, and / or transport. EP 2013160 B1 discloses the stabilization of dialkyl dicarbonates using phosphorus compounds. EP 2024318 B1 describes the stabilization of dialkyl dicarbonates using finely divided additives. However, the effect of such additives depends on the amount used and cannot be increased indefinitely. Depending on the specific application, precipitation may occur, for example, so that the finely divided additives cannot be used for preservation in every beverage application.

[0008] The task therefore remained to find stable and effective mixtures containing dialkyl dicarbonates with which the disadvantages of the prior art can be overcome.

[0009] Surprisingly, it has now been found that mixtures containing dialkyl dicarbonates and benzaldehyde or / and its derivatives are both more stable and more effective than dialkyl dicarbonates.

[0010] The invention therefore relates to a mixture containing at least one compound of formula (I) where

[0011] R 1 and R 2 independently of one another represent straight-chain or branched Ci-C8-alkyl, cycloalkyl, C2-C8-alkenyl, C2-C8-alkynyl or benzyl in an amount > 90 wt.%, and at least one compound of the formula (II) where

[0012] R 3 and R 4 independently of one another represent H, CI or straight-chain or branched Ci-C8-alkyl, in an amount of 1*10 -6 Wt.% to 0.1 wt.% based on the total weight of the mixture.

[0013] Preference is given to R 1 and R 2independently of one another represent straight-chain or branched Ci-Cs-alkyl, C2-C8-alkenyl, phenyl or benzyl.

[0014] Particularly preferred are R 1 and R 2 independently represent straight-chain or branched Ci-C5 alkyl, C3 alkenyl or benzyl.

[0015] Particularly preferred are R 1 and R 2 independently represent methyl or ethyl.

[0016] In a further embodiment, the compounds of formula (I) are dimethyl dicarbonate, diethyl dicarbonate, di-isopropyl dicarbonate, di-n-propyl dicarbonate and di-tert-butyl dicarbonate.

[0017] The compounds of formula (I) are very particularly preferred as dimethyl dicarbonate or diethyl dicarbonate, or mixtures of these compounds. Even more preferred is the compound of formula (I) as dimethyl dicarbonate.

[0018] Preference is given to R 3 and R 4independently represent straight-chain or branched Ci-C4 alkyl and H.

[0019] Particularly preferred are R 3 and R 4 independently represent methyl, ethyl or H.

[0020] Preferably, the compounds of formula (II) are 2-methylbenzaldehyde, 3-

[0021] Methylbenzaldehyde, 4-methylbenzaldehyde, 2-ethylbenzaldehyde, 3-ethylbenzaldehyde, 4-ethylbenzaldehyde, 2-methyl-3-ethylbenzaldehyde, 3-methyl-4-ethylbenzaldehyde and benzaldehyde or mixtures of these compounds.

[0022] Even more preferred is the compound of formula (II) benzaldehyde.

[0023] The mixture preferably contains at least 99.75 wt.% of the compounds of formula (I) and 1*10 -6 Wt.% to 0.1 wt.% of compounds of formula (II).

[0024] Even more preferably, the mixture contains at least 99.75 wt.% of compounds of formula (I) and 1*10 -6 Wt.% up to 5*10 -4% by weight of the compounds of formula (II).

[0025] In a further embodiment of the invention, the mixture contains at least 99.75 wt.% of compounds of formula (I) and 1*10 -5 Wt.% up to 1*10 -3 Wt.% of the compounds of formula (II). This corresponds to a weight ratio of 0.1 ppm to 10 ppm of the compounds of formula (II) based on the weight of the compounds of formula (I) used.

[0026] The mixtures may also contain other compounds, such as phosphorus compounds, preferably phosphates or phosphoric acid, or other stabilizers, such as, for example, and preferably, organic carboxylic acids. However, impurities such as, for example, and preferably, methanol and / or dimethyl carbonate may also be present. Carbon dioxide may also be present. Impurities such as methanol and dimethyl carbonate may preferably be present in an amount of <9.9 wt.%, based on the total weight of the mixture according to the invention. If methanol and dimethyl dicarbonate are present, then particularly preferably in an amount of 0.01 wt.% to 0.24 wt.%, based on the total weight of the mixture according to the invention.If the mixtures contain further compounds, such as preferably phosphoric acid, these are preferably present in a weight ratio of 0.01 ppm to 50 ppm based on the weight of the total compounds in the mixture.

[0027] Preferably, the mixture contains, in addition to compounds of formula (I) and (II), methanol and dimethyl carbonate and optionally phosphoric acid.

[0028] In a preferred embodiment, the mixture contains at least 99.8 wt.% dimethyl dicarbonate, 1*10 -6 Wt.% up to 5*10 -4 % by weight of the compounds of formula (II), in particular benzaldehyde, 5*10 -3 Wt.% up to 1*10 -6 wt.% phosphoric acid and the remainder comprises methanol and dimethyl carbonate. The mixture particularly preferably contains 99.8 wt.% dimethyl dicarbonate, 1*10 -6 Wt.% up to 5*10 -4 % by weight of the compounds of formula (II), in particular benzaldehyde, 5*10 -3 Wt.% up to 1*10 -6Wt.% phosphoric acid and the rest is methanol and dimethyl carbonate.

[0029] The mixtures according to the invention can be stored for a period of several months without decomposition of more than 0.05 wt.% of the dialkyl dicarbonates contained therein. The mixtures according to the invention can preferably be stored for a period of at least 3 months without decomposition of more than 0.05 wt.% (50 ppm) of the dialkyl dicarbonates contained therein. The temperature is preferably between 20°C and 40°C.

[0030] The mixtures according to the invention are excellently suited for the sterilization and preservation of foodstuffs and in particular beverages against infestation and / or decomposition by microorganisms.

[0031] The present invention therefore also relates to the use of the mixtures according to the invention for sterilizing and preserving foodstuffs and beverages against infestation and / or decomposition by microorganisms, such as preferably bacteria, fungi, or yeasts. The mixtures according to the invention are preferably used for sterilizing and preserving beverages.

[0032] The mixtures according to the invention are, for example, outstandingly suitable as cold disinfectants for still or carbonated beverages, such as sports drinks, fruit juice-containing soft drinks with juice contents of 0.1 to 99%, nectars, juices, wine, wine-based beverages, mixed beer drinks, vitamin drinks, isotonic drinks, and energy drinks. They are also suitable for alcoholic, low-alcohol, and non-alcoholic beverages.

[0033] Typically and preferably, the mixtures according to the invention are added in a weight ratio of between 10 and 250 ppm based on the weight of the beverages and / or foodstuffs. The addition preferably takes place shortly after the beverages are filled. Mixing into the beverages is preferably carried out using special dosing pumps. The mixtures according to the invention have a controlling effect on a number of microorganisms such as fermentative yeasts, molds, or fermentative bacteria. Examples and preferred examples include Asaia bogorensis, Saccharomyces cerevisiae, Mycoderma, Brettanomyces spp., Lactobacillus brevis, and Lactobacillus buchneri. The invention also encompasses a process for producing the mixture according to the invention.To prepare the mixtures according to the invention, the compound of formula (II) can, for example and preferably, be used in liquid form, or the compound of formula (II) is used in powder form. The compound of formula (II) is mixed with the compound of formula (I), preferably with stirring. For this purpose, commercially available stirring devices can be used in addition to pumping via tank systems. To ensure uniform incorporation, pre-dilutions can also be used and these can then be slowly added to a product stream, for example via a three-way valve. The order of addition is not important here; preferably, the compound of formula (I) is initially taken and the compound of formula (II) is added, preferably in metered amounts.It is also possible to add the compound of formula (II) via a precursor, from which the compound of formula (II) is formed, for example, during the preparation of the compound of formula (I). The following examples are intended to illustrate the subject matter of the invention, but are not intended to limit it thereto.

[0034] Method for analysis

[0035] Analytical method for the determination of benzaldehyde in DMDC by LRI capillary gas chromatography / full-scan MS:

[0036] 3 g of DMDC are mixed with 20 mL of water and 10 mL of 50 wt% MgSO4. The mixture is then stirred for 24 h, and the DMDC is quantitatively hydrolyzed. To create a blank, 20 mL of water and 10 mL of 50 wt% MgSO4 are mixed and also stirred for 24 h.

[0037] After 24 h, 1 mL of an internal standard valeric acid pentyl ester solution is added, followed by 2 mL of the extraction solvent TBME (tert-butyl methyl ether), and extraction is carried out with shaking for at least 5 min. The organic phase is separated and detected by full-scan GC-MS on a Restek™ Rtx™ -5 (capillary column - 10 m length, general-purpose fused silica column for pharmaceuticals, solvent contaminants, pesticides, hydrocarbons, PCB congeners, essential oils, and semi-volatiles) in a shallow temperature gradient from 35 °C to 220 °C.

[0038]

[0039] Preparation of the inventive mixture 1

[0040] A 5-liter glass vessel is charged with 3.00 kg of dimethyl dicarbonate. The purity of the dimethyl dicarbonate is 99.95%. Thus, the amount of dimethyl dicarbonate in the glass vessel is also 99.95 wt.%. 3.0 mg of benzaldehyde are weighed, dissolved in 0.5 ml of dimethyl dicarbonate (99.95%), and pipetted into the 5-liter glass vessel. The mixture is stirred for 20 min. Mixture 1 is obtained, containing 1 ppm (1*10 -4 wt.%) Benzaldehyde.

[0041] Example 2

[0042] Preparation of the inventive mixture 2

[0043] A 5-liter glass vessel is charged with 3.00 kg of dimethyl dicarbonate. The purity of the dimethyl dicarbonate is 99.96%. Thus, the amount of dimethyl dicarbonate in the glass vessel is also 99.96 wt.%. 3.0 mg of benzaldehyde is weighed, dissolved in 5 ml of dimethyl dicarbonate (99.96%), mixed, and 0.5 ml of this mixture is taken and pipetted into the 5-liter glass vessel. The mixture is stirred for 20 min. Mixture 2 is obtained, containing 0.1 ppm (1*10 -5 wt.%) Benzaldehyde.

[0044] Example 3

[0045] Stability of the inventive mixture 1

[0046] Two vessels, one containing 1000 ml of Mixture 1 from Example 1 (Vessel A) and one containing 1000 ml of dimethyl dicarbonate without the addition of benzaldehyde (benzaldehyde content <0.001 ppm, Vessel B), are stored sealed for three months under the same conditions. Two 1.5-liter glass vessels with screw caps are used for storage. The storage temperature is 35°C. The purity of the dimethyl dicarbonate is then determined by gas chromatography.

[0047] Result: Dimethyl dicarbonate content vessel A: 99.93 wt.%, vessel B: 99.83 wt.% Example 4

[0048] Stability of the inventive mixture 2

[0049] Two vessels, one containing 1000 ml of Mixture 2 from Example 2 (Vessel A) and one containing 1000 ml of dimethyl dicarbonate without the addition of benzaldehyde (benzaldehyde content <0.001 ppm, Vessel B), are stored for three months under identical conditions. Two 1.5-liter glass vessels with screw caps and pressure relief valves are used for storage. The storage temperature is 38°C. The purity of the dimethyl dicarbonate is then determined by gas chromatography.

[0050] Result: Dimethyl dicarbonate content vessel A: 99.92 wt.%, vessel B: 99.82 wt.% Example 5

[0051] Microbiological efficiency of inventive dimethyl dicarbonate in beverage

[0052] Different germs were added at different concentrations to a mixture of 50 vol% apple juice / 50 vol% water. The initial germ count was determined without the active ingredient, with the inventive mixture from Example 1, and with dimethyl carbonate without additives. The results were recorded in 10 ml of matrix. The experiments were duplicated in each case. The results can be found in Table 1.

[0053] Results Killing value Asaia bogorensis

[0054] + = > 300 microbial units / ml_ “Number” = number of microbes / ml_ - = no microbes visible

[0055] Results Kill value Saccharomyces cerevisiae + = > 300 microbial units / ml_ “Number” = number of microbes / ml_ - = no microbes visible

[0056] The results demonstrate the improved efficacy of a mixture of 250 ppm dimethyl dicarbonate with 1 ppm benzaldehyde against Asaia bogorensis at a germination rate of 1 germ / ml to 100 germs / ml and against Saccaromyces cerevisiae at 100,000 germs / ml to 1,000,000 germs / ml, with at least the same efficacy being achieved at 1,000 germs / ml compared to dimethyl dicarbonate without benzaldehyde as a stabilizer.

[0057] Example 6

[0058] Stabilized beverages according to the invention

[0059] An apple spritzer from Adelholzener and a beer mix from Bitburger (double lemon) were opened non-sterile. After 60 minutes, 200 ppm of dimethyl dicarbonate from Example 1 was added to the drinks. The drinks were then hermetically resealed. The drinks were stored at 25 °C and were microbiologically stable for > 3 months. No changes in the taste or odor of the drinks were visible, and no carbon dioxide was released.

Claims

1 . Mixture containing at least one compound of formula (I) where R 1 and R 2 independently of one another represent straight-chain or branched Ci-C8-alkyl, cycloalkyl, C2-C8-alkenyl, C2-C8-alkynyl or benzyl, in an amount > 90 wt.%, and at least one compound of formula (II) where R 3 and R 4 independently of one another represent H, CI or straight-chain or branched Ci-C8-alkyl, in an amount of 1*10 -6 Wt% to 0.1 wt% based on the total weight of the mixture.

2. Mixtures according to claim 1, characterized in that R 1 and R 2 independently of one another represent straight-chain or branched Ci-Cs-alkyl, C8-alkenyl or benzyl.

3. Mixtures according to claim 1 or 2, characterized in that the compounds of formula (I) are dimethyl dicarbonate or diethyl dicarbonate or mixtures of these compounds.

4. Mixtures according to one of claims 1 to 3, characterized in that R 3 and R 4 independently represent straight-chain or branched Ci-C4 alkyl and H.

5. Mixtures according to one of claims 1 to 4, characterized in that the compound of formula (II) is benzaldehyde.

6. Mixtures according to one of claims 1 to 5, characterized in that at least 99.75 wt.% of the compounds of formula (I) and 1*10 -6 wt.% to 0.1 wt.% of compounds of formula (II) are contained.

7. Mixtures according to one of claims 1 to 6, characterized in that the mixture contains at least 99.75 wt.% of compounds of formula (I) and 1*10 -6 Wt.% up to 5*10 -4wt.% of the compounds of formula (II).

8. Mixtures according to one of claims 1 to 7, characterized in that the remainder of the mixture comprises methanol and dimethyl dicarbonate and optionally phosphoric acid.

9. A process for the preparation of the mixtures according to any one of claims 1 to 8, characterized in that the compound of formula (I) is initially introduced and the compound of formula (II) is added, preferably in metered amounts.

10. Uses of the mixtures according to any one of claims 1 to 8 for sterilizing and preserving foodstuffs and beverages against attack and / or decomposition by microorganisms.

11. Use according to claim 10, characterized in that sports drinks, fruit juice-containing soft drinks with juice contents of 0.1 to 99%, nectars, juices, wine, wine-containing drinks, beer mixes, vitamin drinks, isotonic drinks and energy drinks are treated.