DE19724605A1 - Preparation of hydrophilic, homogeneous, mono:glyceride formulation, - Google Patents

Abstract

Hydrophilic, homogeneous, monoglyceride formulation, which is obtained from a homogeneous mixture having a monoglyceride content of at least 40 wt.%, using a water-free liquid agent having good water solubility, based on polyols and/or polyethers, in a weight ratio of 1 : 0.1-1. Preferably the glyceride components may contain diglycerides and/or triglycerides. The glyceride components may contain esterified, saturated or unsaturated 12-24C fatty acids, which may be substituted by 1-3C alkyl and/or OH groups. The weight ratio of water-free formulated agent to monoglyceride is 0.3-0.7 : 1. The water-soluble agent may be a diol or triol e.g. ethylene glycol, propylene glycol, glycerine, polyethylene glycol (PEG), polyethylene glycol ester, polyethylene glycol ether, polysorbate (Tween), or mixtures thereof.

Description

The present invention relates to hydrophilic, homogeneous Monoglyceride formulations and a process for their preparation.

Monoglycerides (monoacylglycerides) belong to the fatty acids one of the most important emulsifiers worldwide, e.g. B. in the manufacture of Food, cosmetics and technical products in general. Because of their good environmental compatibility and toxicological They are accepted by legislators worldwide as safe. Monoglycerides are often used together with diglycerides and possibly Triglycerides used. Many commercial products are therefore Mixtures of partial glycerides with a monoglyceride content between 40 and 60% by weight. Products are used for special applications a content of monoglycerides greater than 90 wt .-% required. Dependent the unsaturated fatty acids of the Monoglycerides can also be hardened or, especially for cosmetic products, synthetic or natural only in small quantities occurring fatty acid residues, such as isostearate, are used by the the microbiological stability of the products is improved.

Mono- and diglycerides are now essentially two industrial processes: the esterification of Glycerin with fatty acids and the transesterification of triglycerides with Glycerin. Enzymatic process for the production of monoglycerides are still of little importance in terms of quantity. With the usual methods, glyceride mixtures with a Monoglyceride content up to a maximum of 60 wt .-% can be obtained. Products with a higher content of monoglycerides are technically complex either by molecular distillation in a high vacuum or by Gas extraction (EP 416 661 B1) accessible.

The emulsifying properties of the monoglycerides are due to the Determines the nature of the fatty acid residue, the short, medium or long chain, saturated, mono- or polyunsaturated as well as with alkyl or hydroxyl groups can be substituted. Especially if  Mixtures of different partial glycerides (mono-, di- and possibly Triglycerides) are used, the emulsion behavior changes in Dependence on the di- and possibly triglyceride proportions.

The use of monoglycerides is, however, in many applications limited due to their poor water dispersibility. Technologically therefore often have to be purified emulsifiers with better water solubility, like low-ester carbohydrates esterified with fatty acids Degree of esterification (e.g. mono-fatty acid esters of sucrose) or Alkyl polyglycosides are used. However, they are Manufacturing processes of these water-soluble emulsifiers usually expensive and consequently the costs for these products are correspondingly high. There is therefore great economic interest in being inexpensive Emulsifiers with good water dispersibility are available.

To improve the water dispersibility of mixtures of mono-, Di- and triglycerides, as they are typically from the technical Synthesis of transesterification of triglycerides with glycerin or the esterification of fatty acids with glycerin can occur Enrichment takes place via distillation methods or a gas extraction (DE-PS 41 18 487; EP-B 416 661). The products thus obtained with a Monoglyceride content greater than 90 wt .-% show a clear Improvement in their water dispersibility compared to the Source products. However, especially with longer chains saturated fatty acid residues, e.g. B. monostearate or monopalmitate Water wettability and thus the dispersibility in water only low and therefore their application options, especially in the Production of emulsions or suspensions in water, in particular limited at temperatures below 50 ° C. This is often tried to do so handle that small amounts of more water soluble Co-emulsifiers are added (surfactants in consumer products, J. Falbe (ed.), Springer Verlag, Berlin, 1987, p. 99). However, this also has Approach their practical limits in mutual solubility of the emulsifier systems produced. Although z. B. in the melt of Monoglycerides at elevated temperatures numerous hydrophilic Co-emulsifiers are soluble to a certain extent, but the  Formulation when cooling the melt by a fractional Crystal formation is inhomogeneous and the Degree of dispersity of the emulsifier system in the formulation.

It is also by means of numerous chemical modification processes possible, the emulsifying properties of the monoglycerides and their To specifically modify mixtures with diglycerides. For example industrially by reacting the monoglyceride (mixtures) with Acetic anhydride, lactic acid, citric acid, Tartaric acid / acetic anhydride or phosphoric acid with new derivatives modified surface-active properties, including the Solubility and dispersibility of the emulsifiers in water improved can be. However, due to the varied Reaction possibilities of the starting compounds complex composite products arise, which, for. B. not like the mono and Diglycerides of fatty acids generally as emulsifiers for Food are approved (LMBG, ZZulV from December 22, 1981 in the currently valid version).

Different emulsifiers with good ones are available as an alternative Dispersibility and solubility in water are available, such as esters of Fatty acids with sugars or low sugar alcohols Degree of esterification or alkyl polyglycosides, however, these are emulsifiers compared to the monoglycerides and their mixtures mostly clear higher in price.

The object of the present invention was therefore, on the one hand, hydrophilic, to provide homogeneous monoglyceride formulations at low cost, which both by themselves and in mixtures with diglycerides and / or Triglycerides in water significantly improved wettability and therefore Have dispersibility, and on the other hand a method for their Offer manufacture, the disadvantages of the previously known Products and procedures are overcome.  

The object of the invention was achieved with formulations that a homogeneous mixture consisting of a glyceride component at least 40 wt .-% of monoglycerides and an anhydrous liquid formulation auxiliaries with good water solubility on polyol and / or based on polyester in a weight ratio of 1: 0.01 to 1 contain on the monoglyceride portion of the glyceride component. According to the invention, the formulations are solidified Melts, which are characterized by their high degree of dispersity.

It was found that the dispersibility of monoglycerides in Water through the homogeneous admixture of the invention water-soluble formulation auxiliaries in the proportions mentioned can be significantly improved, with the surprising effect besides that in comparison to the inhomogeneous formulations with corresponding Composition significantly improved water dispersibility another is that the consistency of the formulations by the Addition of formulation aids is only slightly influenced. Thereby formulations can now be purified using the invention Monoglycerides, especially monopalmitate or monostearate, in solid Shape, such as B. as a powder or pellet, what above all from the practical point of view of use of great advantage is.

When using mixtures of monoglycerides with di- and / or Triglycerides become these for the formulations according to the invention a maximum of the same parts by weight of formulation auxiliaries added to the proportion of monoglycerides. A higher amount of Formulation tools would firstly ensure the homogeneity of the Unstabilize formulation and on the other hand to no further, decisive improvement in the dispersibility of the formulation in Water. In addition, a higher addition leads Formulation tools for an avoidable reduction in the proportion the actually emulsifying monoglycerides in the Formulation.  

Water-soluble, liquid formulation aids i.S. of this invention all polyols or polyethers, but preferably diols or triols, such as Ethylene glycol, propylene glycol, glycerin, polyethylene glycols (PEG) or Polyethylene glycol ester, polyethylene glycol ether or polysorbate (Tween) or any mixtures thereof. In particular, glycerin, which is due to its toxicological harmlessness for food, dietary and pharmaceutical products can be used is of special Interest, as it is also supported by lawmakers, e.g. B. in German food and Consumer Goods Act (LMBG) as an additive in addition to the mono and diglycerides is generally approved for food. In principle However, higher molecular weight, liquid formulation auxiliaries, which are common in the cosmetic and pharmaceutical industry, be used. It is essential to the invention in all cases that the Formulation aids for formulating in the most anhydrous form possible are used, the upper tolerance limit being 5% by weight of water are to be applied.

In principle, the weight ratio of formulation aids wettability to the monoglyceride components of the glyceride component and dispersibility of the formulations in water, depending on their Intended use, can be set specifically. Generally is a better one Water dispersibility of the formulation with a higher proportion To achieve formulation aids, being complete Dispersibility in cold water can be achieved. Will Monoglycerides in mixtures with other glycerides (di- and possibly Triglycerides) formulated according to the invention, the Wettability and dispersibility of the total glyceride mixture in Water significantly improved.

The consistency of the homogeneous formulations depends heavily on that of the Starting material. For example, distilled monoglycerides (Monoglyceride content greater than 90 wt .-%) of the saturated fatty acids an average chain length of more than 12 carbon atoms Room temperature fixed, also by the invention Formulation process a solid, especially powdery Product consistency can be achieved. Formulations according to the invention  of monoglycerides with unsaturated fatty acid residues, such as monooleate, show particularly good water dispersibility. Generally the Consistency of the formulations, such as from non-formulated ones Monoglyceride products are well known, with increasing number of Double bonds in the fatty acid residues softer, with Pasty products can be obtained at room temperature. From pasty However, consistency can also be formulations that are not made up of enriched monoglyceride fractions can be obtained, such as. B. Glyceride mixtures of lauric acid. The is of particular interest powdery consistency of the formulations according to the invention distilled monopalmitate, monostearate and monooleate, as these are among the Monoglycerides play an important quantitative role industrially.

Essential for achieving the outstanding properties of the Formulations is the production of a homogeneous and stable Mixture of the glyceride component and the anhydrous Formulation tools. According to the invention, these two Components in a suitable solvent as an extractant serves, brought together homogeneously, the process conditions so must be chosen that no segregation of the components in the Preparation of the formulation, such as. B. when cooling through fractional crystallization takes place.

Water-soluble formulation aids, such as. B. glycerin, are in molten monoglyceride (mixture) depending on their Composition, up to 20% by weight miscible in one phase. Will such mixtures but below the melting point of When the glyceride component has cooled, partial segregation takes place fractional crystallization processes take place, d. H. the system will inhomogeneous. If the quantitative addition of formulation aids is chosen higher for the Gylcerid melt, forms Two-phase system, in which one phase is rich and the other Phase is low in formulation aids. Understandably, in in this case in particular the formation of a homogeneous formulation difficult.  

A process in two steps has proven to be particularly suitable for the preparation of the formulations according to the invention: For this purpose, in process step a) the molten glyceride component with the anhydrous formulation aid is used in a weight ratio of 1: 0.1 to 1, based on the monoglyceride content the glyceride component at temperatures between 20 and 90 ° C, if necessary mixed with the addition of a suitable solvent so that you get macroscopically a single-phase system. Both distilled monoglyceride products and commercially available monoglyceride mixtures with different proportions of mono-, di- and optionally triglycerides can be used as starting materials. In any case, the monoglyceride content must be ≧ 40% by weight. Alcohols with chain lengths C ₁ to G ₅ , in particular methanol, ethanol and n- and i-propanol or mixtures thereof, have proven useful as solvents which ensure, inter alia, the pumpability of the mixture, in particular in the case of long-chain, saturated monoglycerides of high purity, such as monostearate. According to the process, the addition of solvent should always be limited to the minimum necessary. As a rule, the addition of solvent should not exceed 100% by weight, based on the glyceride component used.

The single-phase mixture obtained from process step a) is then subjected to the actual formulation process step in process step b), in which the solvent (mixture) which may also be present in the glyceride mixture and which also comprises diglycerides or triglycerides is removed. For this purpose, the single-phase mixture obtained according to a) with a C ₂ - to C ₄ -hydrocarbon, such as ethane, propane or butane or their mixtures as an extractant at a pressure between 40 and 500 bar and temperatures of 30 to 150 ° C. in a separation column extracted in such a way that the upper phase, which may contain C _1-5 alcohol and / or di- or triglyceride-rich top product, and the lower phase containing monoglyceride and formulation auxiliaries in the form of a melt are discharged as bottom product and the hydrophilic, homogeneous monoglyceride formulation is obtained from the bottom product as a melt.

With higher proportions of formulation aids, which without Solvent additive with the monoglyceride melt two-phase systems it is crucial for the procedure that (i) by the Solvent change in the extraction step the homogeneous formulation as Melt is formed, which (ii) in the column bottom under the conditions of the invention is stable, and that (iii) the formulation during discharge from the column and the spontaneous removal of the Extraction gas remains stable. In contrast to one conventional cooling of the melt, which inevitably leads to a fractional crystallization, the monoglyceride formulation leads as homogeneous product with a high degree of dispersity can be obtained, the Condition is best described with a solidified solution.

The extraction process is carried out in step b) in said column preferably carried out continuously in a countercurrent process, which is for the desired enrichment of the monoglyceride formu lation in the bottom product has proven to be advantageous if Hydrocarbon gas (mixture) as a further extraction agent up to 50 % By weight of trifluoromethane are added.

For improved separation of the mixtures in two phases (Upper phase / lower phase) is in a process variant in the column set a temperature gradient at which the head temperature is 5 to 30 ° C above that of the column bottom.

In order to extract the product from the extractant as a column bottom liberate, the inventive method provides that the melt is discharged from the column, in particular by Pressure reduction to normal pressure a spontaneous removal of the gaseous extractant (mixture) is largely sufficient. The Bottom product is then, for example, by further pressure reduction. by means of a vacuum pump and / or an increase in temperature from Extractant (mixture) freed. By discharge over a suitable Nozzle arrangement at ambient pressure can be the formulation especially in the presence of monopalmitate, monostearate and / or Monooleat, through the spontaneous cooling through the escaping  gaseous extractant (mixture) can be obtained as a powder, the if necessary by suitable mechanical methods, e.g. B. compacted into pellets can be.

Evaporation by lowering the pressure and / or increasing the temperature is also recommended for the separation of the extracting agent (mixture) of the top product, i.e. the fraction containing solvents if necessary. That so separated extractant can then be recompressed, before it is used again in the extraction process.

The obtained with the inventive method Monoglyceride formulations are within the scope of the present Invention due to its excellent wettability and Dispersibility in water preferably for the preparation of aqueous Emulsions and / or suspensions are suitable. Is of interest here especially the stabilization of oil-in-water emulsions, such as typical ones Creams.

The extraction process with compressed hydrocarbon gases is not used by the present invention to glycerol to remove from glycerides or pure mono-, di- or triglycerides to isolate from a glyceride mixture: With the present method on the contrary, the formulation tools such as Glycerin, homogeneous from the monoglyceride-containing glyceride component enclosed; an extraction takes place only in relation to the Solvent separation. The procedure therefore serves primarily the Obtaining the homogeneous formulations according to the invention consisting of monoglycerides and formulation aids as well as possibly their mixtures with di- and triglycerides. Because of the special Starting compounds and in combination with the Process conditions are therefore not pure mono-, di- and Triglycerides obtained from glyceride mixtures, but there will be Monoglyceride formulations with a significantly improved wetting and Maintain dispersibility in water.

The following examples are intended to illustrate preferred procedures Production of the new hydrophilic, homogeneous Clarify monoglyceride formulations.  

example 1

A distilled monostearate (content of monoglyceride <90 wt .-%) was melted at about 80 ° C and 25 wt .-% based on monostearate anhydrous glycerin stirred in so that there is a 2-phase system trained. After cooling to about 75 ° C., 10% by weight were based on Monostearate of ethanol (99.8%) added, whereby a stable, Macroscopic single-phase system was created.

This homogeneous mixture was the by means of a high pressure pump lower third of an extraction column (height: 2 m, inner diameter: 3 cm), which was filled with Sulzer wire mesh packings type CY, fed. Compressed propane was used as an extractant in one Pressure of 50 bar. The process temperature was at the inlet of the column approx. 90 ° C, 98 ° C in the column head and 87 ° C in the column bottom. The Ratio of the pumped mixture (feed) to the extractant (Propane) averaged 3.5% by weight (± 1% by weight). The The empty tube speed of the extraction gas in the column was 2 mm / s.

However, that which is discharged via the column head and loaded with ethanol almost glycerin and monoglyceride-free extractant was in one Separator evaporates at approx. 70 ° C and 8 bar, the ethanol was largely deposited. The one formed according to the procedure Formulation of monoglyceride and glycerin was at the bottom of the Extraction column via a nozzle arrangement at normal pressure carried out, with the spontaneous evaporation of the propane The formulation cooled and a free-flowing powder took place could be won. The glycerol content in the formulation was approx. 20% by weight.

An analysis of the bottom product obtained showed at continuous operation of the column a constant Product composition.  

Example 2

A distilled monostearate (content of monoglyceride <90 wt .-%) was melted at about 80 ° C and 50 wt .-% based on monostearate anhydrous glycerin stirred in so that there is a 2-phase system trained. After cooling to approx. 75 ° C., 13% by weight were based on Monostearate of ethanol (99.8%) added, whereby a stable, Macroscopic single-phase system was created.

This homogeneous mixture was the by means of a high pressure pump lower third of an extraction column (height: 2 m, inner diameter: 3 cm), which was filled with Sulzer wire mesh packings type CY, fed. Compressed propane was used as an extractant in one Pressure of 80 bar. The process temperature was at the inlet of the column approx. 93 ° C, in the column head 100 ° C and in the column bottom 90 ° C. The Ratio of the pumped mixture (feed) to the extractant (Propane) averaged 4.2% by weight (± 1% by weight). The The empty tube speed of the extraction gas in the column was 2 mm / s.

However, that which is discharged via the column head and loaded with ethanol almost glycerin and monoglyceride-free extractant was in one Separator evaporates at approx. 70 ° C and 8 bar, the ethanol was largely deposited. The one formed according to the procedure Formulation of monoglyceride and glycerin was at the bottom of the Extraction column via a nozzle arrangement at normal pressure carried out, with the spontaneous evaporation of the propane Cooling of the formulation took place and a free-flowing powder could be won. The glycerol content in the formulation was approx. 33% by weight.

The formulation obtained shows good dispersibility in cold Water.  

Example 3

A distilled monostearate (content of monoglyceride <90 wt .-%) was melted at about 80 ° C and 77 wt .-% based on monostearate anhydrous glycerin stirred in so that there is a 2-phase system trained. After cooling to about 55 ° C., 10% by weight were based on Monostearate of ethanol (99.8%) added, whereby a stable, Macroscopic single-phase system was created.

This homogeneous mixture was the by means of a high pressure pump lower third of an extraction column (height: 2 m, inner diameter: 3 cm), which was filled with Sulzer wire mesh packings type CY, fed. Compressed propane with a Proportion of 10% by weight of butane at a pressure of 50 bar. At the inlet of the Column, the process temperature was about 90 ° C, 97 ° C in the column head and in the column bottom 86 ° C. The ratio of the mixture pumped in (Feed) to the extractant (propane) averaged 4.2% by weight (± 1% by weight). The empty pipe velocity of the extraction gas in the Column was 2 mm / s.

However, that which is discharged via the column head and loaded with ethanol was almost glycerol and monoglyceride-free extractant mixture evaporated in a separator at about 70 ° C and 8 bar, the ethanol was largely deposited. The one formed according to the procedure Formulation of monoglyceride and glycerin was at the bottom of the Extraction column via a nozzle arrangement at normal pressure carried out, the spontaneous evaporation of the Propane / butane mixture took place a cooling of the formulation and a free-flowing powder was obtained. The glycerin content in the Formulation was approximately 43% by weight.  

Example 4

A distilled monostearate (content of monoglyceride <90 wt .-%) was melted at about 80 ° C and 100 wt .-% based on monostearate anhydrous glycerin stirred in so that there is a 2-phase system trained. After cooling to about 55 ° C., 10% by weight were based on Monostearate of ethanol (99.8%) added, whereby a stable, Macroscopic single-phase system was created.

This homogeneous mixture was the by means of a high pressure pump lower third of an extraction column (height: 2 m, inner diameter: 3 cm), which was filled with Sulzer wire mesh packings type CY, fed. Compressed propane was used as an extractant in one Pressure of 50 bar. The process temperature was at the inlet of the column approx. 90 ° C, 97 ° C in the column head and 86 ° C in the column bottom. The Ratio of the pumped mixture (feed) to the extractant (Propane) averaged 6.0% by weight (± 1% by weight). The The empty tube speed of the extraction gas in the column was 2 mm / s.

However, that which is discharged via the column head and loaded with ethanol almost glycerin and monoglyceride-free extractant was in one Separator evaporates at approx. 70 ° C and 8 bar, the ethanol was largely deposited. The one formed according to the procedure Formulation of monoglyceride and glycerin was at the bottom of the Extraction column via a nozzle arrangement at normal pressure carried out, with the spontaneous evaporation of the propane The formulation cooled and a powder was obtained could. The glycerol content in the formulation was approximately 50% by weight.

Claims (14)

1. Hydrophilic, homogeneous monoglyceride formulations, characterized in that they are a homogeneous mixture consisting of a glyceride component with at least 40% by weight of monoglycerides and an anhydrous liquid formulation aid with good water solubility on a polyol and / or polyether basis in a weight ratio of 1: 0.1 to 1 based on the monoglyceride content of the glyceride component. 2. Monoglyceride formulations according to claim 1, characterized characterized in that the glyceride component is di- and / or Contains triglycerides. 3. monoglyceride formulations according to claims 1 and 2, characterized in that the glyceride component contains esterified, saturated or unsaturated C _12-24 fatty acids which can be substituted with G _1-3 alkyl radicals and / or hydroxyl groups . 4. monoglyceride formulations according to claims 1 to 3, characterized characterized in that it contains the water-free formulation aid Weight ratio of 0.3 to 0.7: 1 based on the Monoglyceride content included. 5. monoglyceride formulations according to claims 1 to 4, characterized characterized as being a water-soluble formulation aid one from the series of diols or triols such as ethylene glycol, Propylene glycol, glycerin, polyethylene glycols (PEG), Polyethylene glycol esters, polyethylene glycol ethers and polysorbates (Tween) or mixtures thereof. 6. A process for the preparation of the water-dispersible, homogeneous monoglyceride formulations according to claims 1 to 5, characterized in that

• a) the melted glyceride component with the anhydrous formulation aid in a weight ratio of 1: 0.1 to 1 based on the monoglyceride content of the glyceride component at temperatures between 20 and 90 ° C, optionally with the addition of max. 100% by weight, based on the glyceride component of a C _1-5 alcohol, is mixed so that a single-phase system is obtained macroscopically, and
• b) the single-phase mixture obtained according to a) with a C ₂ - to C ₄ hydrocarbon or mixtures thereof as an extractant at a pressure between 40 and 500 bar and temperatures of 30 to 150 ° C is extracted in a separation column so that the C. _1-5 alcohol-containing and / or di- or triglyceride-rich upper phase as top product and the lower phase containing monoglyceride and formulation auxiliaries are discharged as bottom product and the hydrophilic, homogeneous monoglyceride formulation is obtained from the bottom product as a melt becomes.

7. The method according to claim 6, characterized in that as alcohol in process step a) methanol, ethanol and n- and i-propanol or Mixtures of these are used. 8. The method according to claims 6 and 7, characterized in that in process step b) the extractants (mixtures) with up to 50% by weight of trifluoromethane can be used. 9. The method according to claims 6 to 8, characterized in that the extraction in the column continuously in one Counterflow process is carried out. 10. The method according to claims 6 to 9, characterized in that in the separation column a temperature gradient in the manner is set that the head temperature 6 to 30 ° C above that of Column swamp lies.   11. The method according to claims 6 to 10, characterized in that the bottom product by lowering the pressure and / or Extractant (mixture) is freed from an increase in temperature. 12. The method according to claims 6 to 11, characterized in that the overhead product in a separator by lowering the pressure and / or temperature increase of the extractant (mixture) is liberated. 13. The method according to claims 6 to 12, characterized in that the separated extractant (mixture) recompresses and / or condensed and possibly recycled. 14. Use of the monoglyceride formulations according to the Claims 1 to 5 for the preparation of aqueous emulsions and / or suspensions.