Hydroxycarboxylic acid esters, process for their preparation and their use
阅读说明：本技术 羟基羧酸酯，其制备方法及其用途 (Hydroxycarboxylic acid esters, process for their preparation and their use ) 是由 R·莫尔施豪瑟 S·基里德 J·普鲁申 B·库瑟 于 2020-08-19 设计创作，主要内容包括：羟基羧酸酯,其制备方法及其用途。公开了式(I)的化合物：(R~1OOC)_a-R~2(OH)_c-COO-(C_nH_(2n)-O)_m-OC-R~3(OH)_d-(COOR~4)_b (I)；其中R~1和R~4彼此独立地为氢,金属阳离子,铵阳离子,C_1-C_6-烷基,具有3-9个环碳原子的环烷基,具有5-10个环碳原子的芳基,被1或2个烷基取代的芳基,借助亚烷基与羧基相连的芳基,-(C_nH_(2n-)O)_m-H或-O-R~2(COOR1)_(a+1),R~2和R~3彼此独立地为具有1-8个碳原子的脂族烃基,a和b彼此独立地为1至4的整数,c是整数0至4,d是整数1至4,n为2,3或4,和m为1,2,3或4,条件是R~1和R~4可以在给定定义的分子内不同。这些化合物的特征在于对金属阳离子非常良好的络合能力,且可在洗涤剂和清洁剂中,在油提取中使用并用于水软化。(Hydroxycarboxylic acid esters, a process for their preparation and their use. Disclosed are compounds of formula (I): (R) 1 OOC) a ‑R 2 (OH) c ‑COO‑(C n H 2n ‑O) m ‑OC‑R 3 (OH) d ‑(COOR 4 ) b (I) (ii) a Wherein R is 1 And R 4 Independently of each otherIs hydrogen, a metal cation, an ammonium cation, C 1 ‑C 6 -alkyl, cycloalkyl having 3 to 9 ring carbon atoms, aryl having 5 to 10 ring carbon atoms, aryl substituted by 1 or 2 alkyl, aryl linked to the carboxyl group by means of an alkylene group, - (C) n H 2n‑ O) m -H or-O-R 2 (COOR1) a+1 ，R 2 And R 3 Independently of one another, is an aliphatic hydrocarbon radical having 1 to 8 carbon atoms, a and b, independently of one another, are integers from 1 to 4, c is an integer from 0 to 4, d is an integer from 1 to 4, n is 2,3 or 4, and m is 1,2, 3 or 4, with the proviso that R 1 And R 4 May differ within a given defined molecule. These compounds are characterized by very good complexing power for metal cations and can be used in detergents and cleaners, in oil extraction and for water softening.)
1. A compound of formula (I):
(R1OOC)a-R2(OH)c-COO-(CnH2n-O)m-OC-R3(OH)d(COOR4)b (I)
wherein R is1And R4Independently of one another, hydrogen, metal cations, ammonium cations, C1-C6-alkyl, cycloalkyl having 3 to 9 ring carbon atoms, aryl having 5 to 10 ring carbon atoms, aryl substituted by 1 or 2 alkyl, aryl linked to the carboxyl group by means of an alkylene group, - (C)nH2n-O)m-H or-O-R2(COOR1)a+1，
R2And R3Independently of one another, are aliphatic hydrocarbon radicals having 1 to 8 carbon atoms,
a and b are independently an integer of 1 to 4,
c is an integer of 0 to 4,
d is an integer of 1 to 4,
n is 2,3 or 4, and
m is 1,2, 3 or 4, provided that R1And R4May differ within a given defined molecule.
2. Compounds of formula (I) according to claim 1, characterized in that n is 2 or 3 and m is 1 or 2.
3. Compounds of formula (I) according to claim 2, characterized in that n is 2 and m is 1.
4. Compounds of formula (I) according to at least one of claims 1 to 3, characterized in that c and d are 1.
5. Compounds of the formula (I) according to at least one of claims 1 to 4, characterized in that R2Is of the formula-CoH2oA divalent residue of (A) or of the formula-CpH2p-1<Or a trivalent residue of the formula>CqH2q-2<The tetravalent residue of (a),
where o is an integer from 2 to 4, preferably from 2 to 3, and particularly preferably 2,
p is an integer of 1 to 4, preferably 1 to 3, and more preferably 1 or 2, and
q is an integer of 2 to 4, preferably 2 to 3, and more preferably 3.
6. Compounds of the formula (I) according to at least one of claims 1 to 5, characterized in that R2And R3Is a residue derived from malic acid, lactic acid, tartronic acid, tartaric acid, isocitric acid, citric acid, acetylcitric acid, tartraric acid or mucic acid after removal of the carboxyl and hydroxyl groups.
7. Compounds of formula (I) according to claim 6, characterized in that R2And R3Is a residue of formula (Ib), (Ic), (Id), (Ie), (If) or (Ig):
8. compounds of formula (I) according to claim 6, characterized in that R2And R3Is a residue derived from citric acid after removal of carboxyl and hydroxyl groups.
9. Compounds of the formula (I) according to at least one of claims 1 to 8, characterized in that a and b are 2, R2And R3Is an aliphatic hydrocarbon group having 3 carbon atoms, and R1And R4Is hydrogen, an alkali metal cation, an alkaline earth metal cation, a quaternary ammonium cation, or of the formula — (C)nH2n-O)m-residues of H.
10. Compounds of the formula (I) according to at least one of claims 1 to 9, characterized in that the compounds have the structure of the formula (II) or their alkali metal or alkaline earth metal salts or partial neutralizers:
HO-C(CH2-COOH)2-COO-C2H4-OOC-COH-(CH2COOH)2 (II)。
11. compounds of the formula (I) according to at least one of claims 1 to 10, characterized in that these are present in the form of a mixture of several compounds of the formula (I) which are liquid at 25 ℃.
12. Compounds of the formula (I) according to at least one of claims 1 to 11, characterized in that these have the formula (R)1OOC)a-R2(OH) COO-and a radical of formula (R)4OOC)b-R3(OH) COO-, wherein these residues have the same meaning.
13. Process for the preparation of compounds of formula (I) according to at least one of claims 1 to 12 by the preparation steps:
(i) providing a hydroxycarboxylic acid of formula (V) or an ester-forming derivative thereof, optionally a carboxylic acid of formula (IV) or a hydroxycarboxylic acid or an ester-forming derivative thereof, and an alkylene glycol of formula (VI),
(R1OOC)a-R2(OH)c-COOR1 (IV)
R4OOC-R3(OH)d(COOR4)b (V)
OH-(CnH2n-O)m-H (VI)
wherein R is1，R2，R3，R4A, b, c, d, n and m have the meanings defined in claim 1,
(ii) (ii) heating the mixture obtained in step (i) to at least 90 ℃ over a period of time of from 0.1ms to 60 minutes, and
(iii) (iii) cooling the product mixture obtained in step (ii) to 25 ℃ or less over a period of 1s to 60 minutes.
14. The method according to claim 13, characterized in that the heating in step ii) is performed by irradiation with microwave radiation.
15. The process according to at least one of claims 13 to 14, characterized in that the mixture in step ii) is heated to a temperature of 140 to 160 ℃ and for a period of 1 to 120 seconds.
16. Use of a compound of the formula (I) according to at least one of claims 1 to 12 as complexing agent for metal cations, in particular alkaline earth metal cations.
17. Use of compounds of the formula (I) according to at least one of claims 1 to 12 as complexing agents in detergents and cleaning agents, in oil extraction or for water softening.
18. A washing and cleaning agent containing a compound of the formula (I) according to at least one of claims 1 to 12.
19. Washing and cleaning agent according to claim 18, characterized in that it is an agent for cleaning dishes.
Technical Field
The present invention relates to novel hydroxycarboxylic acid esters derived from aliphatic hydroxycarboxylic acids and from alkylene glycols. These compounds are excellent complexing agents and can be used in a wide variety of fields, for example in detergents and cleaners, in oil extraction or water softening.
Background
Polymeric hydroxycarboxylic acid esters, such as polymeric citric acid esters, are known from the literature and can be prepared by condensation reactions of hydroxycarboxylic acids with mono-or polyvalent alcohols. By heating the starting components, an esterification reaction is carried out, in which usually oligomers or polymers with undefined chain lengths are formed. There is also a risk of decomposition of the hydroxycarboxylic acid during the reaction, so that uncontrolled by-products are formed which themselves react with the components of the reaction mixture. For example, citric acid is easily decomposed at its melting point and loses COOH groups and thus it is difficult to obtain polyesters with reproducible chain lengths.
According to WO 2001/000463A 2, processes for the production of aliphatic carboxylic acid esters are known. In this process, the reaction mixture of an aliphatic carboxylic acid and a mono-or polyvalent alcohol is heated to a very high temperature, well above 100 ℃, by means of microwave irradiation for a very short time. The process provides almost quantitative yields with virtually no by-product formation. Citric acid is mentioned as an example of an aliphatic carboxylic acid.
CN 109293505 describes a process for converting lemon juice and hydrochloric acid under the influence of microwave radiation. In this document, it is stated that glycol citrate is produced by this method. However, this document does not disclose the presence of ethylene glycol during the conversion process, and the timing and manner of introduction of ethylene glycol into the reaction mixture. Additionally, the acidified lemon juice is exposed to microwave radiation for greater than 1 hour in a closed container. Under such conditions, the reactants are believed to partially decompose or polymerize.
According to WO 2019/158409 a1, methods for producing surface-active condensates of citric acid are known. The resulting product has at least one hydrophobic structural element which represents a hydrocarbon radical having at least 8 carbon atoms.
For many applications, polymerized citric acid is already known in the literature.
Yuzeng Zao et al, desalinization, Vol.392, pp.1-7 (2016) ((R))https:// www.sciencedirect.com/science/article/pii/S0011916416301813) By using poly (citric acid) derivatives, the formation of calcium sulfate deposits is inhibited. The products used have a high degree of polymerization and a large number of citric acid units.
A.T. Naeini et al, Nanomedicine,6(4), page 556-562 (2010), disclose copolymers of poly (citric acid) and poly (ethylene glycol) blocks as biocompatible hybrid materials for Nanomedicine.
Memarizadh et al describe linear dentate copolymers and indoxacarb as supramolecular systems for biodegradable and effective nanoinsecticides in Environmental Science: Processes & Impacts,2014,16, 2380-. As the copolymer, a toothed block copolymer of polyethylene glycol and poly citric acid was used.
D.Gyawaii et al describe in situ curable and biodegradable polymers for the production of cell cultures, in Biomaterials 31(34), pages 9092-2108 (2010). The proposed polymers are derived from polyethylene glycol, maleic acid and citric acid and tend to form hydrogels.
An analytical method for characterizing poly (glycerol citrate) foams, which are produced by the action of microwave radiation, is described by Tissert et al in J.Polym.Environ (2012),20: 291-298. In the production of this polymer, equimolar amounts of citric acid and glycerol are used, resulting in a polymer with a high molecular weight.
Tissert et al describe the synthesis of polyesters derived from citric acid and glycerol in J.of Applied Polymer Science, Vol.125,3429-3437 (2012). To produce polyester, starting materials are provided in varying proportions and then heated using various heating methods, including microwave irradiation. Depending on the heating method used and the ratio of the starting materials, different products are obtained which aggregate in the form of foams, gels or liquids.
WO 92/16493 a1 describes polyhydroxy compounds having at least three hydroxyl groups, such as polyglycerols or citric acid esters of sugar alcohols, and their use in detergents and cleaning agents. The compounds can enhance the effectiveness of other detergent additives.
According to DE 1,617,122A, water-soluble salts of polyesters containing free carboxyl groups are known, the acid component of which consists of tri-or tetracarboxylic acid residues and the alcohol component of which is derived from compounds having two aliphatic hydroxyl groups. For example, polyesters derived from citric acid and ethylene glycol are described. These are high molecular weight resins that dissolve in the alkaline wash. These agents facilitate the washing process and increase the whiteness of the laundry.
Thus, according to the prior art, esters of aliphatic hydroxycarboxylic acids and various alcohols are known, for example polyesters derived from citric acid and glycerol or other polyols. Molecules with different chain lengths have also been described which may include, for example, citric acid in two units up to more than 100 acid units.
To prepare esters of aliphatic hydroxycarboxylic acids, condensation reactions are carried out in various solvents, for example in water, glycerol, propylene glycol and ethylene glycol. It has surprisingly been found that esters prepared from hydroxycarboxylic acids and alkylene glycols or polyalkylene glycols of low degree of condensation are excellent as complexing agents for different cations by exposure to high temperature pulses. For example, esters derived from ethylene glycol and citric acid which have few citric acid units in total show excellent complexing tendencies, whereas esters derived from glycerol and citric acid which also have few citric acid units in total do not have a tendency to complex formation.
Disclosure of Invention
It is an object of the present invention to provide compounds which are derived from readily available starting materials, preferably starting materials of biological origin, and which have an excellent tendency to form complexes.
The present invention relates to compounds of the following formula (I):
(R1OOC)a-R2(OH)c-COO-(CnH2n-O)m-OC-R3(OH)d(COOR4)b (I)
wherein R is1And R4Independently of one another, hydrogen, metal cations, ammonium cations, C1-C6-alkyl, cycloalkyl having 3 to 9 ring carbon atoms, aryl having 5 to 10 ring carbon atoms, aryl substituted by 1 or 2 alkyl, aryl linked to the carboxyl group by means of an alkylene group, - (C)nH2n-O)m-H or-O-R2(COOR1)a+1，
R2And R3Independently of one another, are aliphatic hydrocarbon radicals having 1 to 8, preferably 2 to 4, carbon atoms,
a and b are each independently of the other an integer from 1 to 4, preferably from 1 to 3,
c is an integer from 0 to 4, preferably from 1 to 4, especially 1 or 2, and most preferably 1,
d is an integer from 1 to 4, preferably 1 or 2, and most preferably 1,
n is 2,3 or 4, preferably 2 or 3, and especially 2, and
m is 1,2, 3 or 4, provided that R1And R4May differ within a given defined molecule.
The compound of formula (I) may also be represented by the following formula (Ia):
wherein R is1，R2，R3，R4A, b, c, d, m and n have the meanings defined above.
By NMR analysis it can be concluded that in the condensation reaction mediated by pulsed temperature rise, e.g. by microwave radiation, molecules with some hydroxycarboxylic acids, e.g. molecules with 2 or 3 citric acid units, are formed. Hydroxycarboxylic acid units, for example citric acid units, are bonded via ester bonds to units derived from alkylene glycols or from di-to trialkylene glycols used as solvents. This results in low molecular weight compounds and not in polymers.
Hydroxycarboxylic acids exhibit, when reacted with alcohols other than (poly) alkylene glycols, very high solution viscosities or browning, for example in the reaction with glycerol, and, in addition, the resulting products exhibit no or only a low tendency to complex.
Polyesters containing a large number of hydroxycarboxylic acid units and alcohol units often have too high a viscosity and are therefore not free-flowing and non-pumpable. These products are typically produced by heating using conventional sources and are not suitable as complexing agents.
The compounds of the formula (I) according to the invention are frequently present in liquid form, in particular in the form of clear liquids having a viscosity of at least 100mPas at 25 ℃ as measured with a rotational viscometer (Brookfield viscometer).
The compounds of formula (I) according to the invention are generally obtained as mixtures of substances. Preferred mixtures of materials derived from citric acid and ethylene glycol contain, for example, ethylene glycol dicitrate of the formula:
this ester is very suitable for complexing with metal ions, in particular with alkaline earth metal ions. The complexes with calcium are shown below:
however, other citric acid esters are also present in the mixture, e.g. having free carboxyl groups instead of the glycol ester group-COO-CH2-CH2-OH, or compounds in which further citric acid units are bonded to the hydroxyl groups of the alkylene glycol via their carboxyl groups.
In addition, the mixture may also contain small proportions of unreacted starting materials, for example free diols and/or hydroxycarboxylic acids or optionally carboxylic acids.
Mixtures containing different polyesters of the formula (I) are generally liquid at 25 ℃. The viscosity of these mixtures at 20 ℃ is preferably from 0.1 to 10,000 mPas, preferably from 1 to 7500 mPas, and particularly preferably from 100 to 2000mPas, measured with a Brookfield viscometer (spindle 1 to 7, depending on the viscosity range; shear speed 5 rpm).
The polyesters of the present invention are prepared by reacting aliphatic hydroxycarboxylic acids with selected aliphatic (poly) alkylene glycols. The aliphatic (poly) alkylene glycol is an alkylene glycol having 2,3 or 4 carbon atoms, or a polyalkylene glycol having 2,3 or 4 repeating alkylene glycol units. These compounds generally have the following structure:
HO-(CnH2n-O)m-H
wherein n and m have the meaning defined above.
Preferably, ethylene glycol or propylene glycol is used, i.e. a compound of the above formula wherein n is 2 or 3.
Particularly preferred (poly) glycols, i.e. compounds of the above formula wherein n is 2, are used.
Particularly preferred ethylene glycols or diethylene glycols, i.e. compounds of the above formula in which n is 2 and m is 1 or 2, are used.
Very preferred glycols, i.e. compounds of the above formula wherein n is 2 and m is 1, are used.
Preference is given to compounds of the formula (I) in which n is 2 or 3 and m is 1 or 2. These compounds are derived from ethylene glycol, propylene glycol, diethylene glycol or dipropylene glycol.
Particular preference is given to compounds of the formula (I) in which n is 2 and m is 1. These compounds are derived from ethylene glycol.
The aliphatic hydroxycarboxylic acids used in the preparation of the compounds of formula (I) according to the invention include any type. These may be aliphatic hydroxycarboxylic acids having 2,3 or 4 or 5 carboxyl groups. The aliphatic hydroxycarboxylic acid may have 1 to 4 hydroxyl groups. The hydroxyl group may be located on a common carbon atom with the carboxyl group, or the hydroxyl group may be in an alpha, beta, or other position relative to the carboxyl group. The carboxyl groups are typically located on different carbon atoms of the aliphatic residue. If several hydroxyl groups are present, they are located on different carbon atoms of the aliphatic residue. Aliphatic residues generally have from 1 to 8, preferably from 2 to 4, carbon atoms.
Preferably, the compounds of formula (I) are derived from malic acid, lactic acid, tartronic acid, tartaric acid, isocitric acid, citric acid, acetylcitric acid, tartaric acid or mucic acid, in particular from isocitric acid or citric acid, and very preferably from citric acid.
In the preparation of the compounds of the formula (I), aliphatic hydroxycarboxylic acids may optionally also be combined with aliphatic carboxylic acids. Instead of aliphatic hydroxycarboxylic acids or aliphatic carboxylic acids, use may also be made of their ester-forming derivatives, such as esters, anhydrides, halides or salts thereof.
Preferably, in the preparation of the compounds of formula (I), only one or more aliphatic hydroxycarboxylic acids and/or their reactive derivatives and/or their salts are used.
The carboxylic acids optionally used in the preparation of the compounds of formula (I) according to the invention include any type. These may be aliphatic carboxylic acids having 2,3 or 4 or 5 carboxyl groups. The carboxyl groups are typically located on different carbon atoms of the aliphatic residue. Aliphatic residues generally have from 1 to 8, preferably from 2 to 4, carbon atoms.
Examples of aliphatic carboxylic acids are oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, carbonic acid (carbonic acid), butane-1, 2, 4-tricarboxylic acid or octanoic acid (octric acid). In the preparation of the compounds of the formula (I), different aliphatic carboxylic acids can be used in combination with the aliphatic hydroxycarboxylic acids or with derivatives of the aliphatic hydroxycarboxylic acids, for example their esters or their salts.
Residue R1And R4May refer to an alkyl group. These are alkyl groups having 1 to 6 carbon atoms, which may be straight-chain or branched. Methyl and ethyl are preferred.
Residue R1And R4May refer to cycloalkyl. These are cycloalkyl radicals having 3 to 9 ring carbon atoms, preferably 5 to 7 ring carbon atoms. Cyclohexyl is particularly preferred.
Residue R1And R4May refer to an aryl group. These are aromatic hydrocarbon residues having 5 to 10 ring carbon atoms. Phenyl is preferred.
Residue R1And R4May refer to an alkaryl group. These are aryl groups substituted by 1 or 2 alkyl groups. Tolyl groups are preferred.
Residue R1And R4May refer to an aralkyl group. These are aryl groups linked to the carboxyl group via an alkylene group. Benzyl is preferred.
Preferred radicals R1And R4Is hydrogen, a metal cation, an ammonium cation or of the formula- (C)nH2n-O)m-residues of H.
In particular, the residue R1And R4Is hydrogen, an alkali metal cation, an alkaline earth metal cation, a quaternary ammonium cation or of formula- (C)nH2n-O)mA residue of-H, in particular of formula-C2H4-the residue of OH.
Residue R2And R3Is an aliphatic hydrocarbon group having 1 to 8, preferably 2 to 4, carbon atoms. R2And R3And may be straight chain or branched. Residue R2And thus the number of covalent bonds connecting this residue to other groups in the molecule is a + c + 1. Depending on the size of the indices a and c, R2The valence of (a) may thus be from 2 to 9. Residue R3Is b + d + 1. Thus, depending on the size of the indices b and d, R3The valence of (a) may be 3 to 9. Not all of the commonly possible residues R2Or R3May have a valence in the range of 2 to 9 or in the range of 3 to 9, since the number of possible free valences may be smaller in the individual case due to the tetravalent carbon atom. Residues R having, for example, only 1 carbon atom2And thus may have only a value in the range of 2 to 4. Those skilled in the art will recognize the contents of this context.
Preferably of formula-CoH2oA divalent residue of (A) to (B)2Or has the formula-CpH2p-1<Of a trivalent residue R2Or has the chemical formula>CqH2q-2<A tetravalent residue R of2Wherein o is an integer of 2 to 4, preferably 2 to 3, and particularly preferably 2, and p is an integer of 1 to 4, preferably 1 to 3, and more preferably 1Or 2, and q is an integer from 2 to 4, preferably from 2 to 3, and more preferably 3.
Especially preferred are compounds of formula (I) wherein R2And R3Is a residue derived from malic, lactic, tartronic, tartaric, isocitric or citric acid after removal of the carboxyl and hydroxyl groups.
These particularly preferred residues R2And R3Having the structure of formula (Ib), (Ic), (Id), (Ie), (If) or (Ig):
particularly preferred are compounds of formula (I) wherein a and b are 2, R2And R3Is an aliphatic hydrocarbon radical having 3 carbon atoms, in particular an aliphatic hydrocarbon radical residue derived from citric acid, and R1And R4Is hydrogen, an alkali metal cation, an alkaline earth metal cation, a quaternary ammonium cation or of formula- (C)nH2n-O)m-residues of H.
Especially preferred are compounds of formula (II) below or alkali metal or alkaline earth metal salts or partial neutralizers thereof (neutralisates).
HO-C(CH2-COOH)2-COO-C2H4-OOC-COH-(CH2COOH)2 (II)。
The compounds of formula (II) may also be represented by formula (IIa):
furthermore, mixtures comprising different compounds of the formula (I) which are liquid at 25 ℃ are particularly preferred.
Further, it is also preferable to have the formula (R)1OOC)a-R2(OH) -COO-and residues of formula (R)4OOC)b-R3(OH) COO-, wherein these residues have the same meaning.
The compounds of formula (I) can be prepared by esterification of aliphatic hydroxycarboxylic acids or their ester-forming derivatives, e.g. their alkyl esters, with selected diols at elevated temperatures, wherein the temperature rise in the reaction mixture must be pulsed, but the temperature controlled. Under these conditions, only small molecules are formed and no polymerization or decomposition of the components used takes place. Optionally, the reaction mixture may additionally contain aliphatic carboxylic acids or their ester-forming derivatives.
The invention therefore also relates to a process for preparing compounds of the formula (I) by the following measures:
(i) providing a hydroxycarboxylic acid of formula (V) or an ester-forming derivative thereof, such as an alkyl ester thereof, and optionally a carboxylic acid or hydroxycarboxylic acid of formula (IV) or an ester-forming derivative thereof, such as an alkyl ester thereof, and an alkylene glycol of formula (VI),
(R1OOC)a-R2(OH)c-COOR1 (IV)
R4OOC-R3(OH)d(COOR4)b (V)
OH-(CnH2n-O)m-H (VI)
wherein R is1，R2，R3，R4A, b, c, d, n and m have the meanings defined above,
(ii) (ii) heating the mixture obtained in step (i) to at least 90 ℃ over a period of time of from 0.1ms to 60 minutes, and
(iii) (iii) cooling the product mixture obtained in step (ii) to 25 ℃ or less over a period of 1s to 60 minutes.
The required supply of thermal energy can be performed by any means that can briefly input high amounts of thermal energy into the reaction mixture. It is important to limit the reaction temperature to this value in such a way as to avoid decomposition of the reactants. Examples of suitable devices are heat exchangers, in particular recuperators, or electromagnetic radiation in the microwave band.
Known types can be used as the recuperator. Examples of these are plate heat exchangers, capillary heat exchangers, microreactors, spiral tube heat exchangers, tube bundle heat exchangers, U-tube heat exchangers, jacketed tube heat exchangers, heat recorders or counterflow heat exchangers.
Preferably, the reaction mixture is fed in a heating zone by high thermal energy heated by electromagnetic radiation in a microwave band or by a heat exchanger.
It is particularly preferred to design the heating zone in the form of a pressure-resistant, microwave-transparent tube, which is located in a cavity resonator of suitable dimensions, and which is capable of generating an electromagnetic field, preferably in the microwave band, an electromagnetic field of suitable field strength, with the aid of which the reaction material is heated by means of a dielectric heating device.
The electromagnetic radiation used preferably has a frequency in the range from 300MHz to 30GHz, in particular 915MHz, 2.45GHz or 5.8 GHz.
Since the reaction mixture is exposed to high temperatures for a short period of time, esterification and transesterification reactions take place very rapidly and simultaneously in this mixture. In this case, the majority of the hydroxycarboxylic acids and diols present are esterified, wherein in the case of hydroxycarboxylic acids having several carboxyl groups, frequently a portion of the carboxyl groups remains unesterified.
Preferred is a method in which the heating in step (ii) is carried out by irradiating microwave radiation.
The reaction temperature in step (ii) is generally in the range of from 90 to 190 ℃, preferably from 120 to 180 ℃, and most preferably from 140 to 160 ℃.
Especially preferred is a process wherein the mixture in step (ii) is heated to a temperature of 140 to 160 ℃ and wherein the period of heating is 1 to 120 seconds.
The process according to the invention can be carried out batchwise or preferably continuously.
In the practice of the process of the present invention, the alkylene glycol is preferably used in a molar excess relative to the hydroxycarboxylic acid.
The molar ratio of hydroxycarboxylic acid to alkylene glycol is generally from 1:10 to 10:1, preferably from 5:1 to 1:5 and particularly preferably from 1:1 to 1: 3.
The process of the invention can be carried out in different reaction mixtures. Examples are emulsions or solutions. Preferably, the process of the invention is carried out in solution. In the process of the present invention, the reaction mixture according to process step i) contains compounds of the formula (V) and optionally of the formula (IV) or their ester-forming derivatives, and compounds of the formula (VI).
As solvents, all liquids are possible in which the reactants are dissolved and which are substantially inert under the reaction conditions. Examples thereof are aprotic polar organic solvents.
In a preferred embodiment, the alkylene glycol used simultaneously acts as solvent for the resulting oligoester.
The process of the present invention is carried out with or without the use of an esterification or transesterification catalyst. Examples of esterification or transesterification catalysts are acidic catalysts or mixtures thereof. These may be inorganic, organometallic and/or organic acidic compounds. As acidic inorganic catalysts within the meaning of the present invention, use may be made of inorganic acids, such as hydrochloric acid, boric acid, nitric acid, sulfuric acid, phosphoric acid, phosphonic acid or hypophosphorous acid; in addition, acid salts such as aluminum sulfate hydrate, alum, acidic silica gel or acidic aluminum hydroxide may be used. Other acidic inorganic catalysts are, for example, of the formula AI (OR)3And an aluminum compound of the formula Ti (OR)4Wherein the residues R, which may be the same or different, are independently selected from C1-C10Alkyl residues, for example methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, neopentyl, 1, 2-dimethylpropyl, isopentyl, n-hexyl, sec-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl or n-decyl, C3-C12Cycloalkyl residues such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, cycloundecyl and cyclododecyl; preference is given to cyclopentyl, cyclohexyl and cycloheptyl. Preferably, in AI (OR)3And Ti (OR)4The radicals R in (A) are each identical and are selected from the group consisting of isopropyl, butyl and 2-ethylhexyl radicals.
Preferred acidic organometallic catalysts are selected from dialkyltin oxides (R)3)2SnO, wherein R3As defined above. A particularly preferred representative acidic organometallic catalyst is di-n-butyltin oxide, which is known as tin-oxide(oxo-tin) or Fascat<(R)>The forms are commercially available.
Preferred acidic catalysts are organic compounds containing acidic groups, such as phosphate groups, phosphonate groups, sulfonic acid groups, sulfuric acid groups or carboxylic acid groups. Particularly preferred sulfonic acids contain at least one sulfonic acid group and at least one saturated or unsaturated, linear, branched and/or cyclic hydrocarbon residue having from 1 to 40 carbon atoms and preferably from 1 to 24 carbon atoms. In particular, aromatic sulfonic acids are preferred and in particular having one or more C1-C28Alkylaromatic monosulfonic acids of alkyl residues, and especially having C1-C22-those of alkyl residues.
Preferred examples are methanesulfonic acid, butanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, xylenesulfonic acid, 2-amidino-sulfonic acid, 4-ethylbenzene-sulfonic acid, cumene-sulfonic acid, 4-butylbenzenesulfonic acid, 4-octylbenzenesulfonic acid, dodecylbenzenesulfonic acid, didodecylbenzenesulfonic acid, naphthalenesulfonic acid.
Particularly preferred for carrying out the process according to the invention are boric acid, phosphoric acid, polyphosphoric acid and polystyrenesulphonic acids.
In particular, preferred are those of the formula Ti (OR)4And in particular titanium tetrabutylate and titanium tetraisopropylate.
In a further embodiment, acidic and solid catalysts are used in the process of the invention. Examples include zeolites, silica gels, acidic layered silicates, such as montmorillonite, and organic ion exchangers.
Preferably, the process of the present invention is carried out without the use of an esterification or transesterification catalyst.
The amount of catalyst used is typically up to 10% by weight, based on the total mass of the reaction mixture, preferably from 0.01 to 10% by weight, and particularly preferably from 0.02 to 2% by weight.
The reaction mixture is conducted through the reactor. The reaction mixture in the heating zone undergoes intense heating by the supply of thermal energy. This can be done by heat transfer, physical contact with a relatively hot wall, or by interaction of polar or ionic molecules with an electromagnetic field, for example with an electromagnetic field having a wavelength in the centimeter range (microwaves).
According to the present invention, the reaction mixture is fed in the heating zone with sufficiently high thermal energy over a period of up to 60 minutes, typically from 0.1ms to 60 minutes, preferably from 1 second to 10 minutes, and most preferably from 1 second to 2 minutes. The reaction mixture is subjected to an intensive temperature increase and the temperature is from 90 ℃ to 190 ℃, preferably from 120 ℃ to 180 ℃ and particularly preferably from 140 ℃ to 160 ℃ when leaving the heating zone, as measured immediately after leaving the heating zone by means of the temperature sensor PT 100.
The reaction mixture may be present in the reactor under vacuum, atmospheric pressure or in particular under overpressure. Preferably, the pressure in the reactor is from 0 to 1000bar absolute, more preferably from 1mbar to 200bar absolute, especially preferably from 50mbar to 20bar absolute, and most preferably from 1 to 20bar absolute. The pressure in the reactor should be chosen in such a way that, in particular, the reaction mixture and the condensate in the reactor are present in the liquid state during the reaction. In this variant, the reaction mixture is heated efficiently in the reaction zone, in particular in the case of electromagnetic radiation, for example microwave radiation, being used for this purpose.
The residence time in the heating zone is adjusted by selecting a suitable flow rate of the reaction mixture through the heating zone. Another preferred option for adjusting the residence time according to the invention is to suitably select the device dimensions.
In one embodiment of the process according to the invention, the heating zone of the reactor is attached to a residence line (dwell line). The product mixture obtained from the reaction mixture can be retained in this residence line after the heating zone for residence times of up to 60 minutes, preferably from 1 to 600 seconds, particularly preferably from 1 to 120 seconds.
The feeding of the thermal energy required in the heating zone can be performed by any means capable of adding a short period of high thermal energy to the reaction mixture. Examples of suitable devices have been described above.
Due to the short term exposure to high temperatures and pressures on the reaction mixture, the esterification and optionally transesterification reactions take place very rapidly therein. A portion of the alcohol and carboxylic acid present is converted into a carboxylic ester having a relatively low molecular weight and, depending on the starting materials, alcohol and/or reaction water is liberated.
The cooling of the hot product mixture in step iii) may take place in the residence line and/or in a cooling section downstream of the residence zone or the reaction zone. Preferably, the hot product mixture is cooled rapidly, avoiding further conversion.
The resulting product mixture can be combined with other substances as such without further processing or can be worked up before further processing.
According to step iii) as work-up, it is possible, for example, to dry and/or neutralize the product mixture and/or to separate the solid components.
The product mixture, optionally worked up, can be further processed by applying it to a solid carrier and/or by granulating with other substances.
Experiments have shown that the compounds of the formula (I) according to the invention are suitable as metal cations, in particular alkaline earth metal cations, for example Mg2+And Ca2+Particularly preferred complexing agents of (1).
The invention therefore also relates to the use of the compounds of the formula (I) as complexing agents for metal cations.
The invention also relates to the use of the compounds of the formula (I) as complexing agents in detergents and cleaning agents, in oil extraction or for water softening.
In addition, the invention relates to detergents and cleaning agents containing compounds of the formula (I).
As detergents and cleansers, agents for cleaning dishes in particular are possible, in particular those which are suitable for use in automatic dishwashers.
For use in detergents and cleaners, the compounds of formula (I) are generally used in the form of particles which are combined with the other components of the detergents and cleaners.
If the peroxy compound used as a bleaching agent is contacted with a combination of a bleach catalyst and a bleach activator, the bleaching performance in detergents and cleaners can be increased significantly. Here, the bleaching effect of the catalyst is effectively supported by the peroxycarboxylic acid formed by the activator. At the same time, the peroxycarboxylic acids significantly contribute to the microbicidal effect on the items to be cleaned, improve the odor of the washing liquor and prevent the formation of biofilms in the washing machine or dishwasher. Combinations of bleach catalysts and/or bleach activators are therefore useful for increasing bleaching effectiveness and ensuring hygiene when used bleaching in detergents and cleaners.
Preferred washing and cleaning agents according to the invention, in particular dish-cleaning agents, contain the compounds of the formula (I) according to the invention in an amount of from 0.1 to 10% by weight, preferably in an amount of from 0.2 to 8% by weight, and particularly preferably in an amount of from 0.5 to 6% by weight. Percentages refer to the total weight of the detergent and cleanser.
The washing and cleaning agents according to the invention can be present in the form of granules, powders or tablet solids, but also in the form of liquids or pastes, which can in principle contain all known ingredients used in such agents.
In particular, the washing and cleaning agents according to the invention can contain builder substances, peroxy compounds, enzymes, alkali metal carriers, surfactants, pH regulators, organic solvents and other auxiliaries, such as glass corrosion inhibitors, silver corrosion inhibitors and foam regulators. The granules of the invention are suitable for use in formulations containing phosphate and in particular in formulations without phosphate.
Particularly preferred detergents and cleaning agents, in particular dish-cleaning agents, contain:
(i) from 5 to 65% by weight, preferably from 10 to 60% by weight, of a water-soluble builder component,
(ii)5 to 20 wt.%, preferably 8 to 15 wt.%, of a peroxy compound,
(iii)0.5 to 25% by weight of a compound of the formula (I) according to the invention, and
(iv)0 to 50 wt.% of additional additives, such as enzymes, alkali metal carriers, surfactants, pH regulators, organic solvents or other auxiliaries, such as glass corrosion inhibitors, silver corrosion inhibitors and foam regulators, each based on the total weight of the detergent and cleaning agent.
This reagent has in particular a low alkalinity, i.e. its 1 wt% aqueous solution has a pH in the range of 8 to 11.5, and preferably 8 to 11.
Possible ingredients in detergents and cleaning agents are described fully in the patent literature, for example in WO 2018/210442A 1.
Examples of preferred water-soluble builder components in the washing and cleaning agents of the invention are organic polymers of natural or synthetic origin of the polycarboxylate type, which act as co-builders, in particular in hard water areas. For example, polyacrylic acid and copolymers of maleic anhydride and acrylic acid, and the sodium salts of these polymers are contemplated. Commercially available products include those available from BASFCP 5, CP 10 and PA 30. Naturally derived polymers useful as co-builders include, for example, oxidized starch and polyamino acids, such as polyglutamic acid or polyaspartic acid. Other possible water-soluble builder components are naturally occurring hydroxycarboxylic acids, such as mono-, dihydroxysuccinic acid, alpha-hydroxypropionic acid and gluconic acid. Preferred organic water-soluble builder components include salts of citric acid, especially sodium citrate. Depending on the pH finally set in the washing and cleaning agents according to the invention, acids corresponding to the co-builder salts mentioned may also be present. A particularly preferred builder component in formulations without phosphate is methylglycine diacetate (MDGA, e.g. methyl glycine diacetateM, BASF), L-glutamic acid, N, (biscarboxymethyl) -tetrasodium salt (GLDA,DL, Akzo Nobel), sodium polyaspartate: (Lanxess) or salts of iminodisuccinic acid(s) ((II)Lanxess)。
Examples of preferred peroxy components in the washing and cleaning agents of the present invention are perborates and percarbonates, especially the corresponding sodium salts of these compounds.
Enzymes optionally comprised in the washing and cleaning agents of the present invention include proteases, amylases, pullulanases, cutinases and/or lipases. The enzymes used may be adsorbed on a carrier and/or embedded within an encapsulating substance to protect them from premature deactivation. They are typically present in the washing and cleaning agents according to the invention in amounts of up to 10% by weight, and preferably in amounts of from 0.05 to 5% by weight, with particular preference being given to using enzymes which are stable to oxidative degradation.
Preferably, the washing and cleaning agents according to the invention, in particular the agents for cleaning dishes, contain the customary alkali metal carriers, for example alkali metal silicates, alkali metal carbonates and/or alkali metal hydrogencarbonates. Examples of these are given in WO 2018/210442 a 1. The alkali metal carrier may be present in the washing and cleaning agent in an amount of up to 50 wt%, and preferably from 5 to 40 wt%.
Examples of preferred surfactants to be included in the washing and cleaning agents of the invention are anionic surfactants, zwitterionic surfactants and preferably weakly foaming nonionic surfactants. They can be used in amounts of up to 20% by weight, preferably up to 10% by weight, and particularly preferably in the range from 0.5 to 5% by weight, based on the total weight of the washing and cleaning agent. Examples of surfactants are mentioned in WO 2018/210442 a 1.
In order to set the desired pH value (which is not itself derived from a mixture of other components), the washing and cleaning agents according to the invention can contain acids which are compatible with the environment, in particular citric acid, acetic acid, tartaric acid, malic acid, lactic acid, glycolic acid, succinic acid, tryptophan and/or adipic acid, but also inorganic acids, in particular sulfuric acid or alkali metal hydrogen sulfates, or bases, preferably ammonium hydroxide or alkali metal hydroxides. These pH-adjusting agents can be contained in the washing and cleaning agents according to the invention, in particular in the agents for washing dishes, preferably not more than 10% by weight, and particularly preferably from 0.5 to 6% by weight, based in each case on the total weight of the agent.
Examples of preferred organic solvents which are contained in the detergents and cleaners according to the invention are alcohols having 1 to 4 carbon atoms, in particular methanol, ethanol, isopropanol and tert-butanol, glycols having 2 to 4 carbon atoms, in particular ethylene glycol and propylene glycol, and also mixtures thereof and ethers which can be derived from the mentioned groups of compounds. Such water-miscible solvents are typically present in the washing and cleaning agents according to the invention in amounts of not more than 20% by weight, and particularly preferably from 1 to 15% by weight.
In order to inhibit glass corrosion during the rinsing process, suitable inhibitors can be used in the washing and cleaning agents according to the invention, in particular in the agents for cleaning dishes. Particularly advantageous here are crystalline layered silicates and/or zinc salts. Examples of glass corrosion inhibitors are mentioned in WO 2018/210442 a 1.
In a further preferred embodiment, the washing and cleaning agents according to the invention, in particular the agents for cleaning dishes, contain the crystalline layered silicate in an amount of from 0.1 to 20% by weight, more preferably from 0.2 to 15% by weight, and particularly preferably from 0.4 to 10% by weight, based in each case on the total weight of the agent.
For protection against silver corrosion, silver corrosion inhibitors can be used in the washing and cleaning agents according to the invention, in particular in the agents for cleaning dishes. Examples of silver corrosion inhibitors are mentioned in WO 2018/210442 a 1.
The washing and cleaning agents according to the invention, in particular the agents for cleaning dishes, may contain further ingredients known from the prior art for such agents, such as sequestering agents, electrolytes, additional peroxygen activators, dyes or fragrances, such as aromatic oils.
The preparation of the solid detergents and cleaners according to the invention, in particular of agents for cleaning dishes, is not difficult and can in principle be carried out in a manner known per se, for example by spray drying or granulation, wherein the peroxy compound according to the invention and the granules can then be added separately.
The washing and cleaning agents according to the invention, in particular the corresponding agents for cleaning dishes, can be added to the automatic mixer substantially or in solution form by simply mixing the components, particularly advantageously preparing an aqueous solution or a solution containing other customary solvents.
The washing and cleaning agents according to the invention, in particular the agents for cleaning dishes, are preferably obtained in the form of a powderized, granulated or tabletted preparation, which is prepared in a known manner, for example by mixing, granulating, roller compacting and/or by spray drying of the thermally reconstituted components and by adding more sensitive components, in particular enzymes, bleaches and bleach catalysts.
The dish-cleaning machine agent according to the invention can be used in domestic dishwashers as well as in commercial dishwashers. Can be added by hand or by means of a suitable metering device. The application concentration in the cleaning liquid is generally about 1 to 8g/l, preferably 2 to 5 g/l.
The machine rinse program is conveniently supplemented and terminated by some intermediate rinse softening swelling followed by rinsing the dust with clean water cleaning process and with a common rinse detergent. After drying, one will get completely clean and hygienic, flawless dishes when using the dishwashing detergent of the invention.
Examples
In the following examples,% -reference shall mean% by weight, unless explicitly stated otherwise.
Preparation example
Example 1: preparation of oligo citric acid monoethylene glycol ester
2.5kg of citric acid (as monohydrate) are provided in a 5l Buchi autoclave with stirrer having stirrer, internal thermometer and pressure equalizer and mixed with 6.5kg of monoethylene glycol and 0.05kg of sulfuric acid.
The resulting mixture was heated to 80 ℃ and all reactants were completely in solution. The reaction solution was pumped continuously through the reaction tube at an operating pressure of 15bar at 5l/h and exposed to a microwave power output of 1.5kW, 91% of which was absorbed by the reaction material. The residence time of the reaction mixture in the irradiation zone was about 25 seconds. At the end of the reaction tube, the temperature of the reaction mixture was 155 ℃. Immediately after leaving the reactor, the reaction mixture was cooled to room temperature with an intensive heat exchanger.
Example 2 (comparative): production of oligo-citric acid-glyceride
2.5kg of citric acid (monohydrate form) are provided in a 5l Buchi autoclave with stirrer having stirrer, internal thermometer and pressure equalizer and mixed with 4.8kg of glycerol and 0.05kg of methanesulfonic acid.
The resulting mixture was heated to 75 ℃ and all reactants were completely in solution. The reaction solution was pumped continuously through the reaction tube at an operating pressure of 15bar at 5l/h and exposed to a microwave power output of 1.3kW, 94% of which was absorbed by the reaction material. The residence time of the reaction mixture in the irradiation zone was about 25 seconds. At the end of the reaction tube, the temperature of the reaction mixture was 160 ℃. Immediately after leaving the reactor, the reaction mixture was cooled to room temperature with an intensive heat exchanger.
Example 3: production of oligocitric acid monoethylene glycol ester without use of a reaction-promoting catalyst
2.5kg of citric acid (as monohydrate) are provided in a 5l Buchi autoclave with stirrer having stirrer, internal thermometer and pressure equalizer and mixed with 6.5kg of monoethylene glycol. No catalyst was added at this point.
The resulting mixture was heated to 80 ℃ and all reactants were completely in solution. The reaction solution was pumped continuously through the reaction tube at an operating pressure of 15bar at 5l/h and exposed to a microwave power output of 1.5kW, 90% of which was absorbed by the reaction material. The residence time of the reaction mixture in the irradiation zone was about 25 seconds. At the end of the reaction tube, the temperature of the reaction mixture was 155 ℃. Immediately after leaving the reactor, the reaction mixture was cooled to room temperature with an intensive heat exchanger.
Application example
The clear solutions produced according to preparation examples 1,2 and 3 were tested in a citrate-based detergent formulation for dishwashing. It was investigated whether the use of these solutions could prevent the deposition of calcium carbonate on glass and other plates.
The following table describes the compositions of the dishwashing detergents used in the tests.
Watch (A)
Composition (I)
1
2
3
4
Trisodium citrate
36％
35％
35％
35％
Sodium carbonate
30％
30％
30％
30％
Percarbonate salts
15％
15％
15％
15％
TAED
5％
5％
5 5
5％
PEG1500
3％
3％
3％
3％
PEG6000
2％
2％
2％
2％
Sokalan PA25
5％
5％
5％
5％
Lutensol TO 7
1％
1％
1％
1％
Protease Blaze 100T
2％
2％
2％
2％
Amylase Stainzyme event 121
1％
1％
1％
1％
The amount of the fragrance, the dye,etc. of
0％
0％
0％
0％
Mixture according to preparation example 1
0％
1％
0％
0％
Mixture according to preparation example 2
0％
0％
1％
0％
Mixture according to preparation 3
0％
0％
0％
1％
Total up to
100％
100％
100％
100％
The powder formulation was mixed and metered from the metering chamber in 20g portions. The liquid mixture from preparation example 1 or 2 or 3 was metered onto the powder by means of a pipette. The pH value, measured as a 1% by weight solution in water, was 10.2.
The rinse performance was measured in Miele GSL 2 at 55 ℃ using water with a hardness of 21 degrees. Three washing procedures were run through each experiment. Large glass drinking cups made by Schott Zwiesel were visually evaluated for film and stain formation in a black box. Grades 1 to 10 are assigned (1 being the worst value and 10 being the best value). The average of all levels is calculated. The results are listed in the following table.
Watch (A)
Formulation of
1
2
3
4
Film and stain formation
5.9
6.9
5.1
7.6
When mixtures containing monoethylene glycol-dicitrate produced according to preparation examples 1 and 3 were used in the dishwashing detergent formulation, the gloss on glass was significantly improved.
When the mixture containing the monoglycerol-dicitrate produced according to preparation example 2 was used in a dishwashing detergent formulation, there was no improvement in gloss on glass.