WO2022148673A1

WO2022148673A1 - Hydrogenated esterquats from rice bran fatty acids and their preparation

Info

Publication number: WO2022148673A1
Application number: PCT/EP2021/087536
Authority: WO
Inventors: Carsten Cohrs; Kevin James MUTCH
Original assignee: Clariant International Ltd
Priority date: 2021-01-11
Filing date: 2021-12-23
Publication date: 2022-07-14
Also published as: EP4274881A1; CN116783274A

Abstract

Esterquats find major applications as fabric softeners. After Tallow fatty acids and Palm oil fatty acids, fatty acids from sustainable sources like Rice bran fatty acids (RBFA) are desired. RBFA is formed as a by-product during refining of Rice bran oil and hence it is contained in the non edible portion of the oil. However, esterquats from RBFA are often prone to oxidation, which leads to undesired properties in the final products. The present invention relates to esterquats from rice bran fatty acids, wherein the rice bran fatty acids are at least partially hydrogenated rice bran fatty acids (HRBFA). This leads to higher oxidation stability of the esterquats and thus to an overall higher acceptance of the final products.

Description

Hydrogenated esterquats from rice bran fatty acids and their preparation

The invention relates to ester-linked quaternary ammonium compounds, also known as ’’esterquats”, obtained from at least partially hydrogenated rice bran fatty acids (HRBFA), and the preparation of these products. Esterquats are a class of cationic surfactants mainly used in laundry applications such as fabric softeners. Esterquats generally contain a long chain fatty acid group linked to a quaternary ammonium group via an ester linkage.

The structure and composition of esterquats are described e.g. in EP-A 1806392. Esterquats are generally prepared by using triethanolamine esterified with long chain fatty acids (e.g. C16-C18), followed by quaternisation with a suitable quaternising agent, such as dimethyl sulfate. Other types of esterquat structures, such as those mentioned in US 6,072,063 and US 5,811 ,385 are also known. In general, esterquats can be prepared directly from triglyceride oils via a trans esterification step followed by a quaternisation step as described e.g. in WO 2014/069833.

The quality of esterquat products is in particular defined by their activity, acid value, odour and colour, which are parameters affecting both product performance and customer acceptance. So called high quality esterquat products can be obtained by selecting proper parameters during the manufacturing process of the esterquats. For example, it was found that having a low acid value esterquat results in an esterquat composition having higher viscosity as compared to an esterquat having a high acid value. From a product performance perspective, a higher viscosity formulation is perceived as being more stable and often aesthetically more appealing to customers.

EP-A 0981512 describes the use of a typical process to achieve acid values < 6.5 mg KOH/g. US 2009/286712 describes esterquats with low acid values (< 6.7 mg KOH/g) for esterquats synthesised using methyl-diethanolamine. The applications JP 2003277334 A and JP 2003252838 A describe a process wherein no solvent is used during the quaternisation step, which leads to a better quality of the product. US 2017/275560 describes the use of an oxidising agent to achieve a light coloured esterquat product.

Cold processability of esterquats and/or dispersibility of esterquats at low temperatures are further desired properties of the high quality products due to better energy economy and production convenience.

US 2013/196894 describes esterquat composition products synthesised using fatty acids, e.g. from tallow, canola, soybean or palm oil, having an iodine value between 65-85 and a good ester distribution for promoting dispersibility at low temperatures.

Esterquats are generally prepared by using fatty acids based on tallow or vegetable oils such as palm oil. However, there are also other types of vegetable oils that have been reported, including sunflower, soybean and rice bran oil. However a renewable, non-edible (in particular for humans) and sustainable source for esterquats is highly desirable.

Fatty acid esterquats, for example based on palm oil fatty acids, and the use thereof in compositions for various uses, in particular as cationic surfactant in laundry products, have been known for more than 20 years (e.g. US 5,830,845). The use of rice bran fatty acid esterquats as cationic surfactants in fabric softeners has been reported in the publication Gunjan and Vinod K. Tyagi (2014) (“Synthesis of Rice Bran Fatty Acids (RBFAs) Based Cationic Surfactants and Evaluation of Their Performance Properties in Combination with Nonionic Surfactant”, Tenside Surfactants Detergents: Vol. 51, No. 6, pp. 497-505). It is described that rice bran fatty acid esterquats can be prepared by esterification of rice bran fatty acids with hydroxyl-alkylamines, such as diethanolamine (DEA) or triethanolamine (TEA) at 140°C for 3 to 4 hours, and following “quaternisation” of the obtained di-ester using dimethyl sulfate (DMS). The publication also describes dilute esterquat products prepared using hydrolysed fatty acids from rice bran oil. Rice bran fatty acids in general are considered a sustainable resource produced in rice bran processing. Typically, rice bran fatty acids are prepared by hydrolysis of rice bran oil. Even though rice bran oil as such is a by-product of rice bran processing and is considered sustainable, the cost of rice bran oil is high and the oil is categorized as an edible product. Thus, food-grade oil is often wasted for non-food purposes, when it is hydrolysed and used for the synthesis of esterquats. However, during extraction of rice bran oil, a substantial amount of oil undergoes degradation due to enzymatic activity, forming fatty acids in the non-edible crude rice bran oil. To make this oil edible, this oil is refined by separating the fatty acids by alkali refining or steam distillation. The resultant rice bran fatty acids generated as the by-product of rice bran oil are components of a non-edible portion of the oil and hence are more favourable for the production of products unrelated to food. The rice bran fatty acids used in the synthesis of the esterquats of the present invention are those separated from the edible oil in the non-edible portion of rice bran oil.

It has now been found that esterquats prepared from rice bran fatty acids are often prone to oxidation and therefore can be unstable during further processing or in the final products to which they are added. An objective of the present invention is therefore to provide an esterquat based on rice bran fatty acids, which has an acceptable stability towards oxidation. This objective is reached by the ester-linked quaternary ammonium compound of the present invention.

An aspect of the present invention is therefore an ester-linked quaternary ammonium compound comprising at least one hydrocarbon chain derived from at least one rice bran fatty acid from a non-edible source (RBFA), wherein the RBFA is an at least partially hydrogenated rice bran fatty acid (HRBFA) and has an iodine value from 0 to 75, in particular an iodine value from 1 to 70.

Preferably, the RBFA is obtained from a non-edible source that is generated as a by-product during refinement of rice bran oil. The iodine value is determined according to American Oil Chemists’ Society (AOCS) Tg 1a-64 and is used to measure the degree of unsaturation of the fatty acids. At an iodine value of 96 or greater, a large fraction (typically about 25 to 35 wt.-% of the total weight of RBFA) of an RBFA has two or more unsaturated bonds in the hydrocarbon chain. Esterquats comprising hydrocarbon chains derived from such an RBFA are particularly prone to oxidation. Flydrogenation of the RBFA leads to saturation of unsaturated bonds in the hydrocarbon chain, thus reducing the iodine value. At an iodine value of 75 or less, the at least partially hydrogenated RBFA (=HRBFA) contains a small fraction (typically less than 6 wt.-%, preferably less than 3 wt.-%, more preferably less than 2 wt.-% of the total weight of HRBFA) of fatty acids with two or more unsaturated bonds in the hydrocarbon chain. The esterquats comprising hydrocarbon chains derived from such an HRBFA have been found to be significantly more stable towards oxidation. However, it has also been found that with increasing saturation of HRBFA, the viscosity of the esterquats comprising hydrocarbon chains derived therefrom increases, thus that they may become less suited for their specific surfactant applications.

Therefore, the HRBFA is preferably only partially hydrogenated. Accordingly, the iodine value of the HRBFA is preferably 75 or less but greater than 0, more preferably 1 to 70, more preferably 10 to 65, more preferably 15 to 60, more preferably 20 to 55, more preferably 25 to 50.

In one embodiment, the ester-linked quaternary ammonium compound of the invention has a structure of formula (I)

wherein

R¹ represents -(C_nH2n)R⁵ or -(C_nH2n-i)R⁵2;

R² represents C₁-C₄ alkyl, C₂-C₄ alkenyl or C₂-C₄ alkynyl; R³ and R⁴ each independently represent -(C_nH2n)R⁶, -(CnH2n-i)R⁶2, C1-C4 alkyl, C2-C4 alkenyl or C2-C4 alkynyl;

R⁵ represents an acyloxy group having a hydrocarbon chain derived from an HRBFA or an alkoxycarbonyl group having a hydrocarbon chain derived from an HRBFA; each R⁶ independently represents OH, OR², a C₁₂-C₂₅ acyloxy group or a C₁₂-C₂₅ alkoxycarbonyl group;

X- represents an anionic counter-ion; each n independently represents a number from 1 to 4.

In the context of the present invention, the (C_nH2n) moiety in -(C_nH2n)R⁵ and -(C_nH2n)R⁶ is to be understood as a hydrocarbon group with two attachment points, which is not limited to hydrocarbon groups having primary attachment points, such as 1,2-ethylene, 1,3-propylene and 1,4-butylene, but also includes alkylene groups having secondary and tertiary attachment points, such as 1 ,1 -ethylene,

1.1 -propylene, 1 ,1 -butylene, 1,2-propylene, 1,2-butylene, 1,3-butylene,

2.2-propylene, 2,2-butylene, 2,3-butylene and 1,2-isobutylene.

Preferably, the (C_nH2_n) moiety is an alkylene group having a 1 ,2-attachment pattern, such as 1 ,2-ethylene, 1 ,2-propylene, 1 ,2-butylene or 1 ,2-isobutylene, more preferably, 1 ,2-ethylene or 1 ,2-propylene, more preferably 1 ,2-ethylene. Accordingly, the (C_nH2n-i) moiety in -(C_nH2n-i)R⁵2 and -(C_nH2n-i)R⁶2 is to be understood as a hydrocarbon group with three attachment points. Preferably, the (C_nH2_n-i) moiety has a 1,2,3-attachment pattern, as found, e.g. in glycerol and derivatives thereof.

Furthermore, C1-C4 alkyl, C2-C4 alkenyl and C2-C4 alkynyl include both linear, branched and cyclic groups, but are preferably linear or branched groups, more preferably linear groups.

In formula (I), R¹ represents -(C_nH2n)R⁵ or -(C_nH2n-i)R⁵2, preferably -(C_nH2n)R⁵ which comprises at least one of the ester linkages of the ester-linked quaternary ammonium compound of the invention. R¹ is typically introduced into the ester- linked quaternary ammonium compound of the invention prior to quaternisation by, e.g. esterification of an alcohol derived from an HRBFA with an amino carboxylic acid. In this case, R⁵ represents an alkoxycarbonyl group having a hydrocarbon chain derived from an HRBFA. Said alcohol derived from an HRBFA is obtainable e.g. by selective reduction of the carboxylic acid of HRBFA with UAIH₄. Amino carboxylic acids such as glycine, iminodiacetic acid and nitrilotriacetic acid and their derivatives are commercially available. Alternatively, R¹ can be obtained by, e.g. esterification of an HRBFA with an alkanolamine (= amino alcohol), such as ethanolamine, diethanolamine, triethanolamine and their derivatives. In this case, R⁵ represents an acyloxy group having a hydrocarbon chain derived from an HRBFA. Due to easier accessibility, R¹ is preferably obtained by esterification of an HRBFA with an amino alcohol, thus that R⁵ preferably represents an acyloxy group having a hydrocarbon chain derived from an HRBFA.

In formula (I), R² represents C₁-C₄ alkyl, C₂-C₄ alkenyl or C₂-C₄ alkynyl, preferably C₁-C₄ alkyl, more preferably methyl. R² is typically introduced into the ester-linked quaternary ammonium compound of the invention by quaternisation of the respective amine by treatment with a quaternising agent that is suitable for transferring a carbenium ion derived from R².

Furthermore in formula (I), R³ and R⁴ each independently represent - (CnH2n)R⁶, -(CnH2n-i)R⁶2, C1-C4 alkyl, C2-C4 alkenyl or C2-C4 alkynyl, preferably C-i- C₄ alkyl or -(C_nH₂n)R⁶, more preferably methyl or -(C_nH₂n)R⁶ R³ and R⁴ often are already present in the amine used for the synthesis of the ester-linked quaternary ammonium compound of the invention prior to the introduction of R¹. For example, if either of R³ and R⁴ is C₁-C₄ alkyl, it may be present in an alkyl-dialkanolamine such as N-methyl diethanolamine or both may be present in a dialkyl-alkanolamine such as N,N-dimethyl ethanolamine. Alternatively, R³ and/or R⁴ may be introduced into the ester-linked quaternary ammonium compound of the invention during quaternisation after the introduction of R¹, if the amine used for the synthesis of the ester-linked quaternary ammonium compound comprises N-H bonds. Alternatively, if either of R³ and R⁴ is -(C_nH2n)R⁶ or -(C_nH2n-i )R⁶2 wherein R⁶ is OH, it may be present as either of the alkanol moieties of an alkanolamine, such as dialkanolamine, trialkanolamine, alkyl-dialkanolamine, e.g. triethanolamine, or derivatives thereof having two hydroxyl groups.

If R⁶ is OR², it is typically obtained from said alkanol moieties during quaternisation of the respective amine by reaction of the respective alkanol moiety with the quaternising agent.

Alternatively, either of R³ and R⁴ can be -(C_nH2n)R⁶ or -(C_nH2n-i )R⁶2, preferably -(C_nH2n)R⁶, wherein R⁶ is a C12-C25 acyloxy group or a C12-C25 alkoxycarbonyl group. In this case, R³ and/or R⁴ is typically introduced into the ester-linked quaternary ammonium compound of the invention in the same way as R¹, however with a C12-C25 carboxylic acid instead of HRBFA, which may be the same as the HRBFA or different. Preferably, the use of the C12-C25 carboxylic acid results in a total iodine value of all fatty acids of from 0 to 75, more preferably 1 to 70 more preferably 10 to 65, more preferably 15 to 60, more preferably 20 to 55, more preferably 25 to 50. For example, the C12-C25 carboxylic acid can be different from the HRBFA. In this case, it is preferably a saturated C12-C25 carboxylic acid, more preferably selected from saturated C14-C20 carboxylic acids, more preferably from saturated C16 and C18 carboxylic acids, more preferably a saturated C16 carboxylic acid, in which case it has an iodine value of 0. If this is the case, the C12-C25 carboxylic acid is typically admixed to said HRBFA before the HRBFA is further processed into the ester-linked quaternary ammonium compound of the invention. Alternatively, the C12-C25 carboxylic acid can be a HRBFA, preferably a HRBFA obtained from a non-edible source. In this case, the C12-C25 carboxylic acid, from which the hydrocarbon chain in R⁶ is derived may be the HRBFA from which the hydrocarbon chain in R⁵ is derived and/or may be obtained in the same process as said HRBFA and therefore itself has an iodine value of from 0 to 75, more preferably 1 to 70, more preferably 10 to 65, more preferably 15 to 60, more preferably 20 to 55, more preferably 25 to 50. In embodiments wherein R¹ represents -(C_nH2n-i)R⁵2, each of R², R³ and R⁴ preferably represents C1-C4 alkyl.

Furthermore in formula (I), X- represents an anionic counter-ion. Typically, this counter-ion is introduced during quaternisation of the respective amine and originates from the quaternising agent used for introducing the R² group. Such quaternising agent may be selected from e.g. oxonium salts, halides, phosphates, carbonates, sulphonates and sulphates of the respective R² group. X- is thus the respective anion obtainable by removing an (R²)⁺ carbenium ion from the quaternising agent. Preferably X- is selected from halide and alkyl sulphate, more preferably chloride or methyl sulphate.

Furthermore in formula (I), each n independently represents a number from 1 to 4, preferably a number from 2 to 3, more preferably 2. Preferably each n is the same and represents 2.

In an embodiment of the present invention, the ester-linked quaternary ammonium compound has a structure of formula (I) as defined above, wherein R² represents C1-C4 alkyl, preferably methyl;

R³ and R⁴ each independently represent C1-C4 alkyl, preferably methyl, or -(CnH_2n)R⁶;

R⁵ represents an acyloxy group having a hydrocarbon chain derived from an HRBFA; each R⁶ independently represents OH, OR² or a C₁₂-C₂₅ acyloxy group;

X- represents halide or alkyl sulphate, preferably chloride or methyl sulphate.

In another embodiment, the ester-linked quaternary ammonium compound has a structure of formula (I) as defined above, wherein each R⁶ independently represents OH, OR² or an acyloxy group having a hydrocarbon chain derived from an RBFA, preferably from an FIRBFA. In another embodiment, the ester-linked quaternary ammonium compound has a structure of formula (I) as defined above, wherein

R³ is C1-C4 alkyl, preferably methyl, or -(C_nH2n)R⁶, with R⁶ being OH or OR², and

R⁴ is -(C_nH2n)R⁶, with R⁶ being an acyloxy group having a hydrocarbon chain derived from an RBFA, preferably from an HRBFA.

In another embodiment, the ester-linked quaternary ammonium compound has a structure of formula (I) as defined above, wherein R³ and R⁴ represent -(C_nH2n)R⁶, wherein each R⁶ independently represents OH or OR².

In another embodiment, the ester-linked quaternary ammonium compound has a structure of formula (I) as defined above, wherein R³ and R⁴ represent -(C_nH2n)R⁶, wherein each R⁶ is an acyloxy group having a hydrocarbon chain derived from an RBFA, preferably from an HRBFA.

In another embodiment, the ester-linked quaternary ammonium compound has a structure of formula (I) as defined above, wherein R³ and R⁴ each independently represents C1-C4 alkyl, preferably methyl.

In one embodiment, the ester-linked quaternary ammonium compound has a structure of one of following formulae (la), (lb), (lc), (Id), (le), (If), (Ig), (Ih), (Ij), (Ik), (Im), (In), (lo), (Ip), (Iq), (Ir), (Is), (It), (lu), (Iv) and (Iw), wherein R⁵ and R⁶ each represent an acyloxy group having a hydrocarbon chain derived from an HRBFA, and X represents halide or alkyl sulphate, preferably chloride or methyl sulphate.

(Iw).

In a preferred embodiment, the ester-linked quaternary ammonium compound has a structure of one of formulae (la), (lc), (le), (Ig), (Ij), (Im), (lo), (Iq), (Is) and (lu). In another preferred embodiment, the ester-linked quaternary ammonium compound has a structure of one of formulae (lb), (Id), (If), (Ih), (Ik), (In), (Ip), (Ir), (It) and (lv). In another preferred embodiment, the ester-linked quaternary ammonium compound has a structure of formula (Iw). In another preferred embodiment, the ester-linked quaternary ammonium compound has a structure of one of formulae (la) and (lb). In another preferred embodiment, the ester-linked quaternary ammonium compound has a structure of one of formulae (lc) and (Id).

In another preferred embodiment, the ester-linked quaternary ammonium compound has a structure of one of formulae (le) and (If). In another preferred embodiment, the ester-linked quaternary ammonium compound has a structure of one of formulae (Ig) and (Ih). In another preferred embodiment, the ester-linked quaternary ammonium compound has a structure of one of formulae (Ij) and (Ik).

In another preferred embodiment, the ester-linked quaternary ammonium compound has a structure of one of formulae (Im) and (In). In another preferred embodiment, the ester-linked quaternary ammonium compound has a structure of one of formulae (lo) and (Ip). In another preferred embodiment, the ester-linked quaternary ammonium compound has a structure of one of formulae (Iq) and (Ir). In another preferred embodiment, the ester-linked quaternary ammonium compound has a structure of one of formulae (Is) and (It). In another preferred embodiment, the ester-linked quaternary ammonium compound has a structure of one of formulae (lu) and (Iv).

Another aspect of the present invention is a mixture of ester-linked quaternary ammonium compounds comprising at least one, preferably at least two ester linked quaternary ammonium compounds of the invention, as described above.

The mixture of the invention can be a mixture of at least one ester-linked quaternary ammonium compound of the invention as described above with any other ester-linked quaternary ammonium compound, e.g. with one or more ester- linked quaternary ammonium compounds of formula (I) as described above, wherein R⁵ and, if applicable, R⁶ represent an acyloxy group or an alkoxycarbonyl group having a hydrocarbon chain derived from a fatty acid that is not an HRBFA. In this case, the hydrocarbon chain is preferably derived from a C12-C25 fatty acid having an iodine value of 0 to 75, more preferably 1 to 70, more preferably 10 to 65, more preferably 15 to 60, more preferably 20 to 55, more preferably 25 to 50. Also preferably, the hydrocarbon chain is derived from a C14-C20, more preferably from a C16 or C18, more preferably from a C16 fatty acid that is not an HRBFA.

Alternatively, the mixture of the invention can be a mixture of at least two ester- linked quaternary ammonium compounds of the invention as described above, without other ester-linked quaternary ammonium compounds.

In one embodiment, the mixture of the invention is a mixture of ester-linked quaternary ammonium compounds having structures of at least two of formulae (la), (lb), (lc), (Id), (le), (If), (Ig), (Ih), (Ij), (Ik), (Im), (In), (lo), (Ip), (Iq), (Ir), (Is), (It), (lu), (Iv) and (Iw), wherein R⁵ and R⁶ each represent an acyloxy group having a hydrocarbon chain derived from an HRBFA, and X- represents halide or alkyl sulphate, preferably chloride or methyl sulphate. In a preferred embodiment, the mixture of the invention is a mixture of ester-linked quaternary ammonium compounds having structures of at least two of formulae (la), (lc), (le), (Ig), (Ij), (Im), (lo), (Iq), (Is) and (lu). In another preferred embodiment, the mixture of the invention is a mixture of ester-linked quaternary ammonium compounds having structures of at least two of formulae (lb), (Id), (If), (Ih), (Ik), (In), (Ip), (Ir), (It) and (Iv).

In another preferred embodiment, the mixture of the invention is a mixture of ester- linked quaternary ammonium compounds having structures of at least two of formulae (la), (Is) and (lu). In another preferred embodiment, the mixture of the invention is a mixture of ester-linked quaternary ammonium compounds having structures of at least two of formulae (lb), (It) and (Iv). In another preferred embodiment, the mixture of the invention is a mixture of ester-linked quaternary ammonium compounds having structures of at least two of formulae (lb), (It) and (Iv). In another preferred embodiment, the mixture of the invention is a mixture of ester-linked quaternary ammonium compounds having structures of at least two of formulae (lc), (Ig), (Ij), (Im), (lo), and (Iq).

In another preferred embodiment, the mixture of the invention is a mixture of ester- linked quaternary ammonium compounds having structures of at least two of formulae (Id), (Ih), (Ik), (Ip) and (Ir).

Another aspect of the present invention is a process for the production of an ester- linked quaternary ammonium compound or of a mixture of ester-linked quaternary ammonium compounds, comprising the steps of:

(i) catalytic hydrogenation of a rice bran fatty acid (RBFA) or a mixture of rice bran fatty acids (RBFAs) from a non-edible source to an iodine value of from 0 to 75, preferably 1 to 70, more preferably 10 to 65, more preferably 15 to 60, more preferably 20 to 55, more preferably 25 to 50, in order to obtain an at least partially hydrogenated rice bran fatty acid (FIRBFA) or a mixture of at least partially hydrogenated rice bran fatty acids (FIRBFAs);

(ii) optionally mixing the FIRBFA or FIRBFAs with one or more C12-C25 fatty acids thus that the overall iodine value of all fatty acids remains within the range of from 0 to 75, preferably 1 to 70, more preferably 10 to 65, more preferably 15 to 60, more preferably 20 to 55, more preferably 25 to 50; (iii) esterification of the HRBFA, HRBFAs or, if applicable, of the mixture obtained in step (ii) with an alkanolamine of formula (II)

wherein

R¹¹ represents -(C_nFl2n)OFI or -(C_nFl2n-i)(OFI)2, preferably -(C_nFl2n)OFI; R³¹ and R⁴¹ each independently represent -(C_nFl2n)OFI, -(C_nFl2n-i)(OFI)2, H, C1-C4 alkyl, C2-C4 alkenyl or C2-C4 alkynyl, preferably -(C_nFl2n)OFI, FI or C1-C4 alkyl; and each n independently represents a number from 1 to 4, to obtain an ester amine (EA) or a mixture of ester amines (EAs)

(iv) quaternising the EA or EAs with a quaternising agent, preferably dimethyl sulphate.

In step (i) of the process of the present invention, a rice bran fatty acid from a non edible source (RBFA), or a mixture of several rice bran fatty acids from a non edible source (RBFAs), are used.

The rice bran oil, from the refinement of which the non-edible source of rice bran fatty acids is generated, is not particularly limited. It is, however, desirable to select rice bran oil that is a side product of rice bran processing. The rice bran itself is also not limited to specific rice bran, but is preferably rice bran that is a by-product of rice processing.

The rice bran fatty acids from non-edible sources are usually obtained as a mixture of several fatty acids and often contain impurities that prevent the formation of high quality esterquats. Therefore the rice bran fatty acids are preferably separated from impurities prior to or after catalytic hydrogenation. It may be beneficial to carry out the separation after catalytic hydrogenation, in order to remove residual metal catalysts and by products generated during catalytic hydrogenation. Separation techniques for rice bran fatty acids may include any known separation techniques that are applicable for the separation of fatty acids from each other and/or from further impurities. These separation techniques include, but are not limited to crystallisation, winterisation, distillation, sublimation, filtration, adsorption on high surface materials such as activated carbon or bleaching earths, chromatography including column, flash, and high performance liquid chromatography, liquid-liquid extraction and solid-liquid-extraction.

Preferable separation techniques are crystallisation, winterisation and/or distillation. If a single rice bran fatty acid from a non-edible source (RBFA) is used, at least one of the above separation techniques has to be applied after impurities have been removed and prior to catalytic hydrogenation, since the non-edible source typically contains a mixture of different rice bran fatty acids. If a mixture of rice bran fatty acids from a non-edible source (RBFAs) is used, the mixture may be used without separation of any individual RBFA, or after removal of certain RBFA.

In step (i) of the process of the invention, the RBFA or RBFAs are subjected to catalytic hydrogenation. This step is typically carried out with hydrogen in the presence of a hydrogenation catalyst. Preferably, the hydrogenation catalyst is a group 8, 9, 10 or 11 transition metal hydrogenation catalyst, e.g. a ruthenium hydrogenation catalyst, a cobalt hydrogenation catalyst, a rhodium hydrogenation catalyst, an iridium hydrogenation catalyst, a nickel hydrogenation catalyst, a palladium hydrogenation catalyst, a platinum hydrogenation catalyst or a copper hydrogenation catalyst. Preferably, the hydrogenation catalyst is a nickel hydrogenation catalyst. The catalytic hydrogenation is typically carried out in the absence of oxygen, which may be obtained by e.g. flushing the reaction vessel with an inert gas such as nitrogen, argon or helium. In this case, the flushing is carried out for at least 20 min, preferably at least 40 min, more preferably at least 60 min. Alternatively, the reaction vessel can be flushed with hydrogen, which is used in the subsequent hydrogenation reaction.

Alternatively, the absence of oxygen can be established by repeatedly applying vacuum to the vessel and flooding the vessel with inert gas or with hydrogen. In this case, the vacuum and flooding is carried out at least twice, preferably at least 3 times, more preferably at least 5 times.

For example, catalytic hydrogenation of step (i) can be carried out at a reaction temperature of from 60 to 300°C, preferably from 100 to 250°C, more preferably from 150 to 200°C, more preferably from 160 to 180°C, more preferably from 170 to 175°C. Furthermore, catalytic hydrogenation of step (i) can be carried out for example at a hydrogen gas pressure of from 3 to 15 kg/cm², preferably from 5 to 12 kg/cm², more preferably from 7 to 10 kg/cm², more preferably from 7.5 to 8 kg/cm². In one embodiment, catalytic hydrogenation is carried out at a reaction temperature of from 100 to 250°C and a hydrogen gas pressure of from 3 to 15 kg/cm². In another embodiment, it is carried out at a reaction temperature of from 150 to 200°C and a hydrogen gas pressure of from 5 to 12 kg/cm².

In another embodiment, it is carried out at a reaction temperature of from 160 to 180°C and a hydrogen gas pressure of from 7 to 10 kg/cm². In another embodiment, it is carried out at a reaction temperature of from 170 to 175°C and a hydrogen gas pressure of from 7.5 to 8 kg/cm². The catalyst loading, based on the total weight of RBFAs, can for example be from 0.01 to 2 wt.-%, preferably from 0.05 to 1 wt.-%, more preferably from 0.1 to 0.8 wt.-%, more preferably from 0.3 to 0.5 wt.-%.

The catalytic hydrogenation of step (i) is carried out until the RBFA or RBFAs are at least partially hydrogenated to an iodine value of from 0 to 75, preferably 1 to 70, more preferably 10 to 65, more preferably 15 to 60, more preferably 20 to 55, more preferably 25 to 50, in order to obtain an at least partially hydrogenated rice bran fatty acid (FIRBFA) or a mixture of at least partially hydrogenated rice bran fatty acids (FIRBFAs). RBFAs contain mono and polyunsaturated fatty acids. Therefore, the catalytic hydrogenation of RBFAs typically results in mixtures of cis and trans fatty acids. Although all FIRBFAs, independent of their cis and trans content, can be used for the preparation of ester-linked quaternary ammonium compounds, it is preferred to use FIRBFAs with a trans-content of less than 20 wt.-%, more preferred less than 15 wt.-%, more preferred less than 10 wt.-% and even more preferred less than 5 wt.-%, based on the total weight of FIRBFAs.

In optional step (ii), the FIRBFA or FIRBFAs can be mixed with one or more C12-C25 fatty acids thus that the overall iodine value of all fatty acids remains within the range of from 0 to 75, preferably 1 to 70, more preferably 10 to 65, more preferably 15 to 60, more preferably 20 to 55, more preferably 25 to 50. This step is typically carried out in order to adjust the distribution of hydrocarbon chains of the final ester-linked quaternary ammonium compound, if a specific distribution, which cannot be obtained by RBFAs from the employed non-edible source, is required for a specific application.

These fatty acids preferably are selected from saturated C14-C20 fatty acids, more preferably from saturated C16 or C18 fatty acids, more preferably are a saturated C16 fatty acid. In one embodiment, step (ii) is carried out. In another embodiment, step (ii) is not carried out. If step (ii) is carried out, the fatty acids are preferably obtained from a non-edible source.

In step (iii), the FIRBFA, FIRBFA or, if step (ii) was carried out, the mixture obtained in step (ii), is subjected to an esterification reaction with an alkanolamine of formula (II)

wherein

R¹¹ represents -(C_nH2n)OH or -(C_nH2n-i)(OH)2, preferably -(C_nH2n)OH; R³¹ and R⁴¹ each independently represent -(C_nH2n)OH, -(C_nH2n-i)(OH)2, H, C1-C4 alkyl, C2-C4 alkenyl or C2-C4 alkynyl, preferably -(C_nH2n)OH, H or C1-C4 alkyl; and each n independently represents a number from 1 to 4, to obtain an ester amine (EA) or a mixture of ester amines (EAs).

The esterification reaction of step (iii) is typically carried out at temperatures between 50 and 250°C, preferably between 100 and 220°C, more preferably between 150 and 200°C. If the temperature is too low, the reaction is significantly slowed down and thus is not applicable on an industrial scale. However, if the temperature is too high, decomposition products occur at a high rate, thus limiting the usefulness of the product mixture. The esterification reaction of step (iii) is preferably carried out under atmospheric pressure.

Preferably, the esterification step (i) is carried out under conditions in which generated water is continuously removed from the reaction vessel. For example, water removal may be accomplished by adding molecular sieves to the reaction mixture, by attaching a Dean-Stark-apparatus or distillation apparatus to the reaction vessel, or by applying vacuum to the reaction vessel. More preferably, the reaction is carried out under vacuum and/or with a distillation apparatus attached.

In one embodiment, the alkanolamine of formula (II) is selected from those having structures of any of following formulae (I la), (Mb), (lie), (lid), (Me), (Ilf), (Mg), (llh), (Mj), (Ilk), (Mm), (Mn), (Mo), (lip) and (Mq).

(llq).

In another embodiment, the alkanolamine is selected from those having structures of any of formulae (I la), (lie), (lie), (llg), (llj) and (llm). In another embodiment, the alkanolamine is selected from those having structures of any of formulae (Mb),

(lid), (Ilf), (llh), (Ilk) and (lln). In another embodiment, the alkanolamine is selected from those having structures of any of formulae (Mo), (lip) and (llq). In another embodiment, the alkanolamine is selected from those having structures of any of formulae (lla), (Me) and (Mm). In another embodiment, the alkanolamine is selected from those having structures of any of formulae (Mb), (lid) and (lln).

The alkanolamine used in the process according to the invention may be any alkanolamine, however tertiary alkanolamines are preferred due to potential side reactions of N-H amines with HRBFAs during the esterification step. Even more preferred are trialkanolamines, especially triethanolamine.

The molar ratio of rice bran fatty acids to alkanolamine in the esterification step (iii) is typically from 1 :2 to 3: 1 , preferably 1 :1 to 3: 1 , more preferably from 1 :1 to 2: 1 . If the ratio is too low, the resultant ester amines are formed in an undesirably low concentration. However, if it is too high, the resultant product exceeds the desired acidity. Accordingly, depending on the ratio and the employed alkanolamine, the resultant ester amine (EA) or mixture of ester amines (EAs) may contain monoesters, diesters, triesters or mixtures thereof. The quaternisation step (iv) is typically carried out at temperatures from 0 to 180°C, preferably from 20 to 120°C, more preferably from 50 to 100°C. If the temperature is too low, the reaction is significantly slowed down and thus is not applicable on an industrial scale.

However, if the temperature is too high, decomposition products occur at a higher rate and undesired methylation of the other functional groups may take place.

The quaternising agent in the quaternization step (iv) is not particularly limited and may be selected, e.g. from trialkyl oxonium salts, alkyl halides, dialkyl phosphates, dialkyl carbonates, alkyl sulphonates and dialkyl sulphates, however dialkyl sulphates and alkyl halides are preferred, especially dimethyl sulphate and methyl chloride, in particular dimethyl sulphate.

In the quaternization step (iv) the molar ratio between the ester amine and the quaternising agent is typically from 2:1 to 1:3, preferably from 1.5:1 to 1:2, most preferably from 1.1:1 to 1 : 1.1. If the ratio is too low, the quaternisation of the ester amine or the mixture of ester amines is not complete after the reaction is finished.

If the ratio is too high, there is a risk that other functional groups of the product are alkylated.

Preferably, at least a part of the quaternisation step (iv), often the full quaternization step (iv) is carried out in the absence of a solvent, because solvents may be alkylated by the quaternizing agent, which may result in increased odour of the final product. However, one or more solvents may be added to the resultant mixture after the quaternization is at least partially completed, or fully completed. The solvent is not particularly limited, and can be selected from, e.g. lower alcohols having from 1 to 6 carbon atoms such as ethyl alcohol, propyl alcohol, isopropyl alcohol, etc; polyols, such as ethylene glycol, diethylene glycol, propylene glycol, polyethylene glycol and glycerin, and they can be used alone or in a combination thereof. Preferably the solvent added after the at least partial completion of the quaternization step is the polyol propylene glycol or an alcohol, more preferably ethanol, isopropanol or propylene glycol. The solvent may comprise further solvent components, such as aromatic hydrocarbons, aliphatic hydrocarbons, ethers, esters, lactones, lactams, amides, amines, furans and others. Preferably the solvent does not contain any of these further solvent components.

The process according to the present invention leads to an ester-linked quaternary ammonium compound or a mixture of ester-linked quaternary ammonium compounds that has high quality. The ester-linked quaternary ammonium compound or mixture of ester-linked quaternary ammonium compounds has a low acid value, a low level of odour and a low level of coloured stain.

The acid value of the ester-linked quaternary ammonium compound or mixture of ester-linked quaternary ammonium compounds prepared by the process according to the invention is typically lower than 7 mg KOH/g of the sample, and usually originates from the content of amine salts and free fatty acids in the product. The acid value may be determined by the recent standard method DIN EN ISO 2114.

The odour of the ester-linked quaternary ammonium compound or mixture of ester-linked quaternary ammonium compounds mostly originates from the solvent employed in or after the quaternisation step (ii), which solvent is often alkylated by the quaternising agent to give compounds with unpleasant odour. The ester-linked quaternary ammonium compound or mixture of ester-linked quaternary ammonium compounds acquired by the process of the invention typically contains alkylated solvents, preferably alkylated alcohols, in particular methyl ethyl ether or methyl isopropyl ether in an amount below 10000 ppm, preferably below 5000 ppm, more preferably below 2000 ppm, as determined by integration of the corresponding resonance signals, preferably of the signals arising from the methyl groups introduced by the quaternising agent, in the ¹H NMR spectrum of a sample of the ester-linked quaternary ammonium compound or mixture of ester-linked quaternary ammonium compounds.

The colour of the ester-linked quaternary ammonium compound or mixture of ester-linked quaternary ammonium compounds acquired by the process according to the invention typically has a value of less than 8, preferably less than 5, more preferably 4 or less on the Gardner colour scale according to the recent standard method ASTM D1544.

The ester-linked quaternary ammonium compound or mixture of ester-linked quaternary ammonium compounds acquired by the process according to the invention preferably has an active esterquat content of above 0.7 meq/g, more preferably of above 0.8 meq/g, most preferably of above 1.0 meq/g, measured by Epton titration according to the recent standard method DIN EN ISO 2871.

Another aspect of the present invention is the use of an at least partially hydrogenated rice bran fatty acid (HRBFA) or a mixture of at least partially hydrogenated rice bran fatty acids (HRBFAs) from a non-edible source for the production of an ester-linked quaternary ammonium compound or a mixture of ester-linked quaternary ammonium compounds, wherein the FIRBFA or FIRBFAs have an iodine value from 0 to 75, preferably 1 to 70, more preferably 10 to 65, more preferably 15 to 60, more preferably 20 to 55, more preferably 25 to 50.

In the following examples and claims, the invention is disclosed in more detail.

EXAMPLES

Examples 1 , 2 and 3 (Hydrogenation of RBFA)

A mixture of rice bran fatty acids (RBFAs) from the non-edible portion obtained during refinement of rice bran oil was subjected to catalytic hydrogenation using a pressure reactor and a Nickel catalyst for hydrogenation of fatty acids (SCAT 2234 obtained from Suhans Chemicals). 7000 kg of pre-melted RBFAs were charged to the pressure reactor and 28 kg of the catalyst was added.

The mixture was purged of oxygen by means of nitrogen gas and heated to 170-175°C. Hydrogen gas was introduced into the reactor and the pressure of hydrogen was maintained at 7.5 - 8 kg/cm². The hydrogenation reaction was monitored by analyzing the iodine value and composition (gas chromatography). Three HRBFA samples of 50 kg each with iodine values of 49.0 (example 1 ),

38.8 (example 2) and 30.4 (example 3) were isolated after 120 min, 180 min and 240 min, respectively, and filtered through a filter press for further use. The parameters of the hydrogenation reaction are listed in Table 1

Table 1

The compositions of fatty acids in the HRBFAs obtained from hydrogenation are listed in Table 2.

Table 2

C-16 and C-18 indicate the C-chain length, 1 ” and “:2” indicate the number of unsaturated bonds.

Examples 4, 5 and 6 (Conversion)

The HRBFA samples from examples 1 , 2 and 3 were further converted into ester- linked ammonium compounds via the following method.

2250 g (8 moles) of FIRBFAs were subjected to a reaction with 787 g triethanolamine (5.28 moles) using 0.2 g of the catalyst hypophosphoric acid (25 ppm) at 180°C for 6 hours under atmospheric pressure while water was continuously removed by distillation. 2900 g of a mixture of ester amines (5.28 moles) were isolated and cooled to room temperature.

2800 g (5.11 moles) of the EAs were heated to 80°C and 628 g (4.9 moles) of dimethyl sulfate (DMS) was added over the period of 105 minutes, and the reaction was continued for an additional 10 minutes to allow DMS to react. The development of a highly viscous mass indicated the reaction with DMS. Thereafter, 380 g of ethanol were added continuously over the period of 80 minutes and the reaction was continued for a further two hours at 80°C. Approximately 3810 g of a light yellow colored mixture of ester-linked ammonium compounds were obtained. The results are listed in Table 3.

Table 3

The ester-linked ammonium compounds of examples 4, 5 and 6 were evaluated by measuring the softness of towels using PhabrOmeter (Nu Cybertek Inc.) according to their standard procedure (AATCC Test method TM202) and compared to a commercially available product made from palm oil fatty acid-based esterquat Praepagen TQOV-IPA.

Washing procedure:

White hand towels (100% cotton, brand: Rhema, Indonesia, 30 cm x 28 cm) were prewashed with a common detergent. 25 g of the ester-linked ammonium compound were dissolved in tap water and stirred for 1 minute. Prewashed towels were soaked in the solution for 30 minutes and spin dried. Dried towels were conditioned in a room with constant humidity and temperature. The softness was evaluated by relative hand value (RHV, AATCC Test method TM202, Nu Cybertek Inc.), with higher values indicating softer fabrics. The results are listed in Table 4.

Table 4

From the results it is evident that the ester-linked quaternary ammonium compounds of the invention can be used to obtain softer fabrics than commercially available palm oil fatty acid-based esterquats, such as Praepagen TQOV-IPA (of Clariant).

Claims

Patent Claims

1. An ester-linked quaternary ammonium compound comprising at least one hydrocarbon chain derived from at least one rice bran fatty acid from a non-edible source (RBFA), wherein the RBFA is an at least partially hydrogenated rice bran fatty acid (HRBFA) and has an iodine value from 0 to 75.

2. The ester-linked quaternary ammonium compound according to claim 1 , wherein the HRBFA is a partially hydrogenated rice bran fatty acid having an iodine value from 1 to 70, in particular from 10 to 65.

3. The ester-linked quaternary ammonium compound according to claim 1 or 2 having a structure of formula (I)

wherein

R¹ represents -(C_nH2n)R⁵ or -(C_nH2n-i)R⁵2, preferably -(C_nH2n)R⁵;

R² represents C₁-C₄ alkyl, C₂-C₄ alkenyl or C₂-C₄ alkynyl;

R³ and R⁴ each independently represent -(C_nH2n)R⁶, -(CnH2n-i)R⁶2, C1-C4 alkyl, C2- C4 alkenyl or C2-C4 alkynyl; each R⁵ independently represents an acyloxy group having a hydrocarbon chain derived from an HRBFA or an alkoxycarbonyl group having a hydrocarbon chain derived from an HRBFA; each R⁶ independently represents OH, OR², a C12-C25 acyloxy group or a C12-C25 alkoxycarbonyl group;

4. The ester-linked quaternary ammonium compound according to claim 3, wherein

R² represents C₁-C₄ alkyl, preferably methyl;

X- represents halide or alkyl sulphate, preferably chloride or methyl sulphate.

5. The ester-linked quaternary ammonium compound according to claim 3 or 4, wherein each n is 2.

6. The ester-linked quaternary ammonium compound according to any one of claims 3 to 5, wherein each R⁶ independently represents OH, OR² or an acyloxy group having a hydrocarbon chain derived from an RBFA, preferably from an HRBFA.

7. The ester-linked quaternary ammonium compound according to any one of claims 3 to 6, wherein

8. The ester-linked quaternary ammonium compound according to any one of claims 3 to 6, wherein R³ and R⁴ represent -(C_nH2n)R⁶, wherein each R⁶ independently represents OH or OR².

9. A mixture of ester-linked quaternary ammonium compounds comprising at least one, preferably at least two ester-linked quaternary ammonium compounds according to any one of claims 1 to 8.

10. A process for the production of an ester-linked quaternary ammonium compound or of a mixture of ester-linked quaternary ammonium compounds, comprising the steps of:

(i) catalytic hydrogenation of a rice bran fatty acid (RBFA) or a mixture of rice bran fatty acids (RBFAs) from a non-edible source to an iodine value of from 0 to 75, in order to obtain an at least partially hydrogenated rice bran fatty acid (FIRBFA) or a mixture of at least partially hydrogenated rice bran fatty acids (FI RBFAs);

(ii) optionally mixing the FIRBFA or FIRBFAs with one or more C12-C25 fatty acids thus that the overall iodine value of all fatty acids remains within the range of from 0 to 75;

(iii) esterification of the FIRBFA, FIRBFAs or, if applicable, of the mixture obtained in step (ii) with an alkanolamine of formula (II)

wherein

R¹¹ represents -(C_nFl2n)OFI or -(C_nFl2n-i)(OFI)2, preferably -(C_nFl2n)OFI; R³¹ and R⁴¹ each independently represent -(C_nFl2n)OFI, -(C_nFl2n-i)(OFI)2, FI, C1-C4 alkyl, C2-C4 alkenyl or C2-C4 alkynyl, preferably -(C_nFl2n)OFI, FI or C1-C4 alkyl; and each n independently represents a number from 1 to 4, to obtain an ester amine (EA) or a mixture of ester amines (EAs)

(iv) quaternizing the EA or EAs with a quaternizing agent, preferably dimethyl sulphate.

11. The process according to claim 10, wherein the alkanolamine in the esterification step (iii) is a trialkanolamine, dialkanolamine or alkyl-dialkanolamine, preferably triethanolamine.

12. The process according to claim 10 or 11 , wherein at least a part of the quaternization step (iv), preferably the full quaternization step (iv) is carried out without a solvent, and a solvent is optionally added only after the at least partial completion, preferably full completion, of the quaternization step (iv).

13. The process according to any one of claims 10 to 12, wherein a solvent is added after the quaternization step (iv) and the solvent is propylene glycol or an alcohol, preferably ethanol, isopropanol or propylene glycol.

14. The process according to any one of claims 10 to 13, wherein the catalytic hydrogenation in step (i) is performed with hydrogen in the presence of a group 8, 9, 10 or 11 transition metal hydrogenation catalyst, preferably a nickel catalyst.

15. Use of an at least partially hydrogenated rice bran fatty acid (HRBFA) or a mixture of at least partially hydrogenated rice bran fatty acids (HRBFAs) from a non-edible source for the production of an ester-linked quaternary ammonium compound or a mixture of ester-linked quaternary ammonium compounds, wherein the FIRBFA or FIRBFAs have an iodine value from 0 to 75.