WO2010121591A1 - Method for the production of hydrocarbons from fatty alcohols, and use of hydrocarbons thus produced - Google Patents

Abstract

The invention relates to a method for producing paraffins or paraffin mixtures from fatty alcohols or fatty alcohol mixtures and the use thereof in cosmetic compositions, as leather and textile auxiliaries, in dyes and lacquers, and in lubricants.

Description

 Process for the preparation of hydrocarbons from fatty alcohols and use of such produced hydrocarbons

The present invention relates to a process for the preparation of hydrocarbons from fatty alcohols or fatty alcohol oligomers and their use in cosmetic compositions, as leather and textile auxiliaries, in paints and varnishes and in lubricants.

The oligomerization of alpha olefins to mixtures of olefin dimers, trimers and oligomers is known. Depending on the catalyst and the reaction conditions used, the product distribution can be shifted to dimers, trimers or longer-chain oligomers.

Branched hydrocarbons in the form of the oligomers of long chain alpha-olefins, such as their hydrogenated products, are known per se, e.g. as dimers of 1-decene or 1-dodecene. Such products are e.g. has been proposed as an ingredient of cosmetic compositions (see WO 2004/082641).

It has also been proposed (WO 2007/068371) to make paraffins accessible by dehydroxymethylation from fatty alcohols. However, these have a chain shorter by one C atom and are therefore not atom-economical, even from the point of view of CO ₂ release.

US 5,817,899 discloses hydrogenated olefin dimers having improved low temperature properties as lubricants. The dimerization takes place under BF ₃ catalysis. Boron trifluoride catalysts lead to an isomerization of the starting olefins. Thus, many possibilities of linking arise and even the preparation of dimers or trimers leads to a large number of isomeric olefins, which can then be hydrogenated to the corresponding paraffins. Thus, no defined structured paraffins are obtained, but mixtures containing a plurality of skeleton isomers.

In particular, in cosmetic applications, however, substances are preferred which have a defined structure and high uniformity and whose purity can be analyzed well by current methods. Linear paraffins are such defined compounds. The purity can be easily determined by gas chromatography and any impurities are easily identifiable. However, the linear paraffins have the disadvantage that they crystallize easily and have a melting point of +6 ⁰ C even at a chain length of 14 carbon atoms. For applications in which crystallization of a linear paraffin from a formulation would lead to problems, it is necessary to switch to branched paraffins.

However, known iso-paraffins are often complex mixtures of products and a structure elucidation is associated with considerable effort. In addition, fluctuating process parameters in the manufacturing process may result in changing product compositions, and undesirable product contaminants may be hidden in a simple gas chromatographic analysis.

There is therefore a need for iso-paraffins which do not have these disadvantages and are present as defined-structured compounds.

US 4,827,064 describes chromium-containing catalysts for the preparation of polyalphaolefins (PAO). The use of these special catalysts avoids isomerization of the starting olefin and gives increased viscosity index (HVI-PAO) PAOs. Analysis of the dimer and trimer fractions shows that although paraffins with defined structures are obtained, the insertion of the alpha olefin also takes place with undesirable regioselectivity leading to a linear dimer paraff. The dimer fraction of 1-decene oligomerization contains, in addition to the desired 9-methylnonacosane, 28 to 73% of n-eicosans. DE 69626882 T2 (corresponding to US Pat. No. 5,817,899) describes the disadvantages of a too high linear paraffin content in polyalphaolefins.

The production of PAOs requires a source of linear alpha-olefins. The short-chain olefins originate from cracking processes of the paraffins; the medium or long chain alpha olefins from ethylene oligomerization processes, all of which are raw materials or derived products of the crude oil.

Due to the limited availability of crude oil, a trend towards renewable resources has developed. Especially in cosmetic applications there is a trend towards natural products. The object of the invention is to provide a process for the preparation of structured paraffins which, on the one hand, avoids the disadvantage of undesirable by-product formation as in polyalphaolefin production and, on the other hand, opens up a new raw material source, in particular that of renewable raw materials.

The object is achieved by the method according to claim 1 and the use according to claim 11, preferred embodiments are subject of the dependent claims or described below.

The base-catalyzed oligomerization of fatty alcohols leads to a mixture of defined structured alcohols, in particular dimer and trimeralcohols, by dehydration in defined structured olefins or after subsequent hydrogenation in paraffins of the formula

überführt werden, wobei n für 0 bis 2 und R für H oder ein Kohlenwasserstoffrest mit 2 bis 16 Kohlenstoffatomen steht.

where n is 0 to 2 and R is H or a hydrocarbon radical having 2 to 16 carbon atoms.

The fatty alcohol used may be both synthetic in nature, but is preferably made from renewable resources, for example by fatty acid or fatty acid ester hydrogenation.

An advantage of using native raw material sources, especially for longer-chain alcohols, is the higher linearity of the alcohols obtainable from the respective esters, this applies in particular to alcohols having 16 or 18 and more carbon atoms.

The oligomerization of fatty alcohols to monohydroxy alcohols is known and probably leads to an aldehyde intermediate and subsequent aldol condensation. The regioselectivity of the condensation is dictated by the alcohol / aldehyde functionality and selectively leads first to a 2-alkyl branched dimer, which in turn can react to trimers, tetramers, etc. The given mechanism of oligomerization explains the increased regioselectivity compared to the chromium-catalyzed olefin oligomerization, where the olefin can insert into the carbon-metal bond in two ways (1,2- and 2,1-insertion).

The purification of the crude mixture is not absolutely necessary, but can be carried out both at the stage of the alcohols and during one of the subsequent reaction steps of the olefin or paraffin stage. The mixture is preferably distilled into different fractions, e.g. As a linear monomer fraction and a branched oligomer fraction, separated. It is also possible to isolate a dimer fraction or trimer fraction from the branched products.

The dehydration of the fatty alcohols is preferably carried out in the presence of acidic homogeneous or heterogeneous catalysts in batch reactors or continuously operated fixed bed reactors in the gas or liquid phase. Al ₂ O ₃ , SiO ₂ or their mixed oxides can be used as catalysts, in particular in a heterogeneous fixed bed reaction on corresponding shaped bodies, in particular spheres, extrudates or granules. Dehydration with Al ₂ O ₃ is preferred over dehydration with SiO ₂ or Al / Si mixed oxides, because the products prepared with the latter catalysts contain higher proportions of skeletal isomers. Preference is given to catalysts having a purity of greater than 99% by weight of aluminum oxides, based on the totality of all dehydration-active metals / metal compounds of the catalyst composition.

Preferred reaction conditions and catalysts for the dehydration are described in WO 2004/078336 A2 and lead in the gas phase dehydration preferably to the alpha-olefins. The liquid-phase dehydration can be carried out under the same reaction conditions as disclosed in WO 2004/078336 A2, but at a pressure of 1 to 3 bar. The liquid-phase dehydration can increasingly lead to mixtures of alpha and internal olefins by subsequent isomerization of the double bond. However, since the olefins are subsequently hydrogenated to paraffins, both dehydration routes can be used equally. The disclosure of WO 2004/078336 is hereby expressly made the disclosure content of the present application with regard to the conditions of dehydration and / or the catalysts. The hydrogenation is effected according to known methods, preferably on nickel-containing fixed-bed catalysts at temperatures of 20 to 200 ⁰ C and pressures of 1 to 50 bar.

The invention will be explained in more detail below with reference to examples of the manufacturing process and selected applications. The percentages in the examples mean wt%, unless expressly stated otherwise.

Example 1: Oligomerization of decanol

12 kg of 1-decanol (Nacol 10-99 ex Sasol) were admixed with 3 mol% potassium hydroxide under nitrogen in a 20 l flat-bottomed flask equipped with a stirrer and heated on a water separator. The progress of the reaction could be traced to the amount of water separated. After about 4 hours, catalytic amounts of zinc octanoate (100 ppm) were added. After a reaction time of 9 hours, the formation of water slowed down and the product was cooled to 20 ° C. The separation of the basic catalyst was carried out by means of flash distillation. Subsequently, the monomer was distilled off via a column and the bottom hydrogenated over Raney nickel (use 100 g of alloy) at 20 ⁰ C within 16 h with hydrogen. The product was then filtered through a 0.2 micron polyamide filter and the methanol required for washing and slurrying the catalyst removed on a rotary evaporator. There was obtained an alcohol mixture containing as main products 2-octyldodecanol (Dirner alcohol) and 2,4-Dioctyltetradecanol (trimer-alcohol).

This experimental procedure exemplifies a base-catalyzed oligomerization of fatty alcohols. After the reaction, a crude alcohol mixture consisting predominantly of monomer, dimer, trimer and small amounts of tetramer alcohols is obtained, which can be freed from the base both by distillation and by neutralization. Depending on the experimental condition, the product distribution can be varied.

Example 2: Dehydration and hydrogenation of decanol dimers (2-octyldodecanol) to produce 9-methylnonadecane

500 g of 2-octyl-decanol (ISOFOL 20 ex Sasol, purity 97.6%), 100 g of alumina spheres (purity Al ₂ O ₃ > 99%) and 20 mL of toluene were heated to 270 ° C. in the water separator over the course of 4 h and 2V Held between 270 ° C and 279 ° C for ₂ h. In this case, 29 mL of reaction water could be separated. The toluene was separated after filtration on a rotary evaporator. 100 g of the obtained olefin were hydrogenated in a Parr autoclave in the presence of 11.4 g of a nickel catalyst (HTC 400, Johnson Matthey) at 122 ^° C. and 20 bar. Filtration gave a 9-methylnonadecane with a purity of 95.8%. The physical data are shown in Table 1.

Example 3: Dehydration and Hydrogenation of Decanol Trimers (2,4-Dioctyltetradecanol) to Make 9-Methyl-ll-octylheneicosane?)

1200 g of decanol trimer (61.7% 2-Dioctyltetradecanol + 25% unsaturated trimer alcohol), 240 g of alumina spheres (purity Al ₂ O ₃ > 99%) and 50 mL of toluene were heated to 298 ° C within 3 h in a water separator. In the process, 33 mL of water of reaction could be separated. The toluene was separated after filtration on a rotary evaporator. 923 g of the resulting olefin were hydrogenated in a 2L Hofer autoclave in the presence of 46.7 g of a nickel catalyst (HTC 400) for 6 h at 140 ° C and 20 bar. After filtration, 9-methyl-1-octylheneicosan was obtained with a purity of 61.3%. Since trimer alcohol was still detected in the final product, the dehydration over the alumina catalyst was continued again. After 2 h at 294 ° C., a further 3.2 ml of reaction water were precipitated. After renewed hydrogenation over HTC 400, the 9-methyl-l l-octylheneicosan could be obtained with a purity of 71.2% in addition to 17.5% of other branched C ₃₀ paraffins. The physical data are shown in Table 1.

Example 4: Dehydration and hydrogenation of dodecanol trimers (2,4-didecylhexadecanol) to produce II ~ methyl-13-decylpentaeicosan

1200 g of dodecanol trimer (49.4% 2-dioctyltetradecanol, 26.4% unsaturated trimer alcohol, 13.3% dimer alcohol), 240 g of alumina spheres (purity Al ₂ O ₃ > 99%) and 50 ml of toluene were added to the water separator heated to 299 ° C within 2 h. It was possible to deposit 32 mL of water of reaction. The toluene was separated after filtration on a rotary evaporator. 890.4 g of the resulting olefin were hydrogenated in a 2L Hofer autoclave in the presence of 44.5 g of a nickel catalyst (HTC 400) for 8 h at 135 ° C and 20 bar. After 6 h, the reaction was stopped and an additional 20 g of HTC 400 were added. After filtration, the l l-methyl-13-decylpentaeicosan was obtained with a purity of 48.2%. Since trimer alcohol was still detected in the final product, the dehydration over the alumina catalyst was continued again. After 2 h at 295 ^° C., a further 1.9 ml of reaction water were precipitated. After renewed hydrogenation over HTC 400, 11-methyl-13-decylpentaeicosane with a purity of 64.2% could be obtained in addition to 17.8% of further branched C ₃₀ paraffins and 12.7% branched C ₂₄ paraffins. The physical data are shown in Table 1.

Example 5: Dehydration and hydrogenation of tetradecanol to produce tetradecane

In a continuously operated fixed bed reactor (DN 32) filled with 800 g of Al ₂ O ₃ balls, 0.5 to 2.5 kg / h of tetradecanol (NACOL 14-98 ex Sasol), which was obtained from vegetable raw materials, were added Temperatures of 230 ° C to 330 ° C and a N ₂ pressure of 2.5 to 3 bar dehydrated. The crude product was distilled via short path distillation (KWD 30) with a use of 10 kg / h at 0.5 bar and 103 ⁰ C and in continuously operated fixed bed reactor (DN 20) over 367 g HTC 400 with 0.3 to 2.4 L. / h at 80 to 120 ° C and 20 bar H ₂ pressure hydrogenated in the trickle bed procedure. The C ₁₄ paraffin content was 98.5%. The physical data are shown in Table 1.

Example 6: Dehydration and hydrogenation of dodecanol to produce dodecane

2575 g of dodecanol (NACOL 12-99 ex Sasol), 600 g of alumina spheres (purity Al ₂ O ₃ > 99%) and 60 ml of xylene were heated to 264 ^° C. over a period of 5 hours on a water separator. In the process, 234 mL of water of reaction could be separated. The xylene was partly discharged via the water separator. After filtration, the product was distilled at 10 to 30 mbar, with about 2-3% flow at 90 ° C were taken. Subsequently, the dodecene was removed at up to 125 ⁰ C bottom temperature. 1.5 L of the dodecene obtained were hydrogenated in a 5 L Büchi autoclave in the presence of 100 g HTC 400 6 h at 105 ° C to 120 ⁰ C and 20 bar. After filtration, the dodecane was obtained with a purity of 99.7%. The physical data are shown in Table 1.

Example 7a-7d: Dehydration of long-chain fatty alcohols

2474 g of 1-hexadecanol (NACOL 16-99 ex Sasol, purity 99.5%, based on renewable raw materials) were mixed in a 6-L flask with 500 g of Al ₂ O ₃ and 60 mL of xylene and up to 295 ° C heated for 4.5 hours on a water separator. This formed 180 mL of water. The resulting hexadecene was distilled in vacuo. A mixture of alpha and internal olefins was obtained. 685 g of the hexadecene were hydrogenated over a heterogeneous Ni-containing catalyst at 20 bar H ₂ pressure at 98 ⁰ C for 7 hours and filtered after cooling.

Fatty alcohols with chain lengths of C ₁₆ to C ₂₂ were reacted according to Example 7a and the following paraffins were obtained:

Example 8:

Example 7a was repeated but a synthetic fatty alcohol was prepared from

Ziegler process with a purity of 95.6% used as feed alcohol.

Example 9:

The hydrogenation step of Example 7a was repeated, but became a synthetic

Hexadecene (ex Chevron Phillips) with a purity of 94.2% used as feed olefm.

A comparison of the hexadecane purities, prepared on the basis of commercially available fatty alcohols or olefins, is summarized in the following table. Due to the use of a highly linear raw material based on renewable raw materials, highly linear paraffins could be obtained without complex isomer separation.

Die erhaltenen Paraffine zeichnen sich durch einen hohen prozentualen Anteil einer definiert strukturierten Hauptkomponente aus. Die Hauptkomponente im Dimer-Paraffm ist mono-methyl-verzweigt; die Hauptkomponente im Trimer-Paraffin dialkyl-verzweigt, wobei eine der Verzweigungen eine Methylgruppe ist. Die verzweigten Paraffine weisen einen niedrigen Pourpoint und einen hohen Viskositätsindex aus. In der folgenden Tabelle sind physikalische Daten ausgewählter Monomer-, Dimer- und Trimer-Paraffϊne dargestellt.

The paraffins obtained are characterized by a high percentage of a defined structured main component. The major component in the dimer paraffm is mono-methyl branched; the major component is dialkyl branched in trimer paraffin wherein one of the branches is a methyl group. The branched paraffins have a low pour point and a high viscosity index. The following table presents physical data for selected monomer, dimer and trimer paraffins.

Table: Physical data of selected paraffins prepared from monomer, dimer and trimer alcohols.

Important physical properties of emollients for use in the cosmetic sector are surface tension and spreading behavior. The following table shows these parameters for selected paraffins.

Table: Physical data of selected paraffins prepared from monomer, dimer and trimer alcohols.

In the following, example formulations for cosmetic applications are described.

OAV cream

Phase A and B are heated separately to 80 ⁰ C. Phase B is added to Phase A and dispersed. The emulsion is cooled to about 30 ⁰ C and vented before Phase C (preservative) is added. The composition and results of the measurements made are shown in the table below.

The "Bioparafϊne" prepared according to the invention can be used to substitute the available from other sources paraffins and show the same or better properties.

Claims

claims 1. A process for the preparation of paraffins or paraffin mixtures of the general formula I.

wherein n is equal to O ₅ 1 and / or 2 and R is H or a hydrocarbon radical with 2 to 16, in particular 4 to 12, carbon atoms, and the method comprises at least the following steps: (B) dehydration of fatty alcohols or mixtures thereof of the general formula II

where n and R have the above meaning, to olefins and (c) hydrogenation of the olefins to paraffins of the general formula I. 2. The method according to claim 1, characterized in that the dehydration of the fatty alcohols to the olefins is carried out in the presence of alumina. 3. The method according to at least one of the preceding claims, characterized in that the method further comprises the following step: (a) oligomerization of linear fatty alcohols having 6 to 22 carbon atoms to fatty alcohols of the general formula II with n at least equal to 1 and / or 2. 4. The method according to at least one of the preceding claims, characterized in that in step (a) fatty alcohols are used which are prepared by hydrogenation of fatty acids or their esters, in particular fatty acid methyl esters or wax esters, wherein the fatty acids obtained from esters of vegetable or animal origin are, in particular from palm oil, palm kernel oil, coconut oil, rapeseed oil, sunflower oil, and subsequent oligomerization to fatty alcohols of the general formula IL 5. The method according to claim 3 or 4, characterized in that the method further comprises the steps of: (a.l) Distilling the crude product of the oligomerization into a linear fraction containing the linear fatty alcohol with n equal to 0 and a fraction containing the branched alcohols with n equal to 1 or 2 and exposing one or both fractions containing branched alcohols to the step of dehydration. 6. The method according to at least one of claims 3, 4 or 5, characterized in that the method further comprises the steps of: (a.2) Distillation of the fraction containing the branched alcohols into a dimer and a trimer fraction. 7. The method according to claim 5 for preparing a paraffin mixture containing the monomethyl-branched compound with n = 1 in a concentration of at least 50 wt.%, In particular at least 75 wt.%, Based on all paraffins. 8. The method according to claim 5 for preparing a paraffin mixture containing the bifunctional compound with n = 2 in a concentration of at least 50 wt.%, In particular at least 75 wt.%, Based on all paraffins. 9. The method according to at least one of the preceding claims, characterized in that the resulting paraffin mixture has a pour point of less than -10 ° C. 10. Use of paraffins or paraffin mixtures of the formula I,

wherein n is 0, 1 and / or 2, in particular with n = 1 or 2, and R is H or a hydrocarbon radical having 2 to 16, in particular 4 to 12, carbon atoms, in cosmetic formulations, in textile or leather auxiliaries, in lubricating compositions or in formulations for paints and varnishes. 11. Use according to claim 10, characterized in that the paraffins can be prepared by one of the methods according to claims 1 to 9, in particular using fatty acids from esters of vegetable or animal origin according to claim 4. 12. Use according to claim 10, characterized in that the paraffins are used as spreading agents in emollients for cosmetic formulations, in particular n-dodecane and / or n-tetradecane. 13. Use according to claim 10 or 12, characterized in that the paraffins are used at least in part as a replacement for silicone oils and is preferably completely dispensed silicone oils in the cosmetic formulations.