KR20040037128A - Phthalic acid alkylester mixtures with controlled viscosity - Google Patents

Abstract

The present invention relates to phthalic acid alkylester mixtures whose viscosity is controlled by the composition of isomerically pure alcohols from which the mixture can be prepared. The invention also relates to the use of said mixture.

Description

Phthalic acid alkylester mixtures with controlled viscosity

The present invention relates to mixtures of phthalic acid esters and the use thereof, the viscosity of which can be adjusted via the contribution of each isomeric alcohol from which phthalic acid esters can be prepared.

Phthalic acid esters are widely used as plasticizers for plastics, for example PVC. Plasticizers can be defined as materials that provide increased flexibility, ductility and processability to materials, particularly plastics. Alan S. Wilson, Plasticizers, The Institute of Materials, 1995, ISBN 0 901716 76 6, p. One]. Although not limited to this, plasticization of PVC is particularly interesting.

Almost always for 100 years the development of new plasticizers with multifunctional esters has continued. The most frequently used esters are esters of polybasic carboxylic acids and monoalcohols. Examples of the polybasic aromatic carboxylic acid or anhydrides thereof used are phthalic acid and isophthalic acid, trimellitic acid, pyromellitic acid and terephthalic acid. Inorganic acids are also used, the best known example being phosphate esters. In the case of these carboxylic acids or their anhydrides or phosphate esters also acid chlorides such as POCl ₃ are generally monoalcohols such as ethanol, butanol, isobutanol, n-amyl alcohol, isoamyl alcohol, heptanol React with 2-ethylhexanol or 2-propylheptanol. The higher alcohols which are preferably used include isomer mixtures obtained by oligomerizing olefins having 3 to 5 carbon atoms and subsequent hydroformylation and hydrogenation of the resulting aldehyde. Industrial examples are isoheptanol, isooctanol, isononanol, isodecanol and isotridecanol. Oligomerization of ethylene also provides access to linear compounds known as α-olefins and provides a mixture of linear alcohols and low branching alcohols in hydroformylation. Examples of alcohols produced industrially in this way are nonanol and undecanol and mixtures thereof. Straight chain alcohols can be accessed from the chemistry of fats or via synthetic routes that increase the molecular weight and start from ethylene, examples of which are known as Ziegler alcohols. Finally, mention may be made of industrially used cyclic alcohols such as cyclohexanol, benzyl alcohol, phenol, cresol and xylol.

Rather than reacting polybasic carboxylic acids with monoalcohols, an alternative approach may be employed that provides a plasticizer by reacting polyhydric alcohols with monocarboxylic acids. Examples of polyhydric alcohols are neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol, ethylene glycol and oligomer di-, tri- and tetraethylene glycols thereof, glycerol, butanediol, hexanediol and the like. Sugar alcohols can also be used for this purpose. Carboxylic acids as used herein are compounds similar to the alcohols mentioned, ie carboxylic acids having 2 to about 13 carbon atoms. Examples are acetic acid, butyric acid, valeric acid, heptanoic acid, nonanoic acid and also isomeric mixtures such as isoheptanoic acid, isooctanoic acid, isononanoic acid, isodecanoic acid and isotridecanoic acid in triacetin.

Compounds having both acid and alcohol functionality can be used. The best known example is citric acid having three carboxylic acid groups and one alcohol group. Esterification of carboxylic acid groups with monoalcohols provides useful esters, and alcohol groups can be esterified with carboxylic acids such as butyric acid or acetic acid.

For the sake of completeness it should be mentioned that esters of monoalcohols and monocarboxylic acids are used as plasticizers in certain cases when their boiling points are high enough, examples being stearic or lauric esters.

However, this is not comprehensive enough. For example, combinations of polyhydric alcohols with polybasic carboxylic acids can also be used as plasticizers. An example is the combination of diols and dicarboxylic acids to give low molecular weight polyesters, the terminal groups of which are esterified using monofunctional alcohols or carboxylic acids. The remaining alcohol group is esterified using monocarboxylic acid. Ether bonds can be used to increase the number of esterifiable groups, such as in di- and tripentaerythritol, with 6 and 8 esterifiable alcohol groups, respectively. This method is especially used when a high molecular weight plasticizer with a high polar content is desired.

Very generally, the objective is to process with low polarity with respect to their molar mass, high molar mass, low mobility in the material, low liquidity in the material in order to have a polarity sufficient to serve as a good plasticizer and to have the lowest possible volatility. It is to prepare a compound easily.

It should be mentioned that compounds having these properties or mixtures of compounds have, for example, synthetic lubricants, hydraulic fluids, and also other application sectors that are important as solvents in ointments, inks and the like. The term functional fluid is often used.

Using this method, it can be adjusted to esters of almost any use, but is limited by the resources required and the costs involved and also the availability of the raw materials. Thus, most of the possible combinations are either now out of the market or achieve only limited significance in place or are impractical. However, when the new process provides access to low cost raw materials, changes in attitude to the environment or new technical requirements call for new measures where circumstances change from time to time or where alternatives are found for products commonly used therein.

Briefly, the following description is limited to some selected examples of specific industrial feasibility from the PVC plasticizer application sector. However, the problems described below and their solutions can in principle be imputed to all of the esters mentioned.

problem

Easily, the most important ester class for plasticizers is phthalate. Within these, 2-ethylhexyl (also often known as the abbreviation "octyl") phthalate, DOP (dioctyl phthalate) or DEHP (diethylhexyl phthalate) are currently dominant. However, there is an increasing replacement with DINP (diisononyl phthalate), which has significant performance advantages such as lower volatility and lower mobility. Unlike stereoisomers, unlike DEHP, a single chemically defined material with obvious measurable properties, DINP is a mixture of many similar isomers of the same molar mass. This is the result of the origin of the isononanol used in the esterification process.

Isononanol is prepared by hydroformylating octene, which is produced by various methods. Commonly used feedstocks are industrial C ₄ streams which initially contain all isomeric C ₄ olefins with saturated butane and in some cases contaminants such as C ₃ and C ₅ olefins and acetylene-based compounds. Extractive distillation is used to obtain useful compound butadiene using, for example, NMP (N-methylpyrrolidone). As an alternative, butadiene can also be converted to 1- and 2-butene via selective hydrogenation, such as, for example, in the SHP-CB process under Oxenogeembe. In both cases, the product is in fact a C ₄ stream in which the olefins still present are isobutene and 1- and 2-butene, often referred to as “raffinate I”. Oligomerization of such olefin mixtures provides mainly octenes with higher oligomers, such as C ₁₂ and C ₁₆ olefin mixtures. The C ₈ cut is called “codibutylene” and is already used for the preparation of isononanol for plasticizers.

Today, isobutene is generally removed in the second stage of the process by acidic catalysis, for example by reaction with methanol using an acidic ion exchanger. This gives the important fuel additive methyl tert-butyl ether (MTBE) and the C ₄ stream known as "rapinate II" and is virtually free of isobutene. It may also use other alcohols such as ethanol instead of methanol. In this case, ethyl tert-butyl ether, ETBE is obtained. Selective removal of isobutene is also possible using water instead of alcohols, tert-butyl alcohol TBA is formed, which is again an important compound used in industry. Degradation of TBA in the reversible reaction gives high purity isobutene. In all the variants described, there remains a C ₄ stream in which the still present virtual material known as “raffinate II” is 1- and 2-butene with saturated butane.

Useful material 1-butene can be obtained from raffinate II, which may optionally be isobutane used as fuel gas, for example as a comonomer for polyolefins. This gives a weak C ₄ stream, Raffinate III for 1-butene. Raffinate II or Raffinate III can be used as raw material for oligomerization. Here, there are various approaches used industrially. The previous oligomerization process is operated with an acidic catalyst on the support, for example phosphoric acid or acidic zeolite (process variant A). The product here is octene consisting essentially of dimethylhexene. Newer methods, such as the DIMERSOL process, operate on soluble Ni complex catalysts. These give an octene mixture with a high proportion of 3- and 5-methylheptene together with n-octene and dimethylhexene (process variant B). The best modern process utilizes the high selectivity of certain supported Ni catalysts, and the octol (OCTOL) process from Oxenome GmbH is well known. The octene mixture obtained has the lowest degree of branching which is a particularly useful factor for plasticizer alcohol applications (process variant C). The table below provides approximate values for the composition of each product obtained since the exact composition depends on the catalyst, temperature, retention time, conversion and other conditions used. However, this clearly shows that the isomer composition obtained differs depending on the process. Raffinate II or III is provided.

A acid catalysis B dimerazole C octol n-octene 0% 6% 13% Methylheptene 5% 59% 62% Dimethylhexene 70% 34% 24% Etc 25% One% One%

Another method of obtaining octene is oligomerization of isobutene. The main product is a mixture of 2,4,4-trimethyl-1-pentene and 2,4,4-trimethyl-2-pentene. Oligomerization of ethylene by Ziegler catalysis or the SHOP process is another route to higher olefins and forms linear terminal olefins with a wide range of carbohydrate distribution. In particular C ₈ cuts can be obtained and these cuts can also be obtained from the Fischer-Tropsch process. Finally, sometimes the opportunity to separate suitable carbon number hydrocarbons from the naphtha stream is used. These mainly contain saturated alkanes and are converted to olefins by dehydrogenation.

An entirely different method is oligomerization of a cut comprising a crude unseparated olefin stream, such as C ₃ , C ₄ and optionally C ₅ olefins, such as occurs during the cracker process. Under acidic oligomerization, these streams provide a mixture of all imaginable combinations of these olefins, i.e. hexene, heptene, octene, nonene, decene and the like, which are cracked into carbon number cuts known as polygas olefins. The main product obtained is a relatively highly branched internal olefin.

In total, there are a variety of processes that provide suitable chain length olefins for oxo reaction / hydrogenation to provide plasticizer alcohols. Depending on the process, the isomeric mixtures obtained have very different branches, unbranched or tribranched or multibranched, and terminally to almost exclusively have various double bond positions from the inside.

The next step in the oligomerization process is hydroformylation, ie the reaction of olefins with carbon monoxide and hydrogen known as synthesis gas to give aldehydes. Many industrial variations can be used. Hydroformylation with catalytic hydrocobalt carbonyl is usually used at 170 to 190 ° C. under 200 to 300 bar (high pressure Co process, HPCo). Co catalysts modified with alkyl phosphines are also used industrially (Co ligands). Another known process is operated with rhodium as catalyst at 120-130 ° C. under 100-300 bar instead of cobalt (HPRh). The three processes differ markedly in the isomeric composition of the product. For example, HPCo oxo reactions of internal linear octenes provide about 50% of linear n-nonanol (n / i-1) with internal isomers from the oxo reaction, whereas oxo reactions with ligand-modified Co are about 80% (n / i to 4) and HPRh oxo reaction provides about 20% (n / i to 0.25). Similar considerations also apply to the oxo reaction of branched olefins.

Although the empirical formula is, for example, the same as C ₈ H ₁₆ for octene, the olefin cuts used industrially contain very different structures and double bond isomers. When the same olefin cut is used, the degree of branching in the plasticizer alcohol obtained through oxo reaction / hydrogenation is very diverse as a function of the oxo process used. In addition, even in the case of a fixed blend of one oxo process and one oligomerization process, the isomeric composition changes are derived from the raw materials used, eg changes in operating conditions, control of conversion to the required manufacturing program and many other factors. This results in a change in the composition of the C ₄ cut.

Thus, the isomeric composition of the resulting plasticizer alcohols varies within wide limits. However, it is known that the physical properties and performance of plasticizers are very dependent on their structure. As an example of the physical properties, the viscosity of the phthalate measured at 20 ° C. is given below. Specifically, the phthalate (DINP) of isononanol when linear olefins are used has a viscosity range of 50 to 60 mPa · s, while the known DINP grade is 160 to 170 mPa · s when codibutylene is used. The viscosity of the polygas octene DINP grade is 90 to 110 mPa · s. Using raffinate II or III in the octol process, the alcohol obtained has a phthalate having a viscosity of 72 to 82 mPa · s when the oxo reaction used is a high pressure Co process. The same starting material using the Rh catalyst gives a plasticizer having 90 to 100 mPa · s.

The following precautions are inherently limited to several variations of octene-based plasticizers, but the skilled artisan readily recognizes that problems always exist when the mixtures and especially the isomeric mixtures are used to prepare esters which are functional fluids, and plasticizers It is considered as a subgroup of functional fluids.

The performance required by the ester to fulfill its action is particularly complex. In use as lubricants, for example, viscosity, dropping point, viscosity dependence on temperature and many other factors play an important role. Factors for plasticizers are electrical properties, especially at low temperatures, in flexible action and plasticizer viscosity and in the use of cable sheaths. All of these properties depend on the structure of the material used and therefore the isomeric composition of the material used.

There is a qualitative rule for structure dependence of performance. See, eg, Alan S. Wilson, Plasticizers, The Institute of Materials, 1995, ISBN 0 901716 76 6, pp. 135-136 describe phthalate properties as a function of the overall carbon number, ie the molar mass and the degree of branching, in particular the isomer composition. At the same molar mass, for example, increasing the degree of branching in particular results in:

Negative effect

Viscosity increase

Increased vapor pressure, thus higher volatility

Lower plasticizing levels

Resistance to lower heat and light

Positive effect

Better PVC compatibility

Less mobility

Greater history

Lower biodegradability (during product use)

Higher electrical resistance

It is directly clear that this is not the best plasticizer and must be compromised for each application. For example, when plasticizing action is very important, the plasticizer which is the lowest possible branching is preferable. In contrast, when producing PVC cable sheaths, it is desirable to use products with a somewhat higher degree of branching, since they have a better electrical thermal action.

See Brian L. Wadey, Lucien Thil, Mo A. Khuddus, Hans Reich; The Nonyl Phthalate Ester and its Use in flexible PVC, Journal of Vinyl Technology, 1990, 12 (4), pp. 208-211 clearly demonstrated with reference to some synthetically prepared single isomers of DINP whether the important properties depend on the structure of the ester.

In summary, performance depends on the structure of the phthalate, which partly depends on the structure of the alcohol and partly on the structure of the base olefin. Another complex factor is that these compounds are prepared in the form of isomeric mixtures. Therefore, it is desirable to modify or formulate the composition of the mixture to obtain a mixture with the described properties.

The main difficulty is that various tests are required to assess the performance suitability of a single material. Taking phthalate as a plasticizer for PVC as a single example, a representative phthalate sample should first be prepared in the laboratory from the alcohol mixture used. Test plaques often have to be made of PVC with two or more concentrations of plasticizer, and actual standard tests are performed on them. This is very complicated and takes days or weeks. In lubricant applications, the required resources are still very expensive, for example if the engine test has to be carried out over several weeks.

As mixing specifications are developed, products with certain properties can be made in the manufacturing process. For example, the viscosity of the lubricant should be kept within a narrow range so as to remain within the desired viscosity classification. Examples for plasticizers should be that the plasticization action is kept constant or the electrical resistance is at a minimum so that the processor using the plasticizer is not constantly forced to control the mixing specification. However, as described above, continuous manufacturing control through performance testing is impossible even if the current costs incurred are ignored.

Theoretically, the problem can be solved by keeping the isomer composition exactly constant, but this cannot be achieved in practice. Crackers do not operate for the purpose of feeding a constant composition C ₄ stream, but provide ethylene, propylene, petroleum spirits or other bulk products. In fact, the composition of the C ₄ streams obtained from the crackers always depends greatly on the composition of the raw materials used and the mode of operation. The problem is generally more difficult to handle than when C ₄ streams are obtained from different crackers as in the case of large scale production.

Thus, the raw materials used at the starting point in themselves inevitably change the composition of the product and thus the isomer distribution and the performance. As discussed above, other changes in product composition are performed in subsequent oligomerization and hydroformylation steps, eg, through changes in operating conditions or aging of the oligomerization catalyst. The problem is most severe in the independent ester producers who obtain the alcohols used, since the products can come from different oligomerization and oxo processes. It may also be mentioned that there is a DINP grade with a viscosity of about 50 to 170 mPa · s at 20 ° C. depending on the raw materials used to prepare isononanol used as esterification alcohol, oligomerization process and hydroformylation process. have. Isolated Example DINP demonstrates that the fundamental problem or similar applies, of course, to all fluids used as functional fluids, especially when isomeric mixtures of alcohols or carboxylic acids are used.

As discussed above, in principle, isomeric concentration variations can be used to control products for various application sectors, but for economic reasons it is desirable to operate the plant consistently. Even if the desired properties of the product ignore the problems that must be considered initially, this is very costly and time consuming and often leads to different production modifications resulting in different product modifications. Thus, the aim is to produce standard products with the most consistent properties possible, and the products include the widest possible range of applications. However, consumer requirements are becoming more stringent, and increasing consumer policy requires a response to consumer desires, which inevitably implies the manufacture of certain products with standard products.

purpose

Therefore, the aim is to prepare phthalate mixtures with specific properties from alcohol mixtures of a wide variety of compositions, the properties of which can be controlled in a simple way through the composition of the alcohols.

Ideally, it should be found that the performance of the final product (phthalate mixture) is predicted during the hydroformylation of aldehydes prepared from olefin isomeric mixtures, for example, before the preparation of the critical precursor is complete. This should be possible without long performance tests on the final product (eg preparation of carboxylic acids by alcohol and oxidation by hydrogenation, preparation of esters, preparation of test plaques using plasticized PVC, etc.).

Achievement of purpose

The viscosity of the phthalate esters depends on the structure and isomer composition of the alcohols used for the esterification, respectively. This is related to performance variables such as low temperature flexibility and electrical resistance. If sufficient measurements are available, they can be described using theoretical equations or even simple empirical equations.

Thus, viscosity measurements, particularly simple measurements, of single phthalic acid esters can provide conclusions regarding other aspects of performance. However, the problem is that it cannot be measured until a finished ester, for example DINP, is used. It is too late to act on the alcohol composition.

In principle, the viscosity of a mixture of isomeric compounds can be achieved using simple mixing rules with a single component. VDI-Warmeatlas [VDI heat atlas], VDI Verlag, seventh extended edition, 194, section Da 30 show the following.

In the above formula,

η is the viscosity of the mixture,

η _e is the viscosity of a single component (phthalate),

x _e is the mole fraction of the single component (phthalate).

Determination of the viscosity of a single component (phthalate) and determination of the isomeric composition (phthalate) are therefore suitable means of checking whether product properties remain constant. However, this is actually impossible due to the large number of isomers, since the cost of testing them following synthesis or separation from the reaction mixture is not acceptable using the means currently used.

The following list provides the most important isomers of isononanol used to prepare DINP and is prepared by the oxo reaction of an octene mixture prepared by oligomerizing 2-butene. The composition can be represented essentially as follows and has 14 isomers ignoring stereoisomers: n-nonanol, 2-methyloctanol, 2-ethylheptanol, 2-propylhexanol, 4-methyloctanol , 3-ethylheptanol, 6-methyloctanol, 2,3-dimethylheptanol, 2-propyl-3-methylpentanol, 2-ethyl-4-methylhexanol, 2,5-dimethylheptanol, 4 , 5-dimethylheptanol, 2,3,4-trimethylhexanol and 2-ethyl-3-methylhexanol.

If the raw materials used initially also contain isobutene, for example, many additional isomers, for example 3,5,5-trimethylhexanol, 3,4,5-trimethylhexanol and 3,4 , 4-trimethylhexanol and the like are present.

When alcohols are esterified using dibasic polycarboxylic acids, for example phthalic acid, they occur when the alcohol used is composed of one single isomer only when one single compound is produced. For example, when phthalic acid is esterified using n-nonanol, di-n-nonyl phthalate is produced. In contrast, when the esterified alcohol consists of two or more isomers, the product produced in the esterification of phthalic acid is, for example, phthalates where the two alkyl radicals are the same or different. Thus, using isononanol having the 14 isomers mentioned above, 14 phthalates with the same alkyl group can be produced and 91 (14.13 / 2) phthalates with 2 different alkyl groups can be produced. have. Thus, when ignoring stereoisomers, a total of 105 different phthalates can be formed.

In the case of compounds, for example esters of tribasic trimellitic acid or tetrabasic pyromellitic acid, the number of isomers is anhydrous. One of the isomers has to be tested, the analytical separation is complex and time consuming, and so is the preparation of suitable specimens for viscosity measurement.

It has surprisingly been found that the viscosity of the isomeric mixtures of esters of this type is related to the composition of the esterified alcohols used in the case of polycarboxylic acid esters and the composition of the carboxylic acid used to esterify the polyol, respectively.

The mixing rule cited above cannot be used for the viscosity of the ester as it is only the composition of the esterified alcohol and the carboxylic acid, respectively, rather than the actual composition of the ester being inserted. The result is the viscosity parameter of a single isomer as a contribution to the viscosity of the ester mixture obtained by esterification into multiple isomers. These values also naturally include the effect of the interaction of single isomers in the ester.

If the molar fractions of the single alcohol components used in the alcohol mixture obtained by esterifying the phthalate mixture are the same, the ester mixture consisting of only phthalates having the same alkyl radicals, together with the phthalates having the same alkyl radicals and also having isomeric alkyl radicals, It cannot be foreseen to have almost the same viscosity as the phthalate mixture present.

Alternatively, when all isomers present in the alcohol mixture are separated and esterified with phthalic acid, and when the various phthalates are mixed in the ratio at which the alcohol is present in the alcohol mixture, the viscosity of the phthalate mixture obtained is obtained from the direct reaction of the alcohol mixture with phthalic acid. Approximately the same as the resulting mixture.

This result is surprising because the number of phthalate mixtures that can result during the direct esterification of the alcohol mixture with phthalic acid is much higher than that which results during the esterification of a single component by mixing in a specific ratio, as described above. This means that the isomer composition of the base alcohol mixture is not the actual number of phthalate isomers in the important phthalate mixtures.

Accordingly, the present invention provides a mixture of isomeric dialkyl phthalates having a particular viscosity prepared by esterification of phthalic acid or phthalic anhydride with a mixture of isomeric alkyl alcohols of particular carbon number, wherein the viscosity of the phthalic ester mixture is It is controlled through the composition of the isomeric alkyl alcohols according to equation (I) and their viscosity parameters.

In Equation I above,

η is the viscosity of the dialkyl phthalate mixture,

x _i is the mole fraction of isomericly pure alcohols,

η _i is the viscosity parameter of the isomerically pure alcohol in the dialkyl phthalate mixture.

The viscosity of the mixture depends on the carbon number of the isomeric alkyl alcohol used for the esterification. The viscosity or preferred range of the invention is as follows:

Carbon number of isomeric alkyl alcohol Viscosity of dialkyl phthalate mixture (mPas) (20 ° C) The present invention Desirable range Particularly preferred range 4 19-44 19-44 19-44 5 24-50 24-50 24-50 6 28-80 28-70 28-60 7 33-100 33-70 33-65 8 39-130 39-110 39-100 9 45-200 45-165 45-120 10 52-400 52-330 52-200 11 61-400 61-380 61-350 12 66-400 66-380 66-350 13 70-400 70-380 70-350 14 74-400 74-380 74-350

If a mixture of isomeric dialkyl phthalates is prepared by mixing two dialkyl phthalate mixtures to a specific viscosity η (where, in limited cases, isomerically pure phthalic esters may be used instead of the mixture), a mixture of two components The content can be calculated according to formula (II), if the mole fraction of the isomeric alcohol from which the phthalate mixture is based is known.

In Equation II above,

η is the viscosity of the dialkyl phthalate mixture after two component mixing,

x _i1 is the mole fraction of isomers in alcohol mixture 1 obtained from saponification of phthalate mixture 1,

x _i2 is the mole fraction of isomers in alcohol mixture 2 obtained from saponification of phthalate mixture 2,

η _i is the viscosity parameter of the alcohol isomer,

a is the proportion of phthalate mixture 1 in the two component mixture,

(1-a) is the ratio of phthalate mixture 2 in the two component mixture,

a / (1-a) is the mixing ratio of two components.

Similar to Equation II, a calculation method can be set for the mixing of two or more phthalate mixtures. For example, the equation applicable to the viscosity of the phthalate mixture prepared from the phthalate mixture is Equation III.

In Equation III above,

a + b + c is 1,

a, b and c are the proportions of the three components in the total mixture.

Accordingly, the present invention relates to certain viscosity isomeric dialkyl phthalates prepared by mixing isomerically pure dialkyl phthalates and / or dialkyl phosphate mixtures in which the alkyl esters have the same carbon number and have carbon numbers corresponding to their viscosity. Wherein a mixture of isomeric dialkyl phthalates has a viscosity and composition according to formula IV (Equations II and III are the special cases of formula IV generally applied).

In Equation IV above,

Is 1 (0 ≦ a _j ≦ 1),

n is the number of components in the mixture,

m is the number of alcohol isomers that are the source of the final mixture,

η is the viscosity of the dialkyl phthalate mixture after component mixing,

x _ij is the mole fraction of the particular isomer i in the alcohol mixture j obtained from saponification of the phthalate mixture j,

η _i is the viscosity parameter of the particular alcohol isomer i,

a _j is the mixture content (weight ratio) of component j (phthalate mixture) in the final product.

With regard to its chain length and viscosity and the preferred ranges, the above description can also be applied.

Equations II to IV also indicate that if one wants to prepare an alcohol mixture from two or more alcohol mixtures (components) that differ in the isomer composition (the nature and also the quantitative ratio of the isomers) in order to prepare a phthalate mixture having a particular viscosity, Can be applied to calculations.

The present invention also provides a process for the preparation of mixtures of isomeric dialkyl phthalates having the stated viscosity by blending phthalic acid esters or alcohols before esterification.

The isononyl phthalates of the present invention prepared from alkyl alcohols having 9 carbon atoms are prepared using a mixture of isomeric alkyl alcohols which is a mixture of nonanols prepared by mixing isomerically pure nonanols or nonanol mixtures with n-nonanol. Can be obtained.

As an alternative, a mixture of isomeric alkyl alcohols, which is a mixture of nonanol prepared by mixing isomerically pure acid nonanol or nonanol mixture with 3,5,5-trimethylhexanol, can be used.

When phthalic acid esters are mixed, for example dinonyl phthalate, the isomerically pure dinonyl phthalate or dinonyl phthalate mixture may be mixed with di (3,5,5-trimethylhexyl) phthalate or di (isononyl) phthalate. You can mix.

Suitable blending of minor ingredients allows the preparation of any product whose viscosity is within these ranges. For example, alcohol n-nonanol or 3,5,5-trimethylhexanol can be used to adjust the viscosity of DINP grades of about 45 to about 110 mPa · s, in the first example a product having good low temperature flexibility And in the second case a product having a lower low temperature flexible action but having increased electrical resistance.

Easily adjustable viscosities allow the phthalic acid ester mixtures of the present invention to be versatile, which can be used as components in plasticizers, hydraulic fluids, lubricants or lubricants for plastics, in particular PVC.

Determination of viscosity contribution from a single component

First, it may be desirable to analyze or analyze all isomers that include all trace components, as they can dramatically increase the cost. Here the method takes any unknown residue in its entirety and treats it as a virtual component. If this unknown residue is not too large, for example less than 10% or preferably less than 5%, the error is not unacceptably large. For example, many measurements of unknown residues of several% are covered by an error of +/- 2 mPa · s in the final product.

Second, it can sometimes be a problem due to autocorrelation of isomers. For example, when 2-propylhexanol is produced during the oxo reaction of internal n-octene, there is always some content of 2-ethylheptanol and 2-methyloctanol and high levels of autocorrelation of these isomers. Cause. If these isomers are not more clearly distinguished by other measurements, for example distillation, these autocorrelation components are taken together with a single component. If the described measurement cannot eliminate autocorrelation, the accuracy may be very small since it may be stronger in the actual manufacturing system. Thus, treating two or more components of this type with a single component is fully acceptable and justified.

Surprisingly, not all components need to be separated to measure the hypothetical contribution to viscosity. Indeed, in the case of isononanol, up to 3 or 4 components can be taken together without exceeding the allowable error. On the other hand, the accuracy can be improved just as desired at a correspondingly high cost, especially if it is inevitable by mandatory requirements. However, it is not necessary to incur this cost. In fact, there may be a tradeoff between cost and accuracy.

As soon as the basic data is measured, the solution can be used to keep it within range. Since the effect of the components is known, the compositional change and thus the expected property change can be promised during the manufacturing process itself. The composition of the product remains precisely constant, and as described, it is not important that it is industrially impossible or possible at unacceptable costs. Rather, it is important that the performance of the final product is constant. In practice, the method is to provide components, isomer mixtures or defined alcohols for immediate use which are markedly deviated from the desired values.

The term "isomer" used hereinafter means a compound having the same empirical formula but different structure. Isomerically pure means that an ester or alcohol consists of a compound of one isomer (stereoisomers are regarded as one isomer in this regard), ignoring impurities of other isomers present and / or resulting from industrial processes do.

The phthalates of the present invention and methods for their preparation allow for rapid and automated control of the preparation at the precursor stage of the preparation of isononanol, for example by hydroformylation of a complex octene mixture followed by hydrogenation of a hydroformylation product, The isoindex and properties of the branch at are maintained during the hydrogenation of the aldehyde to obtain the corresponding alcohol and conclusions can be reached concerning the properties of the final product, eg DINP plasticizer, prepared therefrom. An example of a control method is a process gas chromatograph coupled with automated calculation of the expected viscosity of the plasticizer. This allows for automatic monitoring of product quality and expected end product performance, in which case it monitors the material variables of viscosity. However, since it has a regular correlation with one aspect of performance, important variables can usually be adjusted within a certain range. All that is needed to carry out a continuous adjustment is a single determination of the required measured value.

In practice the process is to produce a series of different mixtures with the largest possible isomer composition. Here, the problems mentioned earlier are, for example, octene mixtures of different compositions, for example commercially available olefins such as 1-octene, 4-octene, 2-ethyl-1-hexene or 2,4, 4-trimethylpentene (diisobutene) can be used regularly to solve the problem. The isomer mixture can also be prepared by dehydrating the alcohol on an acidic catalyst, for example by dehydrating 2-octanol or 2-ethylhexanol. One method of preparing dimethylhexene is acidic oligomerization of 1- and 2-butenes. All synthetic routes to make olefins can be used to obtain different starting olefins as possible.

The olefins are hydroformylated in various ways, for example using HPCo, HPRh or ligand modified Rh or Co catalysts. This provides a further distinction of isomer composition even if the starting olefins used are identical. Hydrogenation provides the desired alcohol, for example isononanol, having a relatively different isomeric composition. Further distinction can be achieved by careful distillation, yielding isomeric cuts with non-natural isomeric distribution. Of course, also other synthetic methods for preparing alcohols and aldehydes can be used.

The olefin feed stage for hydroformylation can also control the viscosity of the final product. For example, by adding a mixture of adjuvants, 1-octene or low branched octenes to lower the viscosity of the plasticizers subsequently produced from the mixture, or adding diisobutene or higher branched octene mixtures to increase the viscosity in a similar manner. Can be. In each case, the continuous analysis shows the isomer distribution achieved during the hydroformylation step of the oxo process, which can be converted by calculation to provide the required amount of adjuvant added. It also allows calculation of the composition of the isomer distribution modified with the feed and also the calculation of the expected viscosity of the plasticizer produced.

Determine the composition of the various alcohol mixtures. Knowing the structure of each single isomer may be beneficial but not essential. However, it is important that isomers can be distinguished and that their ratios can be determined from each other. When isomer compositions are generally analyzed by gas chromatography, the isomers can be distinguished by their retention index, if possible, measured in two different columns.

Examples of nonanol mixtures are given below to further illustrate the invention.

Example 1

An example of a method for analyzing a nonanol mixture is as follows:

The retention index is n-heptanol 700, n-octanol 800, n-nonanol 900, based on n-alkanols.

Since the measurement is performed in the temperature program mode of operation (see Analytical conditions), the retention index (R _i ) of the nonanol isomer is determined using the retention time (RT) between n-octanol and n-nonanol according to Calculate.

R _i = 800 + (RT _i -RT _n-octanol ): (RT _{n -nonanol} -RT _n-octanol ) ^* 100

Analysis condition

Capillary Column Length 60m

Stationary phase:

Polar Column Polyethylene Glycol 20M

Nonpolar Column 95% Polydimethylsiloxane / 5% Polydiphenylsiloxane

Carrier Gas: Helium

Flow rate: 1.5ml / min

Initial temperature: 60 ℃

Final temperature: 220 ℃

Heating rate: 2 ℃ / min

Table 1 shows the analysis of the isononanol mixture. As indicated by the analysis of some selected mixtures, it is accurate enough to take the area% equal to the weight%.

Abbreviation:

A and B = diastereomers distinguishable by gas chromatography on columns with optically inactive packaging

E = ethyl

M = methyl

DM = dimethyl

Pr = profile

X = unknown compound

Esters are prepared from various alcohol mixtures and important performance data, in particular viscosity, are measured. However, in the case of phthalate mixtures, their viscosity can be measured and the base alcohol mixture can be obtained from them and analyzed by saponification. The mixing rule is used for viscosity, but instead of the difficult nature of the ester isomers, it uses a simpler and easier to measure isomer distribution of alcohol, and the data set is non-linear regression calculation. This gives the virtual viscosity contribution of the single component to be evaluated.

This method is performed for the nonyl phthalate mixture. Tables 2a to 2f show the isomer distribution of the 52 isononanol mixtures and the viscosity of the nonyl phthalates prepared therefrom. Take diastereomers together. Unknown isomers are considered to be the actual ingredients of the formulation. Some mixtures contain 3,5,5-trimethylhexanol in addition to the components shown in Table 1.

From the data set and Equation 2 shown in Tables 2a to 2f, the program (DataFit, OAKDALE Engineering, Version 5.1, http: www.oakdaleengr.com) was used to set the viscosity hypothetical contribution for each isononolol isomer. (Table 2f, final column). This method can be used for other nonyl phthalate mixtures having other base nonanol isomers and having these and other base nonanol isomers. For the hypothetical contribution to viscosity, the accuracy of the values provided in the final column of Table 2f may increase as the number of data sets increases.

Example 2: Various Methods for Producing Diisononylphthalate (DINP) by Estering Phthalic Anhydride with a Mixture of Isomeric Nonanols

DINP to be produced has a viscosity of about 78 mPa · s and a range of 75 to 80 mPa · s. The contribution of n-nonanol to the overall viscosity is about 43 mPa · s and 3,5,5-trimethylhexanol is about 111 mPa · s.

When the DINP viscosity calculated from the isomer distribution of the prepared isononanol increases above the set range, for example, 80 mPa · s or more, n-nonanol is selected to the selected value, that is, 78 mPa · s in this example. It is added during esterification in such a manner as possible. If the calculated viscosity is less than the selected range, for example 75 mPa · s, 3,5,5-trimethylhexanol which increases the viscosity is simply added during esterification until the desired value is achieved. Similar to the mixture of alcohols in the esterification, the same effect can be achieved by mixing the esters.

In both cases, using Equation II, and since the second component used is a pure isomer, the equation is considered to be:

In the above formula,

η is the viscosity of the dialkyl phthalate mixture after two component mixing,

x _i1 is the mole fraction of isomers in alcohol mixture 1 obtained from saponification of phthalate mixture 1,

x _i2 is the mole fraction of isomers in alcohol mixture 2 obtained from saponification of phthalate mixture 2,

η _i is the viscosity parameter of the alcohol isomer,

a is the proportion of phthalate mixture 1 in the two component mixture,

(1-a) is the ratio of pure phthalate in the two component mixtures,

a / (1-a) is the mixing ratio of two components.

Using this equation, the mixture content of the two components can be calculated.

Although n-nonanol is commercially available, at commercially available 1-octene or even lower, hydroformylation of the internal n-octene can be obtained to obtain an isomeric mixture with a low contribution to viscosity, which is significantly below the selected range. 3,5,5-trimethylhexanol is also commercially available and can also be prepared by hydroformylating and hydrogenating diisobutene in a simple manner. Diisobutene is obtained through oligomerization of isobutene and is commercially available. Finally, low isomeric contributions and high isomeric mixtures are commercially available. EP 1 029 839 describes a process for obtaining isononanol having a viscosity of 77 mPa · s from an octene mixture in DINP. In addition, the octene mixture can be broken down into two fractions having a relatively low degree of branching and relatively high. After the oxo reaction, hydrogenation gives the alcohol, subsequent esterification with phthalic anhydride gives the low branched fraction giving about 68 mPa · s of DINP and the high branched fraction giving about 103 mPa · s of DINP. In the described process, it is sufficient to be commercially available for the two alcohol fractions obtained from the same raw material as the resulting isononanol.

The following examples describe the different isomeric composition DINP mixtures and the relationship between their viscosity and performance.

Example 3: Preparation of Dinonyl Phthalate Mixture (DINP)

148 g (1 mol) of phthalic anhydride, 432 g (3 mol, or 50% excess) of nonanol mixture and 0.5 g of tetra-n-butyl titanate are charged to a distillation flask equipped with a water separator and a high performance condenser and heated and boiled slowly while stirring. . The esterification is carried out at atmospheric pressure with reflux of the alcohol charge and the resulting reaction water is subsequently removed in a water separator. The esterification is continued to acid number <0.3 mg KOH / g. The alcohol is distilled off under vacuum. In neutralization, the crude ester is cooled to 80 ° C. and an appropriate amount of sodium hydroxide solution is added, followed by stirring at atmospheric pressure for about 30 minutes. The organic phase is washed repeatedly with water and the aqueous phase is removed. The ester is heated to 180 ° C. under vacuum. Distilled water (8% based on the starting weight of the crude ester) is added dropwise using a dip tube at constant temperature. Once this steam distillation is complete, a reduced pressure of 30 mbar is applied for 30 minutes at 180 ° C. to remove traces of water. The product is cooled under vacuum at 80 ° C. and filtered through a suction funnel using filter paper and filter aid.

Example 4 Measurement of Glass Transition Temperature

The dynamic viscosity of the resulting nonyl phthalate is measured according to DIN 53015 at 20 ° C. as the glass transition temperature T _g , which is a measure of the flexible action of the plasticizer, if desired. The lower the pure plasticizer T _g, T _g of the plasticized PVC produced using this in a given mixing ratio is low, Flexibility higher.

Examples of methods for measuring T _g are differential scanning calorimetry (DSC) or string torsion analysis (TBA). In the case described, the TBA method is used for higher accuracy. The method is, for example, a variant of the "conventional" torsional vibration analysis (TOA) described in DIN EN ISO 6721 part 2. In the TBA, the test material (plasticizer) is applied (18-25% by weight load) to moving desizing glass fibers in the form of a string. Stiffness G 'and loss modulus G "are measured for them at a frequency of 1s ^-1 at temperatures from -180 to + 100 ° C in a torsion-pendulum test (MYRENNE ATM III), respectively. The glass transition temperature T _g is from the maximum G". It can be measured.

Relationship between glass transition temperature and viscosity of DINP

Various nonanol mixtures are used to prepare the corresponding diisononyl phthalates and to measure the viscosity and glass transition temperature of the plasticizer (phthalate). The following table shows the relevant data.

Sample Viscosity at 20 ° C (mPas) T _g (℃) A 57.6 -84.1 B 59.5 -84.4 C 62.5 -86 D 73 -82.6 E 74.3 -81.9 F 78 -81.7 G 81 -82 H 83.9 -81.3 I 87.1 -79.5 J 89.7 -79.3 K 98 -78.3 L 110 -76.7 M 128 -73.4 N 170 -65.3

The actual linear dependence of viscosity on glass transition temperature was found. The correlation factor is 0.99 (Microsoft Excel, "Korrel" statistical function).

Example 5 Glass Transition Temperature of Plasticizer—Glass Transition Temperature Relationship of Plasticized PVC to DINP

The plasticized PVC press plaques are processed as specified below using some of the above nonanol mixtures esterified to produce phthalates.

700 g of a suspension PVC having a K value of 70 (e.g., VESTOLIT S 7054) is mixed with 300 g of plasticizer, also mixed with 2.1 g of Pebetal and 2.1 g of Barostab PB 28F, and processed to a temperature of 120 ° C. or lower to produce anhydrous blend (heat mixer). To obtain. Cool the mixture. To prepare the milled sheet, 250 g of the resulting dry blend is placed on a Schwabenthan model 1133/0578 roll mill (roll gap 1.2 mm, roll temperature 165 ° C.). As soon as the milling sheet is formed, plasticization is continued for at least 5 minutes in total. As soon as the milling sheet is removed from the roll mill and cooled, a piece (about 80 g) is cut from the milling sheet, placed on a 220 · 220 · 1 mm template, and pressed in the Werner & Pfleiderer hydraulic hand press (60t) as follows: The temperature is set at 170 ° C. and the template with milling sheet is pressed for 2 minutes at 50 bar, for 1 minute at 100 bar and finally for 2 minutes at 180 bar. The pressure is increased to 200 bar and cooling to room temperature is carried out at this temperature.

Sample Viscosity Plasticizer T _g Plasticized PVC T _g A 57.6 -84.1 -29.1 B 59.5 -84.4 -27.8 E 74.3 -81.9 -24.4 H 83.9 -81.3 -23.9 K 98 -78.3 -19.6

When the glass transition temperature of the pure plasticizer was plotted against the glass transition temperature of the plasticized PVC plaques prepared therefrom, a clear correlation was found with a coefficient of 0.98.

The correlation coefficient between the viscosity of the plasticizer and the performance variable of the glass transition temperature of the plasticized PVC plaque can be calculated as 0.98 (Microsoft Excel, "Korrel" statistical function).

Examples 3 to 5 show that plasticization of DINP, as measured by the isomeric composition of the base nonanol mixture, correlates with its viscosity.

Example 6: Relationship between glass transition temperature and viscosity of didecyl phthalate (DIDP)

Aldehyde n-valeraldehyde ("1"), 2-methylbutanal ("2") and 3-methylbutanal ("3") can be prepared by hydroformylating 1-butene, 2-butene or isobutene. Can be. Depending on whether these aldehydes (or mixtures thereof) are used as starting materials for subsequent aldol condensation and hydrogenation to obtain the corresponding C ₁₀ alcohols, various different homo- and / or coaldol condensates can be prepared. .

As described for nonanal, the C ₁₀ alcohol is reacted to yield and analyze the corresponding phthalate mixture (DIDP).

As shown below, the viscosity and glass transition temperatures are shown for some phthalic acid esters prepared from these C ₁₀ alcohols. The following compositions are measured using GC and NMR and the following abbreviations are used:

Chemical name Abbreviation 2-isopropyl-5-methyl-1-hexanol 3 + 3 2-isopropyl-4-methyl-1-hexanol (2 diastereomers) 2 + 3 2-propyl-5-methyl-1-hexanol / 2-isopropyl-1-heptanol 1 + 3 A-2-propyl-4-methyl-1-hexanol (2 diastereomers) 1 + 2 2-propyl-1-heptanol 1 + 1

Composition and physical data for various C ₁₀ phthalates based on koaldol

Sample 1 + 1 1 + 2 1 + 3 3 + 2 3 + 3 residual Viscosity (mPas) Glass transition temperature (℃) AA 98.8% 0 0 0 0 1.2% 118 -76.8 AB 14.2% 85.7% 0 0 0 0.1% 201 -69.9 AC 7.0% 0 72.3% 0 16.5% 4.2% 189 -69.5 AD 0 0 0 0 99.6% 0.4% 313 -62.7 AE 0 0 0 70.6% 29.2% 0.2% 368 -63.3 AF 29.0% 57.5% 3.0% 3.7% 5.8% 1.0% 176 -72.3

If the viscosity of C ₁₀ phthalate is plotted against the glass transition temperature (° C.), a clear correlation appears (Korrel function, correlation factor 0.95).

Example 6: Adjustment of DINP to desired values by blending, for example 70 mPa · s, 80 mPa · s, 90 mPa · s

Isononanol is mixed with n-nonanol or 3,5,5-trimethylhexanol in the ratios given in the table and reacted as described above to give the corresponding phthalates.

Sample Used alcohol Model viscosity Experimental viscosity Deviation from the model O Isononanol (INA) 76.4 75.2 1.6% P n-nonanol (n-C9) 43.8 45.8 4.5% Q 3,5,5-trimethylhexanol (TMHol) 111.9 109 2.6% R INA: n-C9 = 85: 15 70 69 1.4% S INA: n-C9 = 50: 50 58 56.9 1.9% T INA: n-C9 = 75: 25 66.5 64.3 3.3% U INA: TMHol = 80: 20 82.5 80.6 2.3% V INA: TMHol = 50: 50 92.5 89.2 3.8% W INA: TMHol = 70: 30 85.7 83.2 2.9%

If the isononanol isomer distribution used as a starting point is that the model calculates a viscosity of 76 mPa · s (sample O), and the consumer requires a specific DINP rating of about 70 mPa · s, the calculated model is about 15% n-no Nanol is determined to mix before esterification.

The viscosity predicted by the model is consistent with the values obtained experimentally (<5% deviation).

Claims (29)

A viscosity produced by esterifying a phthalic acid or phthalic anhydride with a mixture of isomeric alkyl alcohols of 4 carbon atoms, wherein the viscosity of the phthalic ester mixture is controlled through the composition of the isomeric alkyl alcohols according to formula I and the viscosity parameters thereof is 19 A mixture of isomeric dialkyl phthalates of from 44 mPa · s. Equation I In Equation I above, η is the viscosity of the dialkyl phthalate mixture, x _i is the mole fraction of isomericly pure alcohols, η _i is the viscosity parameter of the isomerically pure alcohol in the dialkyl phthalate mixture. A viscosity produced by esterifying a phthalic acid or phthalic anhydride with a mixture of isomeric alkyl alcohols of 5 carbon atoms, wherein the viscosity of the phthalic ester mixture is controlled via the composition of the isomeric alkyl alcohols according to equation (I) and viscosity parameters thereof is 24 A mixture of isomeric dialkyl phthalates of from 50 mPa · s. Equation I In Equation I above, η is the viscosity of the dialkyl phthalate mixture, x _i is the mole fraction of isomericly pure alcohols, η _i is the viscosity parameter of the isomerically pure alcohol in the dialkyl phthalate mixture. A viscosity produced by esterifying a phthalic acid or phthalic anhydride with a mixture of isomeric alkyl alcohols of 6 carbon atoms, wherein the viscosity of the phthalic ester mixture is controlled through the composition of the isomeric alkyl alcohols according to formula (I) and viscosity parameters thereof is 28 A mixture of isomeric dialkyl phthalates of from to 80 mPa · s. Equation I In Equation I above, η is the viscosity of the dialkyl phthalate mixture, x _i is the mole fraction of isomericly pure alcohols, η _i is the viscosity parameter of the isomerically pure alcohol in the dialkyl phthalate mixture. A viscosity prepared by esterifying a phthalic acid or phthalic anhydride with a mixture of isomeric alkyl alcohols of 7 carbon atoms, wherein the viscosity of the phthalic ester mixture is controlled through the composition of the isomeric alkyl alcohols according to equation (I) and viscosity parameters thereof is 33 A mixture of isomeric dialkyl phthalates of from about 100 mPa · s. Equation I In Equation I above, η is the viscosity of the dialkyl phthalate mixture, x _i is the mole fraction of isomericly pure alcohols, η _i is the viscosity parameter of the isomerically pure alcohol in the dialkyl phthalate mixture. The viscosity produced by esterifying phthalic acid or phthalic anhydride with a mixture of isomeric alkyl alcohols of 8 carbon atoms, wherein the viscosity of the phthalic ester mixture is controlled through the composition of the isomeric alkyl alcohols according to formula (I) and its viscosity parameters is 39 A mixture of isomeric dialkyl phthalates of from about 130 mPa · s. Equation I In Equation I above, η is the viscosity of the dialkyl phthalate mixture, x _i is the mole fraction of isomericly pure alcohols, η _i is the viscosity parameter of the isomerically pure alcohol in the dialkyl phthalate mixture. The viscosity prepared by esterifying phthalic acid or phthalic anhydride with a mixture of isomeric alkyl alcohols of 10 carbon atoms, wherein the viscosity of the phthalic ester mixture is controlled through the composition of the isomeric alkyl alcohols according to equation (I) and viscosity parameters thereof is 52 A mixture of isomeric dialkyl phthalates of from about 400 mPa · s. Equation I In Equation I above, η is the viscosity of the dialkyl phthalate mixture, x _i is the mole fraction of isomericly pure alcohols, η _i is the viscosity parameter of the isomerically pure alcohol in the dialkyl phthalate mixture. A viscosity prepared by esterifying phthalic acid or phthalic anhydride with a mixture of isomeric alkyl alcohols having 11 carbon atoms, wherein the viscosity of the phthalic ester mixture is controlled through the composition of the isomeric alkyl alcohols according to equation (I) and viscosity parameters thereof, is 61 A mixture of isomeric dialkyl phthalates of from about 400 mPa · s. Equation I In Equation I above, η is the viscosity of the dialkyl phthalate mixture, x _i is the mole fraction of isomericly pure alcohols, η _i is the viscosity parameter of the isomerically pure alcohol in the dialkyl phthalate mixture. Viscosities prepared by esterifying phthalic acid or phthalic anhydride with a mixture of isomeric alkyl alcohols of 12 carbon atoms, wherein the viscosity of the phthalic ester mixture is controlled via the composition of the isomeric alkyl alcohols according to equation (I) and viscosity parameters thereof, is 66 A mixture of isomeric dialkyl phthalates of from about 400 mPa · s. Equation I In Equation I above, η is the viscosity of the dialkyl phthalate mixture, x _i is the mole fraction of isomericly pure alcohols, η _i is the viscosity parameter of the isomerically pure alcohol in the dialkyl phthalate mixture. A viscosity produced by esterifying a phthalic acid or phthalic anhydride with a mixture of isomeric alkyl alcohols having 13 carbon atoms, wherein the viscosity of the phthalic ester mixture is controlled through the composition of the isomeric alkyl alcohols according to equation (I) and viscosity parameters thereof, has a viscosity of 70 A mixture of isomeric dialkyl phthalates of from about 400 mPa · s. Equation I In Equation I above, η is the viscosity of the dialkyl phthalate mixture, x _i is the mole fraction of isomericly pure alcohols, η _i is the viscosity parameter of the isomerically pure alcohol in the dialkyl phthalate mixture. The viscosity produced by esterifying phthalic acid or phthalic anhydride with a mixture of isomeric alkyl alcohols having 14 carbon atoms, wherein the viscosity of the phthalic ester mixture is controlled through the composition of the isomeric alkyl alcohols according to equation (I) and viscosity parameters thereof, is 74 A mixture of isomeric dialkyl phthalates of from about 400 mPa · s. Equation I In Equation I above, η is the viscosity of the dialkyl phthalate mixture, x _i is the mole fraction of isomericly pure alcohols, η _i is the viscosity parameter of the isomerically pure alcohol in the dialkyl phthalate mixture. Viscosities prepared by esterifying phthalic acid or phthalic anhydride with a mixture of isomeric alkyl alcohols of 9 carbon atoms, wherein the viscosity of the phthalic ester mixture is controlled through the composition of the isomeric alkyl alcohols according to equation (I) and viscosity parameters thereof, is 45 A mixture of isomeric dialkyl phthalates of from to 200 mPa · s. Equation I In Equation I above, η is the viscosity of the dialkyl phthalate mixture, x _i is the mole fraction of isomericly pure alcohols, η _i is the viscosity parameter of the isomerically pure alcohol in the dialkyl phthalate mixture. 12. The mixture of isomeric dialkyl phthalates of claim 11, wherein the mixture of isomeric alkyl alcohols having 9 carbon atoms comprises a mixture of nonanol prepared by mixing isomerically pure nonanol or nonanol mixture with n-nonanol. . The isomeric composition of claim 11, wherein the mixture of isomeric alkyl alcohols having 9 carbon atoms comprises a mixture of nonanol prepared by mixing isomerically pure nonanol or nonanol mixture with 3,5,5-trimethylhexanol. Mixtures of dialkyl phthalates. The viscosity is 19 to 44 mPa, wherein the mixture of isomeric dialkyl phthalates is prepared by mixing a mixture of isomerically pure dialkyl phthalates and / or dialkyl phthalates having 4 carbon atoms of the alkyl ester group, having a viscosity and composition according to equation IV. A mixture of isomeric dialkyl phthalates being s. Equation IV In Equation IV above, Is 1 (0 ≦ a _j ≦ 1), n is the number of components in the mixture, m is the number of alcohol isomers that are the source of the final mixture, η is the viscosity of the dialkyl phthalate mixture after component mixing, x _ij is the mole fraction of the particular isomer i in the alcohol mixture j obtained from saponification of the phthalate mixture j, η _i is the viscosity parameter of the particular alcohol isomer i, a _j is the mixture content (weight ratio) of component j (phthalate mixture) in the final product. The viscosity is 24 to 50 mPa, wherein the mixture of isomeric dialkyl phthalates is prepared by mixing a mixture of isomerically pure dialkyl phthalates and / or dialkyl phthalates with 5 carbon atoms of an alkyl ester group, having a viscosity and composition according to equation IV. A mixture of isomeric dialkyl phthalates being s. Equation IV In Equation IV above, Is 1 (0 ≦ a _j ≦ 1), n is the number of components in the mixture, m is the number of alcohol isomers that are the source of the final mixture, η is the viscosity of the dialkyl phthalate mixture after component mixing, x _ij is the mole fraction of the particular isomer i in the alcohol mixture j obtained from saponification of the phthalate mixture j, η _i is the viscosity parameter of the particular alcohol isomer i, a _j is the mixture content (weight ratio) of component j (phthalate mixture) in the final product. The viscosity is 28 to 80 mPa prepared by mixing a mixture of isomericly pure dialkyl phthalates and / or dialkyl phthalates having 6 carbon atoms of an alkyl ester group, wherein the mixture of isomeric dialkyl phthalates has a viscosity and composition according to equation IV. A mixture of isomeric dialkyl phthalates being s. Equation IV In Equation IV above, Is 1 (0 ≦ a _j ≦ 1), n is the number of components in the mixture, m is the number of alcohol isomers that are the source of the final mixture, η is the viscosity of the dialkyl phthalate mixture after component mixing, x _ij is the mole fraction of the particular isomer i in the alcohol mixture j obtained from saponification of the phthalate mixture j, η _i is the viscosity parameter of the particular alcohol isomer i, a _j is the mixture content (weight ratio) of component j (phthalate mixture) in the final product. The viscosity of the mixture of isomeric dialkyl phthalates is prepared by mixing a mixture of isomerically pure dialkyl phthalates and / or dialkyl phthalates with 7 carbon atoms of the alkyl ester group, having a viscosity and composition according to equation IV. A mixture of isomeric dialkyl phthalates being s. Equation IV In Equation IV above, Is 1 (0 ≦ a _j ≦ 1), n is the number of components in the mixture, m is the number of alcohol isomers that are the source of the final mixture, η is the viscosity of the dialkyl phthalate mixture after component mixing, x _ij is the mole fraction of the particular isomer i in the alcohol mixture j obtained from saponification of the phthalate mixture j, η _i is the viscosity parameter of the particular alcohol isomer i, a _j is the mixture content (weight ratio) of component j (phthalate mixture) in the final product. The viscosity is 39 to 130 mPa prepared by mixing a mixture of isomerically pure dialkyl phthalates and / or dialkyl phthalates having 8 carbon atoms of an alkyl ester group, wherein the mixture of isomeric dialkyl phthalates has a viscosity and composition according to equation IV. A mixture of isomeric dialkyl phthalates being s. Equation IV In Equation IV above, Is 1 (0 ≦ a _j ≦ 1), n is the number of components in the mixture, m is the number of alcohol isomers that are the source of the final mixture, η is the viscosity of the dialkyl phthalate mixture after component mixing, x _ij is the mole fraction of the particular isomer i in the alcohol mixture j obtained from saponification of the phthalate mixture j, η _i is the viscosity parameter of the particular alcohol isomer i, a _j is the mixture content (weight ratio) of component j (phthalate mixture) in the final product. The viscosity is 52-400 mPa, wherein the mixture of isomeric dialkyl phthalates is prepared by mixing a mixture of isomericly pure dialkyl phthalates and / or dialkyl phthalates having 10 carbon atoms of the alkyl ester group, having a viscosity and composition according to equation IV. A mixture of isomeric dialkyl phthalates being s. Equation IV In Equation IV above, Is 1 (0 ≦ a _j ≦ 1), n is the number of components in the mixture, m is the number of alcohol isomers that are the source of the final mixture, η is the viscosity of the dialkyl phthalate mixture after component mixing, x _ij is the mole fraction of the particular isomer i in the alcohol mixture j obtained from saponification of the phthalate mixture j, η _i is the viscosity parameter of the particular alcohol isomer i, a _j is the mixture content (weight ratio) of component j (phthalate mixture) in the final product. The viscosity is 61 to 400 mPa, wherein the mixture of isomeric dialkyl phthalates is prepared by mixing a mixture of isomerically pure dialkyl phthalates and / or dialkyl phthalates having 11 carbon atoms of the alkyl ester group, having a viscosity and composition according to equation IV. A mixture of isomeric dialkyl phthalates being s. Equation IV In Equation IV above, Is 1 (0 ≦ a _j ≦ 1), n is the number of components in the mixture, m is the number of alcohol isomers that are the source of the final mixture, η is the viscosity of the dialkyl phthalate mixture after component mixing, x _ij is the mole fraction of the particular isomer i in the alcohol mixture j obtained from saponification of the phthalate mixture j, η _i is the viscosity parameter of the particular alcohol isomer i, a _j is the mixture content (weight ratio) of component j (phthalate mixture) in the final product. The viscosity is 66-400 mPa, wherein the mixture of isomeric dialkyl phthalates is prepared by mixing a mixture of isomerically pure dialkyl phthalates and / or dialkyl phthalates having 12 carbon atoms of the alkyl ester group, having a viscosity and composition according to equation IV. A mixture of isomeric dialkyl phthalates being s. Equation IV In Equation IV above, Is 1 (0 ≦ a _j ≦ 1), n is the number of components in the mixture, m is the number of alcohol isomers that are the source of the final mixture, η is the viscosity of the dialkyl phthalate mixture after component mixing, x _ij is the mole fraction of the particular isomer i in the alcohol mixture j obtained from saponification of the phthalate mixture j, η _i is the viscosity parameter of the particular alcohol isomer i, a _j is the mixture content (weight ratio) of component j (phthalate mixture) in the final product. The viscosity is 70-400 mPa, wherein the mixture of isomeric dialkyl phthalates is prepared by mixing a mixture of isomericly pure dialkyl phthalates and / or dialkyl phthalates having 13 carbon atoms of the alkyl ester group, having a viscosity and composition according to Equation IV. A mixture of isomeric dialkyl phthalates being s. Equation IV In Equation IV above, Is 1 (0 ≦ a _j ≦ 1), n is the number of components in the mixture, m is the number of alcohol isomers that are the source of the final mixture, η is the viscosity of the dialkyl phthalate mixture after component mixing, x _ij is the mole fraction of the particular isomer i in the alcohol mixture j obtained from saponification of the phthalate mixture j, η _i is the viscosity parameter of the particular alcohol isomer i, a _j is the mixture content (weight ratio) of component j (phthalate mixture) in the final product. The viscosity is 74 to 400 mPa, wherein the mixture of isomeric dialkyl phthalates is prepared by mixing a mixture of isomerically pure dialkyl phthalates and / or dialkyl phthalates having 14 carbon atoms of the alkyl ester group, having a viscosity and composition according to Equation IV. A mixture of isomeric dialkyl phthalates being s. Equation IV In Equation IV above, Is 1 (0 ≦ a _j ≦ 1), n is the number of components in the mixture, m is the number of alcohol isomers that are the source of the final mixture, η is the viscosity of the dialkyl phthalate mixture after component mixing, x _ij is the mole fraction of the particular isomer i in the alcohol mixture j obtained from saponification of the phthalate mixture j, η _i is the viscosity parameter of the particular alcohol isomer i, a _j is the mixture content (weight ratio) of component j (phthalate mixture) in the final product. The viscosity is 45 to 200 mPa, wherein the mixture of isomeric dialkyl phthalates is prepared by mixing a mixture of isomerically pure dialkyl phthalates and / or dialkyl phthalates with 9 carbon atoms of the alkyl ester group, having a viscosity and composition according to equation IV. A mixture of isomeric dialkyl phthalates being s. Equation IV In Equation IV above, Is 1 (0 ≦ a _j ≦ 1), n is the number of components in the mixture, m is the number of alcohol isomers that are the source of the final mixture, η is the viscosity of the dialkyl phthalate mixture after component mixing, x _ij is the mole fraction of the particular isomer i in the alcohol mixture j obtained from saponification of the phthalate mixture j, η _i is the viscosity parameter of the particular alcohol isomer i, a _j is the mixture content (weight ratio) of component j (phthalate mixture) in the final product. The mixture of isomeric dialkyl phthalates of claim 24, wherein the isomerically pure dinonyl phthalate or dinonyl phthalate mixture is mixed with di (3,5,5-trimethylhexyl) phthalate. The mixture of isomeric dialkyl phthalates according to claim 24, wherein the isomerically pure dinonyl phthalate or dinonyl phthalate mixture is mixed with di (n-nonyl) phthalate. Use of a mixture of isomeric dialkyl phthalates according to any of claims 1 to 26 as a plasticizer for plastics. Use of a mixture of isomeric dialkyl phthalates according to any of claims 1 to 26 as hydraulic fluid. Use of a mixture of isomeric dialkyl phthalates according to any of claims 1 to 26 as a lubricant or a component of a lubricant.