Long-life immersion oil

Abstract

To provide an immersion oil having improved properties, especially improved properties with regard to long-term stability.SOLUTION: An immersion oil for microscopy contains a) a first diester A1 based on a tricyclodecane group K having one functional group and a first hydrocarbon derivative C1 having two functional groups, and b) a second diester A2 based on the tricyclodecane group K having one functional group and a second hydrocarbon derivative C2 having two functional groups, where C1 and C2 are different. Also provided are the use thereof and a production method thereof.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an immersion oil for microscopy comprising a) a first diester A1 based on a monofunctional tricyclodecane group K and a first bifunctional hydrocarbon derivative C1, and b) a second diester A2 based on a monofunctional tricyclodecane group K and a second bifunctional hydrocarbon derivative C2, where C1 and C2 are different, as well as to its use and to a process for its preparation. [Background technology]

[0002] Immersion oils manufactured according to DIN 8036 (June 2015) are used worldwide for microscopy. Immersion oils are essential for this application, as they allow the numerical aperture of the objectives associated with them to be increased. The numerical aperture of these objectives is frequently more specifically calculated and optimized so that they can fulfill their optical function for the use of immersion oils according to DIN 8036. Materials or mixtures suitable as immersion oils according to DIN 8036 (types N and F) have a refractive index (n e 23 1.5180(5)), dispersion value or Abbe number (ν e 43(4)), transmittance in the visible region (N-type: 400-900 nm; F-type: 320-1100 nm), residual fluorescence (F-type: 0.06 mg / L (365 nm ex. / 450 nm em.), 1.20 mg / L (405 nm ex. / 485 nm); based on quinine sulfate equivalent), and viscosity (in the range of 50-1500 mPa·s, optimally 300-1000 mPa·s). Furthermore, users of immersion oils in the field of microscopy have expectations regarding yellowness, evaporation characteristics, odor development, long-term stability, homogeneity, scattering values, and classification of health hazards associated with the components. Users generally do not know the exact numerical aperture, but it has been found in this application that values not covered by this standard are also relevant to users. These values are additionally important factors in determining whether an immersion oil is acceptable to users as a working medium.

[0003] In order to satisfy regulatory requirements and virtually all of the above user expectations, great effort must be made in the selection and combination of raw materials for immersion oils. In selecting raw materials, it must always be ensured that they have minimal yellowness, favorable evaporation characteristics, almost no odor generation, high long-term stability, and low residual fluorescence. Furthermore, no significant health risks must arise from the raw materials. Currently, partially hydrogenated polycyclic aromatics (e.g., terphenyls) and bridged condensed aliphatic hydrocarbons have been found to be particularly suitable. The effect of these two components in each case is that they exhibit a balanced ratio of refractive index and dispersion, i.e., attenuated refractive index and increased dispersion, and vice versa. Other additives that must be included in immersion oils generally serve to adjust viscosity.

[0004] Furthermore, in microscopy, apart from the influence of temperature, image quality is also affected by parameters such as the type of objective, working distance, thickness and refractive index of the cover glass, and the refractive index of the sample being examined. As modern microscopy is developed to aim for ever higher resolution, it is necessary to achieve high image quality that the immersion fluid used, e.g., immersion oil, can be adapted to the respective preparation temperature. In high-resolution microscopy, it is also necessary to deviate from the standard refractive index according to ISO 8036 and produce immersion fluids with variable refractive indexes precisely adjusted to the respective examination conditions. The reference temperature of the ISO-standard immersion fluid (ISO 8036) is 23±0.1°C, and the refractive index n e (546.1 nm) is 1.5180±0.0005. However, the requirements outlined above are not met by commercially available immersion fluids conditioned to a standard temperature of 23°C.

[0005] DE 10 2013 210 113 A1 describes an immersion fluid for microscopy that contains (a) an organic compound containing a saturated polycyclic hydrocarbon group, (b) an oligomeric or polymeric saturated acyclic hydrocarbon, and (c) an alkyl aromatic selected from the group consisting of alkylnaphthalenes and alkylbiphenyls. The document further relates to the use of the immersion fluid in microscopy and to a method for producing the immersion fluid.

[0006] DE 10 2009 010 503 B4 describes high refractive index immersion fluids, high refractive index compounds and their use in microscopes.

[0007] DE 197 05 978 B4 describes immersion oils for microscopy which contain as their main component esters or ethers of tricyclodecane or esters or ethers of substances which have the basic structure of tricyclodecane.

[0008] However, none of these documents address the long-term stability of microscopy immersion oils, which plays a key role alongside an appropriate refractive index.

[0009] It has been found that the long-term stability of immersion oil depends on the degree to which separation of the ingredients can be prevented over the period of use. In the case of components with a high tendency to crystallize, a load of crystals forms in the immersion oil, rendering it unusable. These crystals can only be remelted by prolonged heating, a very time-consuming process using equipment, for example, an oven. However, heating has a clear adverse effect on other properties of the immersion oil (e.g., residual fluorescence). Therefore, the only option left is to frequently discard the immersion oil and purchase new immersion oil. The short useful life of immersion oil (less than one year) poses production and storage problems for users, manufacturers, and suppliers, and is therefore undesirable and uneconomical.

[0010] In the region of very low residual fluorescence, the systems of condensed aliphatic hydrocarbons are particularly suitable, for example, in the case of TCD alcohol M (8(9)-hydroxymethyltricyclo[5.2.1.02,6]decane) or TCD alcohol DM (3(4),8(9)-dihydroxymethyltricyclo[5.2.1.02,6]decane), because they can be obtained with low complexity by distillation purification. However, there is a significant tendency for unfavorable crystallization, especially when using di(TCD-M) esters as the main component in immersion oils. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] DE 10 2013 210 113 A1 [Patent Document 2] DE 10 2009 010 503 B4 [Patent Document 3] DE 197 05 978 B4 Summary of the Invention [Problem to be solved by the invention]

[0012] The problem that the present invention aims to solve is therefore to provide an immersion oil with improved properties, in particular with regard to long-term stability. [Means for solving the problem]

[0013] The present invention provides a) a first diester A1 based on a monofunctional tricyclodecane group K and a bifunctional first hydrocarbon derivative C1, and b) a second diester A2 based on a monofunctional tricyclodecane group K and a second difunctional hydrocarbon derivative C2, To provide immersion oils for microscopy, C1 and C2 being different. [Effects of the Invention]

[0014] Ideally, two different diesters with similar chemical structure would prevent mutual crystallization and ensure adequate long-term stability. It is known that during crystallization, molecules orient themselves to achieve the most favorable orientation relative to other molecules. If the two partners involved have identical structures, the two substances fit precisely and can "dock" together, assuming a very close distance from each other. This process continues, resulting in crystal formation. If structurally related molecules are present in the mixture, orientation can develop. However, "docking" cannot occur. This creates a dynamic equilibrium between the two molecules, with the two molecules constantly and repeatedly withdrawing from the crystallization sites of each other. If the structural relationship between the involved molecular species is simply weak, there is no orientation of the two molecules relative to each other. What occurs then is the separate crystallization of the individual components, because there is no longer any withdrawal from the crystallization sites, despite the mixture having different chemical structure.

[0015] Immersion oils in the context of the present invention are advantageously fluids that improve the resolution of optical microscopy (UV / visible light). More particularly, immersion oils in the context of the present invention are fluids that are immersion fluids according to DIN 8036 (June 2015). [Brief explanation of the drawings]

[0016] [Figure 1] The TCD monomer is shown. [Figure 2] This refers to a TCD oligomer or polymer. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hydrocarbons in the context of the present invention are organic compounds consisting of carbon and hydrogen. In accordance with the general IUPAC definition, "aliphatic" is understood to mean non-aromatic organic compounds.

[0018] In the description of the present invention, the term "hydrocarbon derivative" can be understood to mean a hydrocarbon containing heteroatoms.

[0019] The expression "a diester based on a monofunctional tricyclodecane group K and a first / second difunctional hydrocarbon derivative C1 / C2" is based on the diester formed from the components K and C1 / C2 by functional group reaction. Ideally, this reaction proceeds via a condensation reaction. Here, a condensation reaction means that a small molecule, e.g., water, is eliminated. The expression "one functional group" is understood to mean a chemical structural unit that can react with another chemical group, e.g., by an addition reaction or a condensation reaction. The expression "two functional groups" is understood to mean a chemical structural unit that can react with two other chemical groups, e.g., by a condensation reaction. The "two functional groups" can also take the form of, for example, an acid anhydride.

[0020] Preferably, the number of carbon atoms in the first hydrocarbon derivative C1 having two functional groups differs from the number of carbon atoms in the second hydrocarbon derivative C2 having two functional groups by at least one carbon atom, very preferably by 2 to 6 carbon atoms, and most preferably by 2 carbon atoms. As a result, two different diesters having similar chemical structure patterns, optionally substituted with hydrogen atoms and suitable functional groups different from hydrogen atoms, are used, and their mutual crystallization is suppressed.

[0021] There are many possible substances having the basic structure of tricyclodecane, whose esters can be the immersion oils of the present invention. The tricyclodecane group in the description of the present invention can be understood as meaning the structural formula of the substances depicted in Figures 1a and 1b. These may be TCD monomers (Figure 1a) or TCD oligomers or polymers (Figure 1b). In Figure 1b, the ring structure enclosed in square brackets occurs n times. One or more of the hydrogen atoms in the TCD backbone may also each be substituted with a substituent R, as shown in Figure 1a. Examples of suitable substituents R are -CH2-CH2OH, -CH2OH and -OH. The substitution of hydrogen atoms by R groups preferably has only a small effect on the physical properties important for the immersion oil.

[0022] The monofunctional tricyclodecane group K preferably has 10 to 18, in particular 10 to 14 carbon atoms. More preferably, the tricyclodecane group K is a tricyclo[5.2.1.0 2.6 Tricyclodecane and its derivatives are available on an industrial scale because they can be obtained from the dimer of cyclopentadiene.

[0023] Immersion oils based on tricyclodecane are particularly suitable in the area of low residual fluorescence. The monofunctional tricyclodecane group K is therefore preferably selected from the group consisting of: JPEG0007718831000001.jpg235160

[0024] JPEG0007718831000002.jpg114160

[0025] The monofunctional tricyclodecane group K is more preferably selected from the group consisting of: JPEG0007718831000003.jpg236160

[0026] In order to favour crystallisation, the diesters A1 and A2 may be present in a particular ratio. Advantageously, the immersion oil of the invention comprises: a) a first diester A1 based on 15 to 85% by weight of a monofunctional tricyclodecane group K and a bifunctional first hydrocarbon derivative C1, and b) comprising 15 to 85% by weight of a second diester A2 based on a monofunctional tricyclodecane group K and a second difunctional hydrocarbon derivative C2.

[0027] Most preferably, the immersion oil of the present invention comprises: a) 40 to 60% by weight of a first diester A1 based on a monofunctional tricyclodecane group K and a bifunctional first hydrocarbon derivative C1, and b) containing 40-60% by weight of a second diester A2 based on a monofunctional tricyclodecane group K and a second difunctional hydrocarbon derivative C2.

[0028] Most preferably, the amounts of diesters A1 and A2 satisfy the following conditions: (i) Mass % (A1) = Mass % (A1) E ±5% by mass, (ii) Mass % (A2) = Mass % (A2) E ±5% by mass, especially (iii) Mass % (A1) + Mass % (A2) = 100 mass % [In the formula, mass% (A1) E and mass% (A2) E corresponds to the mass % of A1 and A2 at the eutectic point of the phase diagram of a mixture of A1 and A2.

[0029] Diester A1 The first diester A1 based on a monofunctional tricyclodecane group K and a bifunctional first hydrocarbon derivative C1 is preferably an ester of tricyclodecane alcohol. Preferred tricyclodecane alcohols are, in particular, hydroxymethyltricyclo[5.2.1.0 2.6 ]decane, for example 8-hydroxymethyltricyclo[5.2.1.0 2.6]decane and 9-hydroxymethyltricyclo[5.2.1.0 2.6 ]Decan.

[0030] Particularly preferred is TCD alcohol M (8-hydroxymethyltricyclo[5.2.1.0 2.6 ]decane). TCD Alcohol M is available on an industrial scale and is sold, for example, by Oxea GmbH (Oberhausen, Germany).

[0031] The first diester A1 based on a monofunctional tricyclodecane group K and a bifunctional first hydrocarbon derivative C1 is preferably an ester of a dicarboxylic acid. Examples of suitable dicarboxylic acids are phthalic acid, isophthalic acid, terephthalic acid, hexahydrophthalic acid, hexahydroisophthalic acid, hexahydroterephthalic acid, malonic acid, succinic acid, maleic acid, glutaric acid, adipic acid, or sebacic acid. Succinic acid is particularly preferred.

[0032] The esterification can be carried out using conventional esterification methods known to those skilled in the art.

[0033] The first diester A1 based on a monofunctional tricyclodecane group K and a bifunctional first hydrocarbon derivative C1 can preferably be described by the following formula (I): [ka] [In the ceremony, A 1 and A 2 are independently selected from the group consisting of -OC(O)-, -C(O)O-, -O-, methylene, and ethylene. B 1 and B 2 is C1~C 20 -Alkylene, C1-C 20 -Haloalkylene, C1-C 12 -Alkoxyalkylene, C1-C6-cyanoalkylene, C3-C 18 -Alkenylene, C3-C18 -haloalkenylene, C3- or C4-alkynylene, C3-C 12 -Cycloalkylene, C4-C 12 -Cycloalkylalkylene, -OC(O)-, -C(O)O-, C3-C 16 -alkoxycarbonylalkylene, and optionally substituted C7-C 20 -aralkylene. Y 1 is methylene, ethylene, propylene, butylene, pentylene, hexylene, and substituted or unsubstituted C8 to C 12 -alkylenearyl.

[0034] Preferably, B 1 and B 2 are independently selected from the group consisting of methylene, ethylene, n-propylene, isopropylene, n-butylene, isobutylene, sec-butylene, tert-butylene, n-pentylene, n-hexylene, n-heptylene, n-octylene, n-nonylene, n-decylene, n-undecylene, n-dodecylene, n-tridecylene, n-tetradecylene, n-pentadecylene, n-hexadecylene, n-heptadecylene, n-octadecylene, n-nonadecylene, —OC(O)—, and —C(O)O—.

[0035] Most preferably, B 1 and B 2 are independently selected from the group consisting of methylene, ethylene, n-propylene, n-butylene, —OC(O)—, and —C(O)O—.

[0036] The first diester A1 based on a monofunctional tricyclodecane group K and a bifunctional first hydrocarbon derivative C1 can preferably be described by the following formula (Ia): [ka] [In the ceremony, A 1 and A 2are independently selected from the group consisting of -OC(O)-, -C(O)O-, -O-, methylene, and ethylene. B 1 and B 2 is C1~C 20 -Alkylene, C1-C 20 -haloalkylene, -OC(O)-, -C(O)O-, and C1-C 12 -alkoxyalkylene, in particular -OC(O)- and -C(O)O-. Y 1 is selected from the group consisting of methylene, ethylene, propylene, butylene, pentylene, hexylene, and substituted or unsubstituted C8-alkylenearyl.

[0037] Very particularly preferred as diester A1 is succinic acid di(methyltricyclo[5.2.1.0 2.6 ] Deccan).

[0038] Diester A2 The second diester A2 based on a monofunctional tricyclodecane group K and a bifunctional second hydrocarbon derivative C2 is preferably an ester of tricyclodecane alcohol. Preferred tricyclodecane alcohols are, in particular, hydroxymethyltricyclo[5.2.1.0 2.6 ]decane, for example 8-hydroxymethyltricyclo[5.2.1.0 2.6 ]decane and 9-hydroxymethyltricyclo[5.2.1.0 2.6 ]Decan.

[0039] Particularly preferred is TCD alcohol M (8-hydroxymethyltricyclo[5.2.1.0 2.6 ]decane). TCD Alcohol M is available on an industrial scale and is sold, for example, by Oxea GmbH (Oberhausen, Germany).

[0040] The second diester A2 based on a monofunctional tricyclodecane group K and a difunctional second hydrocarbon derivative C2 is preferably an ester of a dicarboxylic acid. Examples of suitable dicarboxylic acids are phthalic acid, isophthalic acid, terephthalic acid, hexahydrophthalic acid, hexahydroisophthalic acid, hexahydroterephthalic acid, malonic acid, succinic acid, maleic acid, glutaric acid, adipic acid, or sebacic acid. Particularly preferred is adipic acid.

[0041] The esterification can be carried out using conventional esterification methods known to those skilled in the art.

[0042] The second diester A2 based on a monofunctional tricyclodecane group K and a bifunctional second hydrocarbon derivative C2 can preferably also be described by the following formula (II): [ka] [In the ceremony, A 1 and A 2 are independently selected from the group consisting of -OC(O)-, -C(O)O-, -O-, methylene, and ethylene. B 1 and B 2 is C1~C 20 -Alkylene, C1-C 20 -Haloalkylene, C1-C 12 -Alkoxyalkylene, C1-C6-cyanoalkylene, C3-C 18 -Alkenylene, C3-C 18 -haloalkenylene, C3- or C4-alkynylene, C3-C 12 -Cycloalkylene, C4-C 12 -Cycloalkylalkylene, -OC(O)-, -C(O)O-, C3-C 16 -alkoxycarbonylalkylene, and optionally substituted C7-C 20 -aralkylene. Y 2is methylene, ethylene, propylene, butylene, pentylene, hexylene, and substituted or unsubstituted C8 to C 12 -alkylenearyl.

[0043] Preferably, B 1 and B 2 are independently selected from the group consisting of methylene, ethylene, n-propylene, isopropylene, n-butylene, isobutylene, sec-butylene, tert-butylene, n-pentylene, n-hexylene, n-heptylene, n-octylene, n-nonylene, n-decylene, n-undecylene, n-dodecylene, n-tridecylene, n-tetradecylene, n-pentadecylene, n-hexadecylene, n-heptadecylene, n-octadecylene, n-nonadecylene, —OC(O)—, and —C(O)O—.

[0044] Most preferably, B 1 and B 2 are independently selected from the group consisting of methylene, ethylene, n-propylene, n-butylene, —OC(O)—, and —C(O)O—.

[0045] The second diester A2 based on a monofunctional tricyclodecane group K and a bifunctional second hydrocarbon derivative C2 can preferably also be described by the following formula (IIb): [ka] [In the ceremony, A 1 and A 2 are independently selected from the group consisting of -OC(O)-, -C(O)O-, -O-, methylene, and ethylene. B 1 and B 2 is C1~C 20 -Alkylene, C1-C 20 -haloalkylene, -OC(O)-, -C(O)O-, and C1-C 12 -alkoxyalkylene, in particular -OC(O)- and -C(O)O-. Y 2 is selected from the group consisting of methylene, ethylene, propylene, butylene, pentylene, hexylene, and substituted or unsubstituted C8-alkylenearyl.

[0046] Very particularly preferred as diester A2 is di(methyltricyclo[5.2.1.0]adipic acid diester 2.6 ] Deccan).

[0047] Most preferably, the immersion oil for microscopy of the present invention comprises: a) Formula (IIIa): [ka] [In the formula, Y 1 is selected from the group consisting of methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, and octylene. a first diester A1 based on a monofunctional tricyclodecane group K and a bifunctional first hydrocarbon derivative C1, b) the following formula (IIIb): [ka] [In the formula, Y 2 is selected from the group consisting of methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, and decylene. Y 1 and Y 2 are different. and a second diester A2 based on a monofunctional tricyclodecane group K and a second difunctional hydrocarbon derivative C2.

[0048] Most preferably, the immersion oil for microscopy of the present invention comprises: a) Formula (IVa): [ka] [In the formula, Y 1is selected from the group consisting of methylene, ethylene and propylene. a first diester A1 based on a monofunctional tricyclodecane group K and a bifunctional first hydrocarbon derivative C1, b) the following formula (IVb): [ka] [In the formula, Y 2 is selected from the group consisting of ethylene, propylene, butylene, pentylene, and hexylene. and a second diester A2 based on a monofunctional tricyclodecane group K and a second difunctional hydrocarbon derivative C2.

[0049] immersion oil In adjusting the parameters of refractive index, dispersion (expressed as Abbe number) and viscosity, the diesters A1 and A2 (mixture M) have the function of providing a combination of low dispersion (high Abbe number) and at the same time a relatively high refractive index. The diesters primarily serve to increase the viscosity of the immersion oil, which is particularly important at relatively high working temperatures. A very fluid immersion oil has the disadvantage that it flows out of the microscope slide too quickly and therefore is unable to maintain optical contact between the objective and the preparation for a sufficiently long time. In contrast, in the case of a very viscous immersion oil, troublesome air bubbles may form in the immersion oil when it is applied to the preparation.

[0050] The refractive index, dispersion and viscosity of the immersion oil of the present invention can be set to desired values that are particularly suited to the particular working temperature. e The Abbe number at the desired working temperature is in the range of 39 to 47. The kinematic viscosity coefficient is 150 to 1500 mm 2 The working temperature can be adjusted between 0 and 50°C, particularly 0 to 22°C and 24 to 50°C.

[0051] Preferably, in the immersion oil of the present invention, the dispersion value is in the range of 39±2 to 47±2, and most preferably in the range of 42±2 to 46±2.

[0052] An important property of immersion oil is its UV / visible transparency. Advantageously, the transmittance in the visible region of the immersion oil of the present invention is greater than 70% at wavelengths greater than 350 nm, preferably (N) greater than 90% at wavelengths greater than 400 nm and (F) greater than 90% at wavelengths greater than 365 nm, where (N) is type N immersion oil and (F) is type F immersion oil.

[0053] Particularly preferred are: a) The following formula (Va): [ka] a first diester A1 represented by b) the following formula (Vb): [ka] and a second diester A2 having the formula:

[0054] Particularly highly preferred are: a) The following formula (Va): [ka] 40 to 60% by weight of a first diester A1 represented by b) the following formula (Vb): [ka] and the sum of the amounts of A1 and A2 is 100% by weight.

[0055] In a further embodiment, the present invention provides a method for producing a pharmaceutical composition comprising: (a) reacting in a spatially unseparated one-pot reaction (i) a monofunctional tricyclodecane group K and a first bifunctional hydrocarbon derivative C1 with (ii) a monofunctional tricyclodecane group K and a second bifunctional hydrocarbon derivative C2, wherein C1 and C2 are different; (b) relates to the post-treatment of the reaction product obtained in step (a), work-up by distillation or activated carbon filtration, and preferably to the immersion oil obtainable in the formulation.

[0056] The present invention preferably comprises: (a) At the same time, (i) reacting a monofunctional tricyclodecane group K and a bifunctional first hydrocarbon derivative C1 to form a compound of formula (Ia): [ka] [In the ceremony, A 1 and A 2 are independently selected from the group consisting of -OC(O)-, -C(O)O-, -O-, methylene, and ethylene. B 1 and B 2 is C1~C 20 -Alkylene, C1-C 20 -haloalkylene, -OC(O)-, -C(O)O-, and C1-C 12 -alkoxyalkylene. Y 1 is selected from the group consisting of methylene, ethylene, propylene, butylene, pentylene, hexylene, and substituted or unsubstituted C8-alkylenearyl. to give a product represented by (ii) reacting a monofunctional tricyclodecane group K with a second bifunctional hydrocarbon derivative C2 to form a compound of formula (IIb): [ka] [In the ceremony, A 1 and A 2are independently selected from the group consisting of -OC(O)-, -C(O)O-, -O-, methylene, and ethylene. B 1 and B 2 is C1~C 20 -Alkylene, C1-C 20 -haloalkylene, -OC(O)-, -C(O)O-, and C1-C 12 -alkoxyalkylene. Y 2 is selected from the group consisting of methylene, ethylene, propylene, butylene, pentylene, hexylene, and substituted or unsubstituted C8-alkylarylene. wherein C1 and C2 are different, and (b) relates to an immersion oil that can be obtained by post-treatment and distillation purification of the reaction product obtained in step (a).

[0057] The work-up in step (b) may include termination of the reaction, an extraction step, and possible drying of the reaction product obtained.

[0058] The product obtained after distillative purification in step (b) may preferably be subjected to further purification steps, such as filtration or extraction.

[0059] Concurrent reaction is preferably understood to mean that the components to be converted react simultaneously with each other when present in the same reactor in the conversion.

[0060] The present invention more preferably comprises: (a) At the same time, (i) reacting 40 to 70 mol % of a tricyclodecane group K having one functional group and 10 to 30 mol % of a first hydrocarbon derivative C1 having two functional groups to obtain a compound of the following formula (Ia): [ka] [In the ceremony, A 1 and A 2are independently selected from the group consisting of -OC(O)-, -C(O)O-, -O-, methylene, and ethylene. B 1 and B 2 is C1~C 20 -Alkylene, C1-C 20 -haloalkylene, -OC(O)-, -C(O)O-, and C1-C 12 -alkoxyalkylene. Y 1 is selected from the group consisting of methylene, ethylene, propylene, butylene, pentylene, hexylene, and substituted or unsubstituted C8-alkylenearyl. to give a product represented by (ii) reacting 40 to 70 mol % of a monofunctional tricyclodecane group K and 5 to 25 mol % of a bifunctional second hydrocarbon derivative C2 to give a compound of the following formula (IIb): [ka] [In the ceremony, A 1 and A 2 are independently selected from the group consisting of -OC(O)-, -C(O)O-, -O-, methylene, and ethylene. B 1 and B 2 is C1~C 20 -Alkylene, C1-C 20 -haloalkylene, -OC(O)-, -C(O)O-, and C1-C 12 -alkoxyalkylene. Y 2 is selected from the group consisting of methylene, ethylene, propylene, butylene, pentylene, hexylene, and substituted or unsubstituted C8-alkylenearyl. wherein C1 and C2 are different, and (b) relates to an immersion oil obtainable by distillation purification of the reaction product obtained in step (a).

[0061] The product obtained after distillative purification in step (b) may preferably be subjected to further purification steps, such as filtration or extraction.

[0062] The present invention further relates to the use of the immersion oil of the present invention in microscopy, in particular for light and fluorescence microscopy.

[0063] The present invention more preferably comprises: (a) At the same time, (i) reacting a monofunctional tricyclodecane group K and a bifunctional first hydrocarbon derivative C1 to form a compound of formula (Ia): [ka] [In the ceremony, A 1 and A 2 are independently selected from the group consisting of -OC(O)-, -C(O)O-, -O-, methylene, and ethylene. B 1 and B 2 is C1~C 20 -Alkylene, C1-C 20 -haloalkylene, -OC(O)-, -C(O)O-, and C1-C 12 -alkoxyalkylene. Y 1 is selected from the group consisting of methylene, ethylene, propylene, butylene, pentylene, hexylene, and substituted or unsubstituted C8-alkylenearyl. to give a product represented by (ii) reacting a monofunctional tricyclodecane group K with a second bifunctional hydrocarbon derivative C2 to form a compound of formula (IIb): [ka] [In the ceremony, A 1 and A 2 are independently selected from the group consisting of -OC(O)-, -C(O)O-, -O-, methylene, and ethylene. B 1 and B2 is C1~C 20 -Alkylene, C1-C 20 -haloalkylene, -OC(O)-, -C(O)O-, and C1-C 12 -alkoxyalkylene. Y 2 is selected from the group consisting of methylene, ethylene, propylene, butylene, pentylene, hexylene, and substituted or unsubstituted C8-alkylenearyl. wherein C1 and C2 are different, and (b) Use of the immersion oil obtainable by distillation purification of the reaction product obtained in step (a) for microscopic examination.

[0064] The present invention further comprises: i) providing a first diester A1 and a second diester A2 as a mixture M, ii) optionally providing further ingredients, and iii) A method for producing an immersion oil, comprising the step of mixing the first diester A1 and the second diester A2 with further ingredients.

[0065] In the production method of the present invention, step i) is preferably carried out by providing a mixture M consisting of a first diester A1 and a second diester A2, and providing the mixture M comprises: iv) providing a solution of a first bifunctional hydrocarbon derivative C1 and a second bifunctional hydrocarbon derivative C2 in a solvent; v) adding a monofunctional tricyclodecane group K, and vi) optionally heating the reaction mixture and optionally adding an esterification catalyst.

[0066] In the production method of the present invention, preferably, step vi) is followed by vii) transferring the obtained crude product, and viii) Optionally, a step of purifying the crude product obtained is carried out.

[0067] The preparation of a mixture of two di(TCD-M) esters (A1 and A2) is particularly advantageous, cost-effective, and time-saving when they are synthesized directly in one step from dicarboxylic acids (C1 and C2) and a TCD alcohol M (K). First, dicarboxylic acids (e.g., adipic acid and succinic acid) are added to a reaction vessel in the optimal eutectic ratio with the TCD alcohol M and a solvent, followed by a conventional esterification reaction with PTSA (paratoluenesulfonic acid). The advantage of this reaction scheme is that no crystalline product is formed, allowing for further processing and distillative purification of the reaction mixture via pumped circulation. A further advantage is the simultaneous synthesis of the diesters, which have high long-term stability after preparation. [Example]

[0068] Preparation of mixed esters of TCD alcohol M Examples 1 to 4 : A solution of carboxylic acid 1 and carboxylic acid 2 in cyclohexane was prepared, and TCD alcohol M was added. Heating was performed, and paratoluenesulfonic acid (PTSA) was added. The types and amounts of carboxylic acids used are shown in Table 1. Water is produced by the reaction, and this water is used to monitor the progress of the reaction. After the reaction is complete, the reaction mixture is cooled, and the solution is repeatedly washed with water or a salt solution (e.g., sodium chloride solution). A crude fraction is released from cyclohexane. The product is either used directly or first purified by distillation and / or activated carbon filtration.

[0069] [Table 1]

[0070] Table 2 shows the physical properties important for immersion oils for some preferred di(TCD methylol) esters. The essential factor for the excellent suitability of aliphatic di(TCD methylol) esters as the main component of immersion oils is the refractive index n e >1.5, and at the same time a high Abbe number ν e≥46 (ν of di(TCD methylol) maleate) e =47), and the Abbe number ν of other di(TCD methylol) esters further specified e >50. The good UV transparency of di(TCD methylol) ester is also important, with less than 10% transmission only at wavelengths below 320 nm at a layer thickness d of 10 mm.

[0071] [Table 2]

[0072] Refractive index and Abbe number : The refractive index was measured using a thermostat, a mercury-cadmium spectrometer lamp, and a 480.0 nm (n F’ ), 546.1nm(n e ) and 643.8 nm (n C’ The viscosity coefficients shown in the table were measured using a Zeiss Abbe refractometer equipped with an interference filter. 20 This can be converted into the kinematic viscosity coefficient by dividing by

[0073] Calculating the Abbe number :

number

[0074] The kinematic viscosity coefficients were determined in an Ubbelohde viscometer in accordance with DIN 51562-1 (January 1997) using a Lauda PVS 1 automatic capillary viscometer. Viscosity coefficients and kinematic viscosity coefficients can be interconverted using specific gravity according to known methods.

Claims

1. a) a first diester A1 based on 15 to 85% by weight of a monofunctional tricyclodecane group K and a bifunctional first hydrocarbon derivative C1, and b) comprising 15 to 85% by weight of a second diester A2 based on monofunctional tricyclodecane radicals K and a second difunctional hydrocarbon derivative C2, 1. An immersion oil for microscopy, wherein C1 and C2 are different, The monofunctional tricyclodecane group K is selected from the group consisting of: An immersion oil, wherein a first diester A1 is represented by the following formula (I) and a second diester A2 is represented by the following formula (II): wherein A 1 and A 2 are independently selected from the group consisting of —O—C(O)—, —C(O)O—, —O—, methylene and ethylene. B 1 and B 2 are independently selected from the group consisting of C 1 -C 20 -alkylene, C 1 -C 20 -haloalkylene, C 1 -C 12 -alkoxyalkylene, C 1 -C 6 -cyanoalkylene, C 3 -C 18 -alkenylene, C 3 -C 18 -haloalkenylene, C 3 - or C 4 -alkynylene, C 3 -C 12 -cycloalkylene, C 4 -C 12 -cycloalkylalkylene, -O-C(O)-, -C(O)O-, C 3 -C 16 -alkoxycarbonylalkylene, and optionally substituted C 7 -C 20 -aralkylene. Y 1 is selected from the group consisting of methylene, ethylene, propylene, butylene, pentylene, hexylene, and substituted or unsubstituted C 8 -C 12 -alkylenearyl. Y 2 is selected from the group consisting of methylene, ethylene, propylene, butylene, pentylene, hexylene, and substituted or unsubstituted C 8 -C 12 alkylenearyl.

2. 2. The immersion oil according to claim 1, wherein the number of carbon atoms in the first hydrocarbon derivative C1 having two functional groups and the number of carbon atoms in the second hydrocarbon derivative C2 having two functional groups differ by at least one carbon atom.

3. 3. Immersion oil according to claim 1, wherein the monofunctional tricyclodecane group K is selected from the group consisting of:

4. The amounts of diesters A1 and A2 are as follows: (i) Mass % (A1) = Mass % (A1) E ±5% by mass, (ii) Mass % (A2) = Mass % (A2) E ±5 mass% [In the formula, mass% (A1) E and mass% (A2) E corresponds to the mass % of A1 and A2 at the eutectic point of the phase diagram of a mixture of A1 and A2.] 4. The immersion oil according to claim 1, wherein the immersion oil satisfies the following:

5. 5. The immersion oil according to claim 1, wherein the dispersion value is within the range of 39±2 to 47±2.

6. 6. An immersion oil according to claim 1, wherein the transmittance in the visible region is greater than 70% at wavelengths greater than 350 nm.

7. (a) a one-pot reaction that is not spatially separated, (i) a monofunctional tricyclodecane group K and a bifunctional first hydrocarbon derivative C1 (ii) reacting a monofunctional tricyclodecane group K with a second bifunctional hydrocarbon derivative C2, where C1 and C2 are different; and (b) Post-treatment of the reaction product obtained in step (a), work-up by distillation or activated carbon filtration 7. The immersion oil according to claim 1, wherein the immersion oil is obtained by

8. Use of an immersion oil according to any one of claims 1 to 7 in microscopy.

9. i) providing a first diester A1 and a second diester A2 as a mixture M, ii) optionally providing further ingredients; and 9. A method for producing an immersion oil according to any one of claims 1 to 8, comprising the step of: iii) mixing the first diester A1 and the second diester A2 with further ingredients.

10. 10. The method according to claim 9, wherein step i) is carried out by providing a mixture M consisting of a first diester A1 and a second diester A2, Providing a mixture M iv) providing a solution of a first bifunctional hydrocarbon derivative C1 and a second bifunctional hydrocarbon derivative C2 in a solvent; v) adding a monofunctional tricyclodecane group K, and vi) optionally heating the reaction mixture and optionally adding an esterification catalyst.

11. Following step vi), vii) transferring the obtained crude product; and 11. The method according to claim 10, further comprising the optional step of purifying the crude product obtained.

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