JPH03233355A - Filler for liquid chromatography - Google Patents

Abstract

PURPOSE:To separate even a compd. which is hardly separated in an alkyl group bonding-type stationary phase by using a filler obtained by allowing a specified cyclic polysiloxane to react with a porous carrier. CONSTITUTION:A cyclic polysiloxane shown by the formula (where R<1>-R<4> are a monovalent hydrocarbonic group, X is a halogen atom or a hydrolyzable org. group, l is an integer of 1-10, m is an integer of 0-10, l+m is an integer of >= 3, n is an integer of 1-20, and p is an integer of 0-2) is allowed to react with a porous carrier having an active hydrophilic group on its surface to obtain a filler which is used. A globular or crushed porous silica gel or alumina or a porous glass having an active hydrophilic group on its surface are preferably used as the porous carrier having an active hydrophilic group on its surface. As for the cyclic polysiloxane, the R<1>-R<4> are a monovaelent hydrocarbonic group exemplified by a methyl group, and a halogen atom such as chlorine or an alkoxy group is preferably used as the X.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a packing material for liquid chromatography. Specifically, the present invention relates to a packing material for liquid chromatography that has excellent separation properties.

[Prior Art] A packing material obtained by chemically bonding an alkyl group having 1 to 18 carbon atoms to a porous carrier such as silica gel is widely used as a packing material for liquid chromatography, and is used for analysis of most organic compounds. Effective for preparative separation, etc. However, these alkyl group-bonded stationary phases have problems such as difficulty in separating certain compounds, such as compounds with similar solubility in alkyl groups such as anthracene and Cf5-stilbene. Ta.

[Problems to be Solved by the Invention] The present inventors have conducted intensive research to solve the above problems, and as a result, a porous carrier is reacted with a specific cyclic polysiloxane, which is used as a packing material for liquid chromatography. The inventors have discovered that this makes it possible to separate compounds that are difficult to separate using the alkyl group-bonded stationary phase as described above, leading to the present invention.

[Means for Solving the Problems] The present invention provides the following advantages: ``(A) a porous carrier having an active hydrophilic group on its surface, (B) a general formula, (CH2) n S I R', Xl-p (formula During,
RI, R2, R1, R4 are monovalent hydrocarbon groups, X is a halogen atom or a hydrolyzable organic group, and 9 is 1
m is an integer of 0 to 10, 90 m is an integer of 3 or more, n is an integer of 1 to 20, and P is an integer of 0 to 2.

A packing material for liquid chromatography made by reacting a cyclic polysiloxane represented by ). ” related.

The porous carrier having an active hydrophilic group on the surface of the component (A) used in the present invention includes spherical or crushed porous silica gel or alumina, and porous glass having an active hydrophilic group on the surface. desirable. The size of these carrier particles is 1-100 microns, preferably 3-30 microns, and their surface area is 100-500//g, preferably 200-400//g.

In the cyclic polysiloxane component (B) used in the present invention, in the above formula, RIIR"lR" is a methyl group.

A monovalent hydrocarbon group exemplified by an ethyl group, a propyl group, etc.; 7-siloxy groups such as trifluoroacetoxy groups; alkylamino groups such as methylamino groups and ethylamino groups; oxime groups such as methylethylketoxime groups; hydrolyzable organic groups such as isopropenyloxy groups; Among these, a halogen atom or an alkoxy group is preferred. 9 is 1~
The integer 1m of 10 is an integer of 0 to 10 +Q+m is an integer of 3 or more. n is an integer of 1 to 20, and P is an integer of 0 to 2.

Examples of such cyclic polysiloxane include 2,
4. [i, 8-tetramethyl-2,4,6,8-tetrakis(2-dimethylchlorosilylethyl)cyclotetrasiloxane, 2,4,8.8-tetramethyl-2,
4,G,8-tetrakis(4-dimethylchlorosilylbutyl)cyclotetrasiloxane, 2,4.6.8-
Tetramethyl-2,4,Ili, 8-tetrakis (6-
(dimethylchlorosilylhexyl)cyclotetrasiloxane, 2.4,8゜8-tetramethyl-2,4,G,
8-tetrakis(8-dimethylchlorosilyloctyl)
Chlorosilanes such as cyclotetrasiloxane, 2,4,8.8-tetramethyl-2,4,6,8-tetrakis(1G-/methylchlorosilyldecyl)cyclotetrasiloxane; 2,4,6°8-tetra Methyl-2,
Dichlorosilanes such as 4,8,8-tetrakis(2-methyldichlorosilylethyl)cyclotetrasiloxane; 2,4. B, 8-tetramethyl-2,4,6,8-
Trichlorosilanes such as tetrakis(2-trichlorosilylethyl)cyclotetrasiloxane; 2,4,8
．． 8-tetramethyl-2,4,8,8-tetrakis(2
-dimethylmethoxysilylethyl) cyclotetrasiloxane; acyloxysilanes in which an acetoxy group is bonded instead of the methoxy group of the silyltetrasiloxane; 2,2,4,4. G, copolymerized cyclosiloxane such as 8-hexamethyl-8,8-bis(2-dimethylchlorosilylethyl)cyclotetrasiloxane.

2.4. Ei, 8.10-pentakis(2-dimethylchlorosilylethyl).

The packing material for liquid chromatography of the present invention is obtained by reacting component (A) with component (B) as described above. The active hydroxyl groups of component (A) and (B
) The method of condensation reaction with the hydrolyzable organic group of the component is - in the membrane. The required amount of component (B) in this reaction is equivalent to or less than the active hydroxyl group on the surface of the porous carrier of component (A), but it is sufficient to react with 2 to 3 times the equivalent amount to the active hydroxyl group on the surface of the porous carrier. Alternatively, a composite layer of cyclic polysiloxane may be formed.

The desired amount to be treated with component (B) varies depending on the physical properties of the porous carrier, the type of cyclic polysiloxane, the type of compound to be separated, etc., but the appropriate amount is within the range of 5 to 20% based on the carbon analysis value. be.

It is generally advantageous to carry out this reaction in the presence of an organic solvent, but the organic solvent used here must dissolve the cyclic polysiloxane well and be inert towards the cyclic polysiloxane. is necessary. Such organic solvents include n-hexane, n-hebutane, n-octane+
Saturated hydrocarbons such as n-decane, isooctane, cyclohexane; halogenated hydrocarbons such as chloroform, carbon tetrachloride, dichloroethane, trichloroethane, tetrachloroethane, dichloropropane; aromatic hydrocarbons and chlorobenzene such as henzene, toluene, xylene, ethylbenzene , dichlorobenzene, trichlorobenzene and other aromatic halides.

The temperature and reaction time of this reaction are usually selected between room temperature and the boiling point of the organic solvent, and generally between 50°C and 10°C.
The duration is from several hours to 20 hours at a temperature range of 0°C.

In the liquid chromatography packing material of the present invention thus obtained, a small amount of unreacted silanol groups may remain on the surface of the porous carrier depending on the reaction conditions. Although it is possible to use such silanol groups,
It is known that such silanol groups cause irreversible adsorption during chromatography of cationic substances to be eluted.

Therefore, if the remaining silanol groups are inconvenient, it is preferable to perform a surface treatment generally called "capping" to eliminate the remaining silanol groups. In the present invention, in order to eliminate the remaining silanol groups, it is preferable to treat the surface of the liquid chromatography packing material obtained as described above with an organosilicon compound called a silylating agent. Here, as the silylating agent, for example, general formula S i R'R
'R'Z (wherein R8IR", R" is an alkyl group,
It represents a monovalent hydrocarbon group exemplified by an alkylaryl group, and R6, RIt, and RT may all be the same or different. 2 is a halogen atom, carbon number 1~
4 alkoxy group.

C1-4 dialkylamino group and C1-4
Examples of these silylating agents include trimethylchlorosilane, trimethylbromosilane, ethyldimethylchlorosilane, trimethylmethoxysilane, trimethylethoxysilane, trimethylsilylacetamide,
Examples include bis(trimethylsilyl)acetamide. The same method as that for reacting the porous carrier with the cyclic polysiloxane described above can be applied to the reaction for eliminating the silanol groups.

For example, when using a lower alkylsilane compound as a silylating agent, it is used in an amount equal to or more than the remaining silanol group, and a heating reaction is carried out at a temperature of 50°C to 100°C for about 1 to 20 hours. It can be completed.

As conditions for using the packing material for liquid chromatography of the present invention, well-known conditions for ordinary reversed phase chromatography can be applied. That is, the packing material for liquid chromatography of the present invention can be packed into a suitable column for chromatography, and separation can be carried out according to a conventional method using an aqueous solution of a suitable organic solvent as a developing solvent. Here, as the organic solvent, a wide range of water-soluble and inert organic solvents can be used, but usually lower alcohols such as methanol, ethanol, n-propanol, l5O-propanol, acetonitrile, and tetrahydrofuran are used. etc. are used.

In liquid chromatography, when evaluating and considering whether two peaks are separated, the degree of separation (Rs) is used as a measure, and this is expressed by the following formula.

Rs = 2 (TA-TB) / (WA+WB) where TA is the elution time of peak A (seconds) TB is the elution time of peak B (seconds) WA is the peak width above the baseline of peak A (seconds) WB is Peak Width on the Baseline of Peak B (Seconds) Regarding the degree of separation, the larger the value, the better the separation of the peaks and the more suitable it is for separating the substance to be separated used. The liquid chromatography packing material of the present invention as described above exhibits a high degree of separation for various compounds such as aromatic compounds, which were difficult to separate using conventional liquid chromatography packing materials. It can be used for analysis and separation and purification.

[Example] The present invention will be explained below with reference to Examples.

Reference Example 1 2.4.8.Synthesis of 8-tetramethyl-2,4,[i,8-tetrakis(6-dimethylchlorosilylhexyl)cyclotetrasiloxane 1,5-hexadiene 24+, 1 g (2.93 moles) and 0.12 g of a 3% isopropyl alcohol solution of chloroplatinic acid were added and heated to 50°C. Next, 291.4 g (3
, 08 mol) was gradually added dropwise. At that time, since heat was generated, the reaction was carried out while appropriately cooling the flask. After the dropwise addition was completed, heating was continued at 60°C to 70°C for 2 hours. The reaction product was then collected at 110 °C/80 sm using a Widmer distillation tube. When the obtained reaction product was analyzed by gas chromatography, it was confirmed to be 5-hexenyldimethylchlorosilane. Moreover, the yield was 251.7 g, the purity was 97.5%, and the yield was 48.6%.

Next, 251.7 g of 5-hexenyldimethylchlorosilane obtained above was placed in 1000 ad 14 flasks.
(1,425 mol), 3% isopropyl alcohol solution of chloroplatinic acid 0. 3g of f was added and heated to 80°C. Next, 2. 4. 85.7 g (0,358 mol) of 8°8-tetramethylcyclotetrasiloxane was gradually added dropwise. At that time, since heat was generated, the reaction was carried out while appropriately cooling the flask. When the obtained reaction product was analyzed by gas chromatography, nuclear magnetic resonance analysis, and infrared absorption spectroscopy, it was found that 2. 8. It was confirmed that it was 8-tetramethyl-2,4,6°8-tetrakis(6-dimethylchlorosilylhexyl)cyclotetrasiloxane. Moreover, the yield was 327.3 g, and the yield was 97%.

Example 1 In a 30011 four-loaf flask equipped with a reflux condenser, a stirrer, a thermometer and a liquid dropper, 200 l of dry toluene and dry pyridine were added.

5- was added. Next, silica gel 5 with an average pore diameter of 120 angstroms, a specific surface area of 200 g, and an average particle size of 5 microns was obtained by drying at 150° C. for 18 hours under reduced pressure.
I added g. While stirring, 5.0 g of cyclotetrasiloxane obtained in Reference Example 1 was gradually added thereto, and the mixture was reacted at reflux temperature for 3 hours. Next, add 2.0 d of pure water,
It was heated at reflux temperature for an additional 2 hours. After the reaction was completed, the reaction product was filtered through a glass filter. Next, in order to remove unreacted cyclotetrasiloxane and pyridine salts, it was dissolved in 100- to 200- toluene, methanol, 50% methanol aqueous solution, water, and acetone, respectively. Next, this was dispersed in an ultrasonic bath for about 3 minutes, filtered and washed, and then dried under reduced pressure at 80° C. for 18 hours to obtain a cyclotetrasiloxane-treated silica gel.

Next, four pieces of this silica gel were transferred to a Lough flask, and additionally 200° of dry toluene and 3° of pyridine were added. 8.5 g of trimethylchlorosilane was added dropwise while stirring, and the mixture was heated at reflux temperature for 3 hours. Thereafter, the reaction product was filtered through a glass filter. Next, each of these is 1
00 to 200- dissolved in toluene, methanol, 50% methanol aqueous solution, water and acetone, dispersed in an ultrasonic bath for about 3 minutes, filtered and washed, and then heated at 80°C under reduced pressure for 18
A silica gel treated with cyclotetrapolysiloxane was obtained by drying for hours to eliminate residual silanol. The elemental analysis values of this silica gel were 8.3% carbon and 8.1% hydrogen.

Next, this cyclotetrasiloxane-treated silica gel was used as a packing material for liquid chromatography to analyze benzene-naphthalene and biphenyl.

A mixture of aromatics consisting of anthracene and Cl5-stilbene was separated. Here, this silica gel is
A stainless steel column with an inner diameter of 6.0 m and a length of 15 cm was packed. An ultraviolet absorption spectrophotometer was used as a detector. In addition, a 70% aqueous methanol solution was used as the organic solvent for developing the mixture of aromatic compounds. The obtained chromatogram is shown in FIG. In addition, the degree of separation calculated from the peaks of anthracene and Cl5-stilbene is 3.
．． It was 34.

Example 2 In place of the cyclotetrasiloxane used in Example 1, 2. 4. 6. 8-tetramethyl-2,4,
A cyclotetrasiloxane-treated silica gel was obtained in the same manner as in Example 1 except that 8,8-tetrakis(6-dimethylchlorosilylethyl)cyclotetrasiloxane was used. The elemental analysis value of the obtained silica gel is carbon E3.1%
, hydrogen was 1.4%. Further, the properties of this silica gel as a packing material for liquid chromatography were measured in the same manner as in Example 1, and the degree of separation calculated from the peaks of anthracene and Cl5-stilbene was 5.07.

Example 3 1.1', 2.2', 3.3', 4.4'-tetra(dimethylmethoxysilylhexyl)tetramethylcyclotetrasiloxane was used in place of the cyclotetrasiloxane used in Example 1. A cyclotetrasiloxane-treated silica gel was obtained in the same manner as in Example 1 except that 0 g was used. The elemental analysis value of the obtained silica gel was 5.9% carbon;
The hydrogen content was 1.3%. The separation power of this silica gel in liquid chromatography was measured in the same manner as in Example 1, and the degree of separation calculated from the peaks of anthracene and Cl5-stilbene was 3. It was OO.

Example 4 Cyclotetracylo + + 7 used in Example 1
(D range b linear 1.1'+2.2', 3.3', 4.
A cyclotetrasiloxane-treated silica gel was obtained in the same manner as in Example 1, except that 5.0 g of 4'-te)-7(methyldichlorosilyldecyl)tetramethylcyclotetrasiloxane was used. The elemental analysis values of the obtained silica gel were 12.1% carbon and 267% hydrogen. Furthermore, the characteristics of this silica gel as a packing material for liquid chromatography were measured in the same manner as in Example 1, and the degree of separation calculated from the peaks of anthracene and Cl5-stilbene was 7.
．． It was 30.

Example 5 Same as Example 1 except that 5.0 g of 1.1',2,2'-bis(dimethylchlorosilylhexyl)bismethylbisdimethylcyclotetrasiloxane was used in place of the cyclotetrasiloxane used in Example 1. A cyclotetrasiloxane-treated silica gel was obtained in the same manner. The elemental analysis values of the obtained silica gel were 6.2% carbon and 1.1% hydrogen. Further, the characteristics of this silica gel as a packing material for liquid chromatography were measured in the same manner as in Example 1, and the degree of separation calculated from the peaks of anthracene and Cl5-stilbene was 2.48.

Comparative Example 1 A chlorosilane-treated silica gel was obtained in the same manner as in Example 1, except that 6.5 g of n-octadecyldimethylchlorosilane was used instead of the cyclotetrasiloxane used in Example 1. The elemental analysis values of the obtained silica gel were 8.4% carbon and 1.7% hydrogen.

Thereafter, in the same manner as in Example 1, this chlorosilane-treated silica gel was used as a packing material for liquid chromatography to separate a mixture of aromatic compounds consisting of benzene, naphthalene, biphenyl, anthracene, and Cl5-stilbene.

The obtained chromatogram is shown in FIG.

Further, the degree of separation calculated from the peaks of anthracene and Cl5-stilbene was 0.67.

[Effects of the Invention] The liquid chromatography packing material of the present invention is made by reacting component (A), a porous carrier having a hydrophilic group on the surface, with component (B), a specific cyclic polysiloxane.
Figure 1 shows that it is possible to separate various compounds such as aromatic compounds that are difficult to separate using conventional packing materials for liquid chromatography, and the degree of separation is very high. Chromatograms of various aromatic compounds separated are shown.

FIG. 2 shows chromatograms of various aromatic compounds separated in Comparative Example 1.

1: Benzene, 2: Naphthalene, 3: Biphenyl, 4: Anthracene, 5: Cl5
-Stilbene

Claims (1)

[Scope of Claims] 1 (A) A porous carrier having active hydrophilic groups on the surface (B
) General formula, ▲Mathematical formula, chemical formula, table, etc.▼ (In the formula, R^1, R^2, R^3, R^4 are monovalent hydrocarbon groups, and X is a halogen atom or a hydrolyzable organic group, g is an integer of 1 to 10, m is an integer of 0 to 10, l+
m is an integer of 3 or more, n is an integer of 1 to 20, and P is an integer of 0 to 2. A packing material for liquid chromatography made by reacting a cyclic polysiloxane represented by ). 2. The packing material for liquid chromatography according to claim 1, wherein X is an alkoxy group having 1 to 4 carbon atoms.