JPS5929662A - 4-(2,4-dihydroxyphenyl)piperidine compound and its preparation - Google Patents

Abstract

NEW MATERIAL:The 4-(2,4-dihydroxyphenyl)piperidine compound of formula I (R<1>-R<5> are H or lower alkyl). EXAMPLE:2,2,6,6-Tetramethyl-4-(2,4-dihydroxyphenyl)piperidine. USE:Weather stabilizer and heat deterioration preventive for synthetic resins. It is effective to synthetic resins such as polyolefin (e.g. polyethylene, polypropylene, etc.), polystyrene, polyvinyl chloride, polyester, polyamide, polyurethane, etc., especially polyolefin. PROCESS:The compound of formula I is prepared by hydrogenating the 4-(2,4- dihydroxyphenyl)-3,4-dehydropiperidine compound of formula II with H<2> in a solvent preferably methanol, etc., in liquid phase, in the presence of a hydrogenation reduction catalyst such as Pd/C, Raney Ni, etc. at 15-60 deg.C under normal or positive pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to 4-(2,4-dihydroxyphenyl)piperidines, which are novel compounds that are excellent as weathering stabilizers and thermal deterioration inhibitors for resins, and methods for producing the same.

Conventionally, various compounds have been proposed that are effective as weathering stabilizers and thermal deterioration inhibitors for resins.

The inventors have discovered that 4-(2,4-dihydroxyphenyl)
4-(2,4-dihydroxyfuuninolipiperidines obtained by hydrogenating -6,4-dehydropiperidines) is a new compound, and this compound is excellent as a weathering stabilizer and thermal deterioration inhibitor for resins. The present invention was achieved based on the discovery that

To summarize the present invention, the present invention is based on the general formula [I]4 [wherein R1, R2, R3, R4 and R each represent a hydrogen atom or a lower alkyl group]. ] 4
-(2,4-dihydroxyphenyl)piperidines,
It is defined as a material invention, and furthermore, general formula (1) [wherein, R1, R2
, R3, R4 and R5 each represent a hydrogen atom or a lower alkyl group. General formula (1)) characterized by reacting 4-(2,4-dihydroxyphenyl)-3,4-dehydropiperidines represented by [Formula (1)] with hydrogen in the presence of a hydrogenation reduction catalyst. Among them, R1, R2, R3, R4 and R5 are the same as above. ] A method for producing 4-(2,4-dihydroxyphenyl)piperidines represented by the following is defined as a production method invention.

The 4-(2,4-dihydroxyphenyl)piperidines of the present invention are represented by the general formula (1) [wherein R1, R2, R3, R4 and R each represent a hydrogen atom or a lower alkyl group]. ] is a compound represented by R in the general formula (1), R%R3,
Specifically, R4 and R5 are a hydrogen atom; a lower alkyl group such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a 5ee-butyl group, and a tart-butyl group. Specifically, the 4-(2,4-dihydroxyphenyl)piperidines of the present invention include 4-(2,4-dihydroxyphenyl)piperidine,
2.6-dimethyl-4-(2,4-dihydroxyphenyl)piperidine, 2+6'' ethyl-4-(2,4-1 hydroxyphenyl)piperidine, 2.2.6.6-titramethyl-4-(2,4 -dihydroxyphenyl)piperidine, 2.2,6.6-titraethyl-4-(2,4-dihydroxyphenyl)piperidine, 2.2,6.6-titrabroby-4-(2,4-dihydroxyphenyl)piperidine, 4- In addition, these 4- (
N-lower alkylated products of 2,4-dihydroxyphenyl)piperidines can also be exemplified. Among these 4-(2,4-dihydroxyphenyl)piperidines, R1, R2,
Compounds in which R3 and R4 are both lower alkyl groups are preferred because they have excellent performance as weather stabilizers and thermal deterioration inhibitors for resins.

4-(2,4-dihydroxyphenyl)-3,4-dehydropiperidines, which are raw materials for producing 4-(2,4-dihydroxyphenyl)piperidines of the present invention, have the general formula (1
) [In the formula, R, R, R, R and R each represent a hydrogen atom or a lower alkyl group. ] is a compound represented by In the general formula (ID), specific examples of R1, R2, R3, R4 and R5 include a hydrogen atom and a lower alkyl group as described above.
(2,4-dihydroxyphenyl)-6,4-dehydropiperidines include 4-(2,4-dihydroxyphenyl)-3,4-dehydropiperidine, 2,6-cymethyl-4-(2 ,4-dihydroxyphenyl)-3,4-dehydropiperidine, 2,b-diethyl-4(2,4-dihydroxyphenyl)-3,4-dehydropiperidine, 2.2.6.6-titramethyl-4-(2 , 4-dihydroxyphenyl)-5,4-dehydropiperidine, 2.
2.6.6-titraethyl-4-(2,4-dihydroxyphenyl)-3,4-dehydropiperidine, 2.
Examples include 2.6.6-titrapropyl-4-(2,4-dihydroxyphenyl)-3,4-dehydropiperidine.

The 4-(2,4-dihydroxyphenyl)piperidines of the present invention are useful as stabilizers for various synthetic resins.

The synthetic resins in which the 4-(2,4-dihydroxyphenyl)piperidines are blended include polyethylene, polypropylene, °-poly-1-7'tene, poly-4-methyl-1-pentene, and ethylene/propylene copolymer. Examples include polyolefins such as ethylene/α-olefin copolymers such as ethylene/1-butene copolymers, polystyrene, polyvinyl chloride, polyester, polyamide, and polyurethane. Among these synthetic resins, it is preferable to blend the 4-(2,4-dihydroxyphenyl)piperidines as a stabilizer with polyolefins. In addition, the blending ratio of the 4-(2,4-dihydroxyphenyl)piperidines to these synthetic resins varies depending on the type of synthetic resin, but
Usually 0.01 to 10 per 100 parts by weight of synthetic resin
parts by weight, preferably in the range of 0.05 to 6 parts by weight.

Examples of the hydrogenation-reduction catalyst used in the production method of the present invention include hydrogenation-reduction catalysts used in ordinary catalytic hydrogenation-reduction reactions.

Specifically, Raney nickel, reduced nickel, nickel supported catalysts in which nickel is supported on various supports such as diatomaceous earth, alumina, pumice, silica gel, and 7-acid clay; Cobalt catalysts: Copper catalysts such as Raney copper, reduced steel, copper/supported catalysts; palladium black, palladium oxide, colloidal palladium, palladium/carbon, palladium/barium sulfate, palladium/barium carbonate, palladium/
Palladium catalysts such as magnesium oxide, palladium/calcium oxide, palladium/alumina; Platinum catalysts such as platinum/carrier catalysts such as platinum black, colloidal platinum, platinum/sponge, platinum oxide, platinum sulfide/carbon: colloidal rhodium, rhodium/carbon , rhodium catalysts such as rhodium oxide; platinum group catalysts such as ruthenium catalysts; rhenium catalysts such as nyrenium heptoxide and rhenium carbon; copper chromium oxide catalysts;
Examples include molybdenum oxide catalyst; vanadium oxide catalyst; tungsten oxide catalyst. Among these hydrogenation reduction catalysts, it is preferable to use a palladium catalyst, and it is particularly preferable to use a palladium/carrier catalyst, and it is especially preferable to use palladium/carbohydrate or palladium/alumina.

In some cases, the hydrogenation reduction catalyst may be subjected to a conventional treatment with hydrogen or an alcohol such as methanol or ethanol before being used in the reaction. The usage ratio of these hydrogenation reduction catalysts is usually 0.00 as the metal atom of the hydrogenation reduction catalyst per mole of the 4-(2,4-dihydroxyphenyl)-6,4-dehydropiperidines.
It ranges from 1 to 0.2 gram atom, preferably from 0.004 to 0.1 gram atom.

In the production method of the present invention, the reaction between the 4-(2,4-dihydroxyphenyl)-3,4-dehydropiperidines and hydrogen is usually carried out in a liquid phase under normal pressure to pressurized conditions. During this reaction, it is also possible to use a solvent that does not adversely affect the reaction. Specifically, the reaction solvent includes ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, diethylene glycol monomethyl ether, tetrahydrofuran, dioxane, dibrobyl ether, diphenyl ether nato ether, ethanol, isopropanol, ethylene glycol, Alcohols such as diethylene glycol, triethylene glycol, and propylene glycol; nitriles such as acetonitrile, propionitrile, and benzonitrile; and aromatic hydrocarbons such as benzene, toluene, xylene, mesitylene, ethylbenzene, cumene, and cymene. I can give an example. Among these solvents, it is preferable to use alcohol, and it is particularly preferable to use methanol and ethanol. The proportions of these solvents used are as follows:
, 4-dehydropiperidines is usually in the range of 0.2 to 50.

In the production method of the present invention, the temperature during the reaction is usually 15
The temperature range is from 20 to 60°C, preferably from 20 to 40°C. The 4-(2,4-dihydroxyphenyl)piperidines can be obtained by treating the mixture after the completion of the reaction according to conventional methods such as distillation, crystallization, and extraction.

Next, the present invention will be specifically explained with reference to examples.0 Example 1 In a 4-tubular flask with an internal volume of 300 ml equipped with a hydrogen blowing tube, a stirrer, a thermometer, and a cooling tube, 2.2, 6.
6-natramethyl-4-(2,4-dihydroxyphenyl)-3,4-dehydropiperidine (l[) 7.41
g (50 mmol), 1.27 g of 5% pa/carbon and 200 m# of methanol were charged under nitrogen. While maintaining the internal temperature of the reactor at 25°C, hydrogen was added at 20 J/h under normal pressure.
I blew it for 4 hours at min. After the reaction, the catalyst was separated under nitrogen, and the resulting reaction solution was analyzed by gas chromatography, and (2) was not detected at all. When methanol was distilled off from the reaction solution, 7.4 g of a white solid (melting point 256-257°C) was obtained.

This compound was determined from the following spectral data and elemental analysis data as a new compound 2,2.6.6-natramethyl-4-(2,4-dihydroxyphenyl)kebiperi-11-mass number (m#) of the parent peak in the mass spectrum: 249 infrared spectrum (KBr tablet): 3400.2950.1
600 NMR spectrum (CDC15/a6-DMSO): ■
,■,■(4,25δ,b,s, 3)T)■(6,3
5δ, 6. d, J=2.5Hz, J=i QHz,
IH)■(6,40δ,d,J=2,5H2IH)
■(6,88δ, a, a, J=10H2IH) Elemental analysis: CHN Analysis value (wt%) 72.16 9,31 5.
7312 - Example 2 A reaction was carried out under the same conditions as in Example 1 except that 0.09 g of Raney nickel was charged instead of 5% pa/carbon in Example 1.

After separating the catalyst in the same manner as in Example 1, the resulting reaction solution was analyzed by gas chromatography, and the results showed that the reaction rate of (①) was 1001 mol%, and the yield of GV) was 98 mol%. .

Example 3 (Evaluation of process stability) The stabilizers shown in Table 1 were homogeneously mixed into polypropylene powder using a Mitsui Miike Hensel mixer. 0.1 wt.
%), 28 with a 20mmφ extruder made by Thermoplastics
Melt-kneading was performed at 0°C and screw rotation at 6 rpm. And melt index (MI) before and after kneading
, 230°C, 2.161Q load, ASTM D-1238
) difference (ΔMI) was determined and used as a measure of the stabilizing effect during processing.

Table 1 (fil) Product name: Yoshitomi BHT (manufactured by Yoshitomi Pharmaceutical KK) (*2) Product name: Irganox ■ 1076 (manufactured by Ciba Geigy) (*3) Product name: Irganox ■
1010 (manufactured by Ciba Geigy) Applicant Mitsui Petrochemical Industries Co., Ltd. Agent Kazu Yamaguchi 15- 423-

Claims (2)

[Claims] (1) General formula (1) [In the formula, R1, R2, R3, R4 and R each represent a hydrogen atom or a lower alkyl group. ] 4
-(2,4-dihydroxyphenyl)piperidines. (2) General formula [I] [In the formula, R1, R2, R3, R4 and R5 each represent a hydrogen atom or a lower alkyl group. ] General formula [■] 9 [Formula Among them, R1, R2, R3, R4 and R are the same as above. ] A method for producing 4-(2,4-dihydroxyphenyl)piperidines.