CH628331A5 - Process for the preparation of novel piperidine hydroxamides - Google Patents

Description

The invention relates to a process for the preparation of new 2,2-dimethyI-6,6-dialkyl-4-hydroxy-4-carbamoylpiperi-10 dynes and their salts, and their use as stabilizers for organic materials.

The new compounds correspond to formula I.

in which R1 and R2 denote the same or different straight-chain or branched alkyl radicals having 1 to 12 carbon atoms, or R1 and R2 together with the carbon atom to which they are attached, a saturated 5- or 6-membered homocyclic ring or a Grouping of the formula h3C

CIL

(H-X)

y-

in

HN

20th

H3C

ch.

> v

OH

CONH,

CO

> -ch2V - »»

R1 R2

in which R1 and R2 mean identical or different straight-chain or branched alkyl radicals having 1 to 12 carbon atoms or R1 and R2 together with the carbon atom to which they are attached represent a saturated 5- or 6-membered homocyclic ring or a grouping of the formula

H3C

ch.

form, and HX is phosphoric acid, phosphorous acid, an aliphatic or aromatic sulfonic acid or phosphonic acid, an aliphatic mono-, di- or polycarboxylic acid or an aromatic mono- or dicarboxylic acid and m = 0 or 1, characterized in that the preparation of the compounds with m = zero is a 2,2-dimethyl-6,6-dialkylpiperidine cyanohydrin of the formula II

CH,

h3c ch.

y-v "

'V-

di)

r

R

saponified with strong mineral acids and the resulting 2,2-dimethyl-6,6-dialkyl-4-hydroxy-4-carbamoylpiperidinium salts with stronger bases or an ion exchanger into the 2,2-dimethyl-6,6-dialkyl-4 -hydroxy-4-carbamoylpiperidines are converted and, if desired, these are reacted with acids to give the products with m = 1.

2. The method according to claim 1, characterized in that compounds of formula I are prepared in which R1 and R2 are methyl groups.

3. The method according to claim 1, characterized in that 2,2,6,6-tetramethyl-4-hydroxy-4-carbamoylpiperidine, 2,2,6,6-tetramethyl-4-hydroxy-4-carbamoylpiperidinium stearate, 2,2,6,6-tetramethyl-4-hydroxy-4-carbamoylpiperidium -nium-p-tert-butylbenzoate and 2,2,6,6-tetramethyl-4-hydroxy-4-carbamoylpiperidinium succinate.

4. Use of the compounds of formula I prepared by the process according to claim 1 for stabilizing synthetic polymers against the damaging influence of light and heat in an amount of 0.01 to 5 parts by weight, based on 100 parts by weight of polymer .

NH

2 * - "CH ^ j and H-X represents phosphoric acid, phosphorous acid, an aliphatic or aromatic sulfonic acid or phosphonic acid, a 40 aliphatic mono-, di- or polycarboxylic acid or an aromatic mono- or dicarboxylic acid and m = 0 or 1.

Representative representatives of the new piperidine hydroxyamides include:

2,2,6,6-tetramethyl-4-hydroxy-4-carbamoylpiperidine 45 2,2,6,6-tetramethyl-4-hydroxy-4-carbamoylpiperidinium stearate

2,2,6,6-tetramethyl-4-hydroxy-4-carbamoyipiperidinium p-tert-butyl benzoate

2,2,6,6-tetramethyl-4-hydroxy ~ 4-carbymoylpiperidinium-50 succinate.

To prepare the new compounds, one can start from 2,2-dimethyl-6,6-dialkylpiperidones, which can be prepared by known processes (for example Beilstein Vol. 21, page 249; Francis, J. Chem. Soc. 1927, page 2897; DE- OS 1 695 753) are accessible 55. By reacting the piperidones with cyanides, the cyanohydrins of the formula II are obtained

H3c ° h-

60

oh cn

(II),

65 R1 r2

which according to the invention also in a known manner with strong mineral acids such as concentrated hydrochloric acid, to the ami

3,628,331

that are saponified. The 2,2,6,6-tetraalkyl-4-hydroxy-4-carba- lon-6.6 and nylon 6.10, polyurethanes and epoxy resins um-moylpiperidines are obtained as salts, which can be obtained using stronger bases.

e.g. Alkali solutions or suitable ion exchangers into which the amount of free bases to be added to the synthetic polymers can be converted. From these, new compounds can be made depending on the type, by reaction with acids - preferably in the presence of a 5 properties and the special applications of the too stable solvent, e.g. an alcohol or water - the sizing polymers fluctuate considerably. Generally produce desired salts. Both the free bases and 0.01 to 5, preferably 0.05 to 3 and in particular 0.1, the salts can by recrystallization from water or Al to 1.5 parts by weight, based on the amount of synthetic alcohol getting cleaned. Polymers. It can be a single connection or

In the new compounds of formula I, the R1 groups are a mixture of several used.

and R2 straight-chain or branched alkyl radicals with 1 to 12,

preferably 1 to 6 carbon atoms. R1 and R2 The incorporation of the compounds into the synthetic may be the same or different. The polymers are of particular interest and are carried out by customary methods. The stabilizer can be derived from the very easily accessible triacetonamine powder as a powder with the synthetic polymer, the compounds in which R1 and R2 are methyl groups. 15 or a solution, suspension or emulsion of the stabilizer in R1 and R2 can be incorporated together with the carbon atom to which a solution, suspension or emulsion of the synthetic poly-they are bound, also a saturated 5- or 6-membered polymer.

form homocyclic ring, e.g. a cyclohexane ring. The stabilizers are both on their own and in

HX stands for phosphoric acid, phosphorous acid, an ali mixture with conventional light stabilizers (UV stabilizers phatic sulfonic acid or phosphonic acid generally with 20 and quencher) and heat stabilizers based on phe-1 to 30, preferably 1 to 18, carbon atoms, an optionally aromatic, sulfidic and phosphorus-containing antioxidants alkylated aromatic sulfonic or phosphonic acid with in general.

generally 6 to 25, preferably 6 to 18, carbon atoms, 1 being conventional stabilizers to be understood in detail

there may be up to 3 alkyl groups with 1 to 16 carbon atoms: e.g. 2,6-di-tert-butyl-p-cresol, 3,5-di-tert-butyl-4-hy-nen. H — X can furthermore mean an aliphatic, 25-hydroxyphenylpropionic acid ester, alkylidene-bis-alkylphenol, straight-chain over-branched mono- or dicarboxylic acid with thiodipropionic acid ester of fatty alcohols and dioctadecyl generally 2 to 34, preferably 2 to 18, carbon atoms, or sulfide and disulfide. The phosphorus-containing compounds optionally also include a polycarboxylic acid with up to, for example, trisnonylphenylphosphite, distearylpentaery having up to 4 carboxyl groups and a total of up to 16 carbon atoms, thritol diphosphite, esters of pentaerythritol phosphite and others or an aromatic, optionally Q- to C4-alkyl- call so. Examples of UV absorbers are the benzotriazole or isoalkyl-substituted mono- or dicarboxylic acid with all compounds, such as 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, generally 7 to 25, preferably 7 to 19, carbon atoms , be. Im for quencher metal chelates.

In addition to the phosphoric acid already mentioned, some are an effective stabilizer combination for halogen-free

and phosphorous acid, for example: phenylphosphate-a-olefins, such as e.g. High, medium and low pressure polyphonic acid, camphorsulfonic acid, dodecylsulfonic acid, p-to-35 risate from C2 to C4-a-01efins, in particular polyethylene and luolsulfonic acid, alkyl polyglycol ether sulfonic acids, alkylaryl polypropylene or copolymers of such a-olefins, polyglycol ether Acetic acid, propionic acid, n-oc-, based on 100 parts by weight of polymer, for example tanoic acid, 2-ethylhexanoic acid, lauric acid, stearic acid, tallow, consists of 0> 01 to 5 parts by weight of one of the fatty acid, montanic acid, succinic acid, adipic acid, azelaine-using compounds, 0.05 to 5 parts by weight of a phenic acid, citric acid, tricarballylic acid, benzoic acid, tolylic acid stabilizer, optionally 0.01 to 5 parts by weight of egg -ren, p-tert-butylbenzoic acid, phthalic acid and terephthalene's sulfur-containing costabilizer, and optionally 0.01 acid. up to 3 parts by weight of a basic or neutral metal soap,

According to the invention, both the free bases and also ZB calcium stearate or zinc stearate, and, if appropriate, the salts mentioned above or, in the case of polybasic 04 to 5 parts by weight of a phosphite and optionally 0.01, acids, if appropriate, also acidic salts or Tetraalkyl 45 to 5 parts by weight of a known UV stabilizer from which 4-hydroxy-4-carbamoyipiperidines can be prepared. Group of alkoxyhydroxybenzophenones, hydroxyphenyl-means in the general formula the index “m”, the consequent benzotriazoles, salicylic acid phenol ester, Benzoic acid hydroxyphe-ge is 0 or 1. nolester, benzylidene malonic acid mononitrile ester, the so-called

The new 2,2,6,6-tetraalkyl-4-hydroxy-4-carbamoylpi “quenchers” such as nickel chelates or hexamethylene phosphorus peridines and their salts give synthetic polymer compositions 50 acid namid.

an exceptional stability against decomposition due to the stabilization of chlorine-containing vinyl homo- and

Exposure to ultraviolet radiation or heat. The copolymers, for example polyvinyl chloride, polyvinyli color properties of the polymer compositions are not adversely affected by the application chloride, polyvinyl chloroacetate, vinyl chloride-a-olefin copolymerity of the new compounds. polymers and chlorinated polyolefins, e.g. chlorinated

55 Polyethylene and polypropylene, metal compounds, epoxy stabilizers, phosphites and given polyolefins, an addition of the new Sta-Unter synthetic polymer masses, which are to be protected against the harmful agents in the presence of known effects of light and heat known as stabilizers such as Polyisoprene, polybutadiene, polystyrene, polyhydric alcohols also an improvement rol and in particular polypropylene and polyethylene lower the heat and light stability.

and high density, furthermore ethylene-propylene copolymers, Ethy- 60

Ien-butene copolymers, ethylene-vinyl acetate copolymers, sty- The metal compounds known as stabilizers, rol-butadiene copolymers and acrylonitrile-styrene-butadiene-co- are understood in this context: calcium, baripolymers. The terms “polyvinyl chloride” and “poumene, strontium, zinc, cadmium, aluminum and lead soaps lyvinylidene chloride” are intended to mean homopolymers of vinyl chloride and aliphatic carboxylic acids or oxycarboxylic acids with about 12 vinylidene chloride, copolymers of vinyl chloride and vinyli 65 bis 40 carbon atoms, salts of the metals mentioned with aromatic chloride with vinyl acetate or other olefinically unsaturated carboxylic acids such as benzoates or salicylates and (old monomers, polyacetals, polyesters, such as, for example, poly-) phenolates of these metals, furthermore organotin compounds, ethylene terephthalate , Polyamides, for example nylon-6, Ny- such as Dialkyltin thioglycolates and carboxylates.

628 331

4th

Known epoxy stabilizers are e.g. epoxidized higher fatty acids such as epoxidized soybean oil, tall oil, linseed oil or butyl oleate and epoxides of long-chain a-olefins.

Trisnonylphenyl phosphite, trislauryl phosphite or also esters of pentaerythritol phosphite can be mentioned as phosphites. 5

Polyhydric alcohols can be, for example, pentaerythritol, trimethylolpropane, sorbitol or mannitol, i.e. preferably alcohols with 5 to 6 carbon atoms and 3 to 6 OH groups.

A stabilizer combination for stabilizing halogen-containing polymers consists, based on 100 parts by weight of polymer, for example of 0.01 to 10 parts by weight of metal compounds known as stabilizers, 0.1 to 10 parts by weight of one known epoxy stabilizer, 0.05 to 10 parts by weight of a phosphite, 0.1 to 10 parts by weight of a polyhydric alcohol and 0.01 to 5 parts by weight of one of the compounds to be used according to the invention.

In the following, the process for the preparation of the new compounds is explained using a few examples, and the outstanding suitability thereof is shown as a light stabilizer in plastic compositions. 20th

example 1

2,2,6,6-tetramethyl-4-hydroxy-4-carbamoylpiperidine 60 g of triacetonamine cyanohydrin are added in portions to 180 g of concentrated hydrochloric acid at 20 to 25 ° C. with stirring. It is then stirred until a clear solution has formed (about 3 to 6 hours), which is either concentrated in vacuo until the chlorohydrate precipitates, or which is concentrated with a base such as, for example. NH3 neutralized under cooling, the hydrochloride likewise separating out. The colorless salt obtained decomposes above 307 ° C. The free base of mp 210 ° C. is obtained from the hydrochloride by treatment with aqueous or better alcoholic alkali metal solution or alcoholic ammonia.

35

Analysis calculated C 60.0% H 10.0% N 14.0%

found C 59.9% H 10.2% N 13.2%

IR: v C = 0: 1 600 cm- 1680 cm-1

40

Example 2

Example 4

2,2,6,6-tetramethyl-4-hydroxy-4-carbamoylpiperidinium succinate

The presentation is analogous to Example 2. Instead of stearic acid, 1.2 g of succinic acid are used; Mp of the salt 230 ° C.

Example 5

This example shows the light-stabilizing effect of some of the compounds obtained according to the invention when used in a poly-a-olefin.

100 parts by weight of polypropylene with a melt index i5 of approx. 6 g / 10 min. (Determined in accordance with ASTM D 1238-62 T) and a density of 0.96 g / cm3 were mixed with

0.1 part by weight of a bis (4'-hydroxy-3'-tert-butylphenyl) butanoic acid ester

0.2 parts by weight of calcium stearate and each

0.3 part by weight of the stabilizers according to the invention to be tested are mixed and homogenized on the two-roller at 200 ° C. for five minutes. The plastic melt was then pressed at 200 ° C. into a plate 1 mm thick. Test specimens according to DIN 53 455 were punched out of the cooled plate.

The test specimens required as comparison samples were produced in the same way, but without the stabilizer to be tested.

To determine the light stability, the samples were subjected to exposure to alternating light in a weathering apparatus (Xenotest 150) from Original Hanau Quarzlampen GmbH. The radiation intensity was modulated by 6IR windows and 1 UV window (DIN 53 387).

The exposure time was measured in hours (= standing time) after which the absolute elongation at break had dropped to 10%. The elongation at break was measured on an Instron tensile testing machine at a take-off speed of 5 cm / min. determined. Before the start of the exposure test, it was 850%.

The results are summarized in the table below:

2,2,6,6-tetramethyl-4-hydroxy-4-carbamoylpiperidinium stearate 5.6 g of stearic acid and 4 g of the 2,2,6,6-tetramethyl-4-hydroxy-4-carbamoylpiperidine obtained according to Example 1 45 boiled in about 20 ml of ethanol, after which you let it stand for about 1 hour. White crystals of mp 151 to 154 ° C. are obtained.

Example 3

2,2,6,6-tetramethyl-4-hydroxy-4-carbamoylpiperidinium p-tert-butylbenzoate

The preparation is analogous to Example 2. Instead of stearic acid, 3.7 g of p-tert-butylbenzoic acid are used; Mp of the salt 240 ° C.

Connection according to example ...

1

2nd

3rd

4th

without (comparison)

Service life (hours)> 3000

> 700

> 700

> 700 560

50

While using the base according to Example 1 the elongation at break was still 580% after 3,000 hours, when using a commercial product (octoxybenzophenone) the elongation at break was only 6% after 3,000 hours and when using a nickel chelate it was 18%.

C.

Claims (3)

628 331 2nd PATENT CLAIMS 1. Process for the preparation of new 2,2-dimethyl-6,6-dialkyI-4-hydroxy-4-carbamoylpiperidines and their salts of the formula I. (I), 5. Use according to claim 4, characterized in that stabilizing polyolefins. 6. Use according to claim 4, characterized in that halogen-containing polymers are stabilized. (h-x) m • hn