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CN-121986091-A - Preparation of N-alkoxyamine HALS from the corresponding hydroxylamine

CN121986091ACN 121986091 ACN121986091 ACN 121986091ACN-121986091-A

Abstract

A process is described for the preparation of a compound of the class of sterically hindered alkoxyamines, comprising the step of alkylating a sterically hindered hydroxylamine compound to the corresponding sterically hindered alkoxyamine by reacting said sterically hindered nitroxyl compound with a compound capable of generating a carbon-centered alkyl radical, typically a primary or secondary alkyl radical, selected from thermal radical initiators forming radical species in the temperature range of 40 ℃ to 200 ℃ and selected from photoinitiators which undergo photoexcitation upon irradiation with UV light or visible light in the range of 180 to 700 nm, in particular in the range of 180 to 380 nm, the compound capable of generating a carbon-centered alkyl radical is typically selected from the group of organic peroxides, azo compounds, benzoyl derivatives, benzophenone derivatives, thioxanthone derivatives, benzoin derivatives, benzoylphosphine oxide derivatives, for example from the group of diacyl peroxides of formula (A), peresters of formula (A) and oxalic acid peresters R-CO-O-Z-R (A) of formula (D), R-Z '-X-CO-CO-O-Z' -R (D) wherein each R independently represents a primary or secondary alkyl or cycloalkyl group preferably containing from 1 to 15 carbon atoms and X is an oxy-O-or peroxy-O-O-, Z represents CO or an alkylene group bonded to a quaternary carbon atom, the quaternary carbon atom is an alkylene group of formula (C) R ' -C-R ' (C), wherein each R ' is selected from alkyl groups of 1 to 15 carbon atoms, Z "represents said alkylene group bonded to the quaternary carbon atom of formula (C). The described process yields the corresponding O-alkylated derivatives of the sterically hindered hydroxylamines, typically of the class of compounds known as N-O-alkyl HALS, with extremely high selectivity and conversion without the use of catalysts, especially metal catalysts.

Inventors

  • Alessandro Zeda

Assignees

  • 基因化学股份公司

Dates

Publication Date
20260505
Application Date
20240823
Priority Date
20230927

Claims (15)

  1. 1. A process for alkoxylating a sterically hindered hydroxylamine compound, characterized in that its nitrogen atom is bonded to 2 tertiary carbon atoms, to the corresponding sterically hindered alkoxyamine, which comprises reacting said sterically hindered hydroxylamine compound Is reacted with a compound capable of generating a carbon-centered alkyl radical, The compound capable of generating a carbon-centered alkyl radical is selected from A thermal radical initiator that forms radical species in a temperature range of 40 ℃ to 200 ℃, and Photoinitiators which undergo photoexcitation when irradiated with UV light in the range of 180 to 700 nm or visible light, especially in the range of 180 to 380 nm, The compound capable of generating a carbon-centered alkyl radical is selected from the class of compounds generating primary or secondary alkyl radicals, And/or from the class of organic peroxides, azo compounds, benzoyl derivatives, benzophenone derivatives, thioxanthone derivatives, benzoin derivatives, benzoylphosphine oxide derivatives.
  2. 2. The process of claim 1, wherein the compound capable of generating a carbon-centered alkyl radical is selected from the group consisting of diacyl peroxides of formula (A), peresters of formula (A), and oxalic acid peresters of formula (D) R-CO-O-O-Z-R(A), R-Z”-X-CO-CO-O-O-Z”-R(D), Wherein each R independently represents a primary or secondary alkyl or cycloalkyl group preferably containing 1 to 15 carbon atoms, and X is oxygen-O-or peroxy-O-O-, Z represents CO or an alkylene group bonded to a quaternary carbon atom which is an alkylene group having the formula (C) R’-C-R’(C) Wherein each R' is selected from alkyl groups having 1 to 15 carbon atoms, Z' represents the alkylene group bonded to a quaternary carbon atom having the formula (C).
  3. 3. The method of claim 1 or 2, wherein the sterically hindered hydroxylamine compound comprises one or more moieties 1-hydroxy-2, 6-tetramethyl-piperidine of formula (IIIa), wherein the asterisk indicates the position of the bond linking the moiety to another moiety of the molecule (IIIa) And the corresponding sterically hindered alkoxyamine compounds belong to the class of 1-alkoxy-2, 6-tetramethyl-piperidines containing one or more moieties of formula (Ia), wherein the asterisks indicate the position of the bond connecting these moieties to another moiety of the molecule (Ia) Wherein R is as defined in claim 2.
  4. 4. A process according to claim 3, wherein the sterically hindered alkoxyamine compound corresponds to formula (Ib) (HA) p Y(Ib) Wherein the method comprises the steps of HA is a sterically hindered amine ether moiety (HE) having the formula (Ia); p is a number in the range of 1 to 6, And wherein Y is an anchor group having a valence of 2 to 6 of formula (IX) T 3 -(N[T 4 ]-A 2 ) q -N[T 1 T 2 ](IX) Wherein q is in the range of 0 to 3, Or Y is an anchor group as further defined below; When p is a number of times 1, Y is an anchor group having the formula-NR 1 -A 1 ; when p is 2, Y is an anchor group having the formula DC-A 2 -DC; or Y is said divalent anchoring group having the formula (IX), wherein Q is 0, T 3 represents an open bond, T 1 is as defined for R 1 and T 2 is a divalent aminotriazinyl group of formula (X) (X), Or q is 1, each of T 1 and T 3 is as defined for R 1 and each of T 2 and T 4 is said divalent aminotriazinyl of formula (X); When p is 3, Y is a trivalent anchoring group of the formula (IX) wherein q is 0, T 3 represents an open bond, T 1 is a trivalent diamino triazinyl group as defined for R 1 and T 2 is of the formula (XI) (XI), Or q is 1, T 1 is as defined for R 1 , T 2 is a divalent aminotriazinyl group having the formula (X), and T 3 and T 4 independently represent an open bond or a divalent aminotriazinyl group having the formula (X); When p is 4, Y is a tetravalent anchor group of formula (IX) wherein q is 3 and two of T 2 and residue T 4 represent a divalent diamino triazinyl group of formula (XI), while each of T 1 and T 3 and the remaining residue T 4 are as defined for R 1 ; When p is 5, Y is a pentavalent anchoring group of the formula (IX), wherein q is 1, T 1 is a trivalent diamino triazinyl group of the formula (XI), T 3 is a divalent amino triazinyl group of the formula (X), and T 2 and T 4 independently represent an open bond or a divalent amino triazinyl group of the formula (X); When p is 6, Y is a hexavalent anchoring group having the formula (IX), wherein Q is 1, each of T 1 and T 3 is a trivalent diamino triazinyl group of formula (XI), and T 2 and T 4 independently represent an open bond or a divalent amino triazinyl group of formula (X); Or q is 2 and T 2 and each T 4 represent a trivalent diamino triazinyl group having the formula (XI) and each T 1 and T 3 are as defined for R 1 ; Or q is 3 and two of T 2 and these residues T 4 represent a trivalent diamino triazinyl group of formula (XI), while each T 1 and T 3 and the remaining residues T 4 are as defined for R 1 ; Or q is 3 and T 2 and T 3 and one of these residues T 4 represent a trivalent diamino triazinyl group of formula (XI), while each T 1 and the remaining residue T 4 are as defined for R 1 ; A 1 is C 1 -C 12 alkyl or C 2 -C 12 alkyl interrupted by O or COO; A 2 is C 2 -C 12 alkylene; DC is a divalent linking moiety that is linked to the base moiety, typically a direct bond, an ester moiety-COO-, an ether moiety-O-, or an amino moiety having the formula-NR 1 -; and R 1 is H or C 1 -C 8 alkyl, especially C 1 -C 6 alkyl, and X is Cl or N (R 1 ) 2 ; Or the sterically hindered hydroxylamine compound is an oligomeric or polymeric compound comprising 6 or more, especially 7 or more, more especially 7 to 100 moieties of the formula (Ia) and/or (IIIa), wherein at least one moiety of the formula (Ia) is present.
  5. 5. The process of claim 1 or 2 or 3 or 4, wherein the alkyl moiety of the sterically hindered alkoxyamine and/or R in formula (A) or (D) is independently selected from methyl, ethyl, 1-propyl, 2-propyl, 1-butyl, 2-butyl, 1-pentyl, 2-pentyl, 3-pentyl, 1-hexyl, 2-hexyl, 3-hexyl, 1-heptyl, 2-heptyl, 3-heptyl, 4-heptyl, 1-octyl, 2-octyl, 3-octyl, 4-octyl, nonyl, decyl, undecyl, dodecyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, cycloundecyl, cyclododecyl, especially wherein two residues R represent the same group.
  6. 6. The process of claim 1 or 2 or 3 or 4 or 5, wherein the reaction is carried out at a temperature in the range of 0 ℃ to 140 ℃, e.g. 0 ℃ to 120 ℃, and in particular in the presence of an inert solvent.
  7. 7. The process of any of the preceding claims, wherein the compound capable of generating a carbon-centered alkyl radical is a diacyl peroxide of the formula (a) or an oxalic acid perester of the formula (D) and the reaction is carried out at a temperature in the range of 15 ℃ to 100 ℃, especially 30 ℃ to 100 ℃, or the peroxide is a perester of the formula (a) and the reaction is carried out at a temperature in the range of 30 ℃ to 140 ℃, especially 50 ℃ to 140 ℃.
  8. 8. The method of any one of the preceding claims, wherein the reaction is carried out for a period of 5 minutes to 100 hours and/or the reaction is carried out in the absence of a heavy metal catalyst and/or wherein the reaction is carried out under a shielding gas that does not comprise oxygen, for example under nitrogen.
  9. 9. The process as claimed in any of the preceding claims, wherein the reaction is carried out in the presence of a solvent selected from nonpolar solvents like C5-C12 hydrocarbons, such as alkanes, cycloalkanes, aromatic hydrocarbons or arylalkanes, optionally dried, and polar solvents like alcohols, ethers, esters, such as tert-butanol, methyl tert-butyl ether, methyl acetate, tert-butyl acetate, especially comprising methyl and/or tert-alkyl moieties, and mixtures of nonpolar solvents and polar solvents.
  10. 10. A process according to any one of claims 3 to 9, wherein the sterically hindered alkoxyamine obtained in said process is a compound having formula (I) (R 2 ) 3 -C-N(OR)-C-(R 2 ') 3 (I) Wherein R is as defined in any one of claims 2 or 5; Each of R 2 and R 2 ' is a hydrocarbon, and preferably R 2 and R 2 ' are linked to each other to form a divalent hydrocarbon residue, all R 2 and R 2 ' together contain 2 to 500 carbon atoms and optionally further contain one or more moieties selected from the group consisting of tertiary nitrogen moieties, secondary nitrogen moieties, ester moieties COO; And preferably wherein R is an alkyl group selected from C 1 -C 12 alkyl OR C 5 -C 8 cycloalkyl, and each R 2 is a hydrocarbon, and preferably is linked to each other to form a divalent hydrocarbon residue, the two R 2 s together contain 2 to 500 carbon atoms and optionally one OR more tertiary nitrogen moieties, one OR more ester moieties COO, and/OR one OR more divalent moieties > N-OR; And most preferably wherein the sterically hindered hydroxylamine compound belongs to the class of 1-hydroxy-2, 6-tetramethyl-piperidines containing one or more moieties of the formula (IIIa) and the corresponding sterically hindered alkoxyamine compound belongs to the class of 1-alkoxy-2, 6-tetramethyl-piperidines containing one or more moieties of the formula (Ia), wherein the asterisks indicate the position of the bond linking these moieties to another part of the molecule (Ia) (IIIa) And R is an alkyl group selected from C 1 -C 12 alkyl or C 5 -C 8 cycloalkyl.
  11. 11. A process for the preparation of sterically hindered alkoxyamine compounds as claimed in any of the preceding claims which conform to the formula (XIV) or (XV) (XIV) (XV) Wherein R, R 1 is as defined in the preceding claims, and Z is hydrogen OR OR OR OCOR OR N (R 1 ) R OR oxo; or bis (1-octyloxy-2, 6-tetramethylpiperidin-4-yl) sebacate; Or an oligomeric or polymeric compound comprising at least 6, for example 6 to 100, moieties of formula (Ia), wherein the asterisks indicate the position of the bond linking these moieties to another moiety of the molecule (Ia); For example, the product of CAS number 191680-81-6 having the formula , Wherein the N4-amine is a trivalent amine of the formula XHN-CH 2 CH 2 CH 2 -NX-CH 2 CH 2 CH 2 -NX-CH 2 CH 2 CH 2 -NHX, Wherein 1 symbol X represents hydrogen and 3 symbols X represent bonds; Oligomeric or polymeric sterically hindered alkoxyamine compounds preferably corresponding to one of the formulae (IV) or (V) (IV), Wherein a 2 is C 2 -C 12 alkylene; r 1 is H or C 1 -C 8 alkyl, especially C 1 -C 6 alkyl, and And R is as defined below for formula (V), Wherein n is in the range of 1 to 10 And R is as defined in claim 1 or 3, and is preferably C 1 -C 5 alkyl, especially 1-propyl.
  12. 12. The process of any one of claims 1 to 11, wherein the sterically hindered hydroxylamine compound is represented by one of the formulae (IV) or (V) (IV), Wherein a 2 is C 2 -C 12 alkylene; R 1 is H C 1 -C 8 alkyl, especially C 1 -C 6 alkyl, and R is as defined in claim 1 or 3, and is preferably C1-C5 alkyl, especially 1-propyl; (V) wherein n is in the range of 1 to 10 and R is as defined above; or a CAS number 191680-81-6 of the formula , Wherein the N4-amine is a trivalent amine of the formula XHN-CH 2 CH 2 CH 2 -NX-CH 2 CH 2 CH 2 -NX-CH 2 CH 2 CH 2 -NHX, Wherein 1 symbol X represents hydrogen and 3 symbols X represent bonds; And wherein one or more of the residues O-R or O-cycloalkyl are replaced by hydroxy.
  13. 13. A process according to any one of the preceding claims, wherein in a first step (i) and optionally a second step (ii), a sterically hindered secondary amine educt typically comprising one or more moieties 2, 6-tetramethyl-piperidin-4-yl is converted into the sterically hindered hydroxylamine compound, which is subsequently converted into the sterically hindered alkoxyamine, said process comprising (I) Contacting the secondary hindered amine educt with a suitable oxidizing agent to obtain a sterically hindered oxyamine or sterically hindered hydroxylamine; (ii) Optionally contacting the sterically hindered oxyamine obtained as the oxidation product of step (i) with a reducing agent to obtain a sterically hindered hydroxylamine, and then (Iii) Reacting the sterically hindered hydroxylamine obtained in step (i) or alternatively in step (ii) according to any of claims 1 to 12 with a compound capable of generating a carbon-centered alkyl radical; And wherein preferably the secondary amine educts are oligomeric or polymeric compounds comprising at least 6, in particular 6 to 100, moieties of 2, 6-tetramethyl-piperidin-4-yl, Such as a compound selected from the group consisting of Educt 2 having the formula: Wherein n is in the range of 1 to 10; educt 3 having the formula: wherein n is in the range of 1 to 10, especially 4 to 5; Educt 4 of the formula: CAS number 90751-07-8; educt 5 having the formula: , Educt 8 having the formula: CAS number 199237-39-3; Educt 9 of the formula: wherein R is a moiety having the formula CAS number 136504-96-6; Educts 15 having the formula: 。
  14. 14. An oligomerization or polymerization product comprising a compound comprising at least 10, such as 10 to 100, moieties of formula (Ia), wherein the asterisks indicate the position of the bond that connects the moieties to another moiety of the molecule, (Ia); Oligomeric or polymeric sterically hindered alkoxyamine compounds preferably corresponding to formula (V) Wherein n is in the range of 3 to 10 And R is as defined in claim 2, and is preferably C 1 -C 5 alkyl, especially 1-propyl; Characterized in that the oligomerization or polymerization product is obtainable by the process according to any of claims 1 to 13 or, in the case where the product is represented by formula (V), alternatively, by the process according to claim 14.
  15. 15. A compound represented by the formula (V'), Wherein n is in the range of 1 to 10 and R is hydrogen or C 1 -C 5 alkyl, provided that at least one moiety R is hydrogen; and preferably of formula (V) according to claim 15, characterized in that it contains more than 87%, typically from 90% to 99.9%, in particular from 96% to 99.9%, of the N-O moiety in alkylated form as N-OR, where R is a C 1 -C 5 alkyl group, in particular 1-propyl, and contains the remaining part R as hydrogen.

Description

Preparation of N-alkoxyamine HALS from the corresponding hydroxylamine The present invention relates to a novel process for alkylating certain N-hydroxy secondary amines and preparing the corresponding N-alkoxyamines in high purity. More specifically, the novel chemical process involves the preparation of such sterically hindered N-alkoxyamines by selective O-alkylation of hydroxylamine by reaction with certain free radical generators. Some novel compounds obtainable by the present process are further described. The products of the process can be used in various fields of chemistry and polymer technology, an important class of products being sterically hindered amines, which are generally used in polymer technology, for example as flame retardants, polymerization regulators, or as stabilizers for organic materials such as organic polymer compositions against degradation caused by light, oxygen and/or heat. Many publications describe the use of specific sterically hindered amine compounds, also known as Hindered Amine Light Stabilizers (HALS), as stabilizers for stabilizing organic materials. For use as stabilizers, such compounds may contain unsubstituted nitrogen (NH-HALS) or substituted nitrogen (e.g. N-alkyl HALS), an important class being HALS compounds which, due to the specific properties of these compounds such as reduced basicity, carry a further organic substituent attached to the oxygen atom (typically N-O-alkyl HALS, see e.g. US-5204473, US-5096950), such N-O-alkyl HALS compounds are also referred to as sterically hindered amine ethers. Other applications of sterically hindered amines, in particular N-O-alkyl HALS, include use as flame retardants, rheology modifiers, free radical initiators for controlled polymerization (see also nitroxyl radicals and nitroxylethers outside Nitroxyl radicals and nitroxyl ethers beyond stabilization: radical generators for efficient polymer modification [ stabilization: free radical generators for efficient polymer modification ], rudolf Pfaendner, C.R. Chimie [ Proc. Natl. Acad. Sci.flaccid. Sci. Chem., chem. ] 9 (2006) 1338-1344). Most commercial applications of sterically hindered N-alkoxyamines require a well-defined thermal stability of the product. As is well known in the scientific literature, the carbon-oxygen bond of sterically hindered N-alkoxyamines has a low bond energy, and properties like thermal stability or dissociation are determined by this bond strength. As described in the above references, thermal degradation of certain N-alkoxyamines (especially N-O-alkyl HALS) used as flame retardants or in rheology modifier applications is designed to occur at the desired temperatures. Typically, at extrusion temperatures, the radical reaction between the N-alkoxyamine and the molten polymer is triggered. This results in polymer chain breakage or crosslinking, which alters both the rheology of the molten polymer and the mechanical properties of the resulting final plastic article. For such applications, the R groups of the N-alkoxyamines in the flame retardants and rheology modifiers are selected as R substituents having a lower thermal stability than the light stabilizers. In contrast, N-alkoxy derivatives are typically designed to have the highest thermal stability possible to avoid any change in the rheology or mechanical properties of the plastic article for light stabilization applications. For the above reasons, in order to manufacture products based on sterically hindered N-alkoxyamines with a well-defined thermal stability, it is highly desirable to use a general process which is applicable to a wide range of sterically hindered N-alkoxyamines with a range of different R substituents and which is capable of high yields and high selectivities in the desired N-alkoxyamines. In fact, many known manufacturing processes for N-alkoxyamines have a low selectivity for the desired product, leading to the formation of undesired by-products like sterically hindered amines showing N-oxy or N-hydroxy functions, or the presence of unreacted educt materials such as secondary amine moieties. Such products may exhibit thermal stability or activation temperatures outside of the desired temperature range. This is even more important in the case of molecules with multiple sterically hindered amine moieties (like oligomeric HALS stabilizers, precursors of flame retardants or rheology modifiers) where such by-products cannot be isolated by purification and become part of the final product, with potential negative impact on the thermal stability and color of the product. It is desirable to use a manufacturing process that has high productivity, low cost and is based on green chemistry principles, especially free of heavy metals. Many sterically hindered hydroxylamines, their use as stabilizers, especially in coating compositions, and some of their preparation are described, for example, in EP-A-309401. Secondary or hindered amine precursors are largely commercially availa