SU792859A1 - N-oxide dimer 2,2,6,6-tetramethylpiperidyl-4-fulven as inhibitor of polymerization ot vinyl monomer - Google Patents

Abstract

N-oxide dimer 2,2,6.6-tetramethylpiperidyl-4-fulvene formula. tf-H "/ ™ J VjXCHs, or as an inhibitor of the polymerization of vinyl monomers.

Description

This invention relates to a novel chemical compound, specifically to the 2,2,6,6-tetramethylpiperidyl-4-fulvene N-oxide dimer of formula

NSSN

n

which can be used as an inhibitor of the polymerization of vinyl monomers.

The closest in structure and action to this compound are stable iminoxyl radicals derived from triacetoyamine.

However, the indicated iminoxyls and methods for their preparation have a number of significant drawbacks that make them difficult to use in industry: volatility and low boiling points; the use of expensive and scarce materials, for example, hydrazine hydrate, is not high enough inhibitory ability.

The proposed N-oxide dimer TMPP, which has an increased inhibitory ability during the polymerization of vinyl monomers, is obtained by condensation of 2,26,6-tetramethyl-4-oxopiperidine (triacetonamine) with cyclopentadiene in an alcohol medium when heated to 30XI 80 ° C in the presence of alkaline agents. the following oxidation of the condensation product with hydrogen peroxide.

The molar ratio of triacetonamine to

SP h cyclopentadiene 1: 1-1,5: 1. The condensation is carried out in the presence of a 1.5-10% aqueous solution of alkali in aliphatic alcohol. The amount of catalyst is 2–20% (preferably 3–7%) by weight of triacetonamine. Heating is carried out for 2 hours at 30 ° C and 2-4 hours at 80 ° C. Molar, the ratio of hydrogen peroxide to product (calculated on the NH-group) 2: 1-3.5: 1. The reaction time is 2-3 hours.

In the resulting resin, the degree of oxidation of amino groups is 40-85%, the content of N-0group is 3-10 wt.%.

The resin obtained by this method is an oxidized dimer

TMPF, which is confirmed by the data of elementary analysis, the determination of molecular weight, IR, UV and EPR spectroscopy,

IR spectrum of TMPF N-oxide oligomer mol, mass 412 (liquid paraffin, device UR-20), cm 12004300 (C-N.N-0); 1365-1380 (С СНзСНз); 1640 (C C – C C); 2850-2980 (C-H); 3000-3500 (NH), UV spectra of TMPP and its N-oxide oligomer TMPF (molecular weight 412) are recorded on a Hitachi spectrophotometer, model 323, ranging from 200 to 340 mm in 1 cm thick quartz cuvettes at 20 ± 1 ° C

The UV spectrum of TMPP in 0.1 n hydrochloric acid with Amax2b3 is analogous to the typical spectrum of dimethyl fulvene. The study of the spectrum of the obtained resin indicates the formation of a TMPP dimer, which is confirmed by the disappearance of the band with Yamax 283 nm, corresponding to fulvene, and the appearance of a new band with Yamax, 242 nm, corresponding to tetrasubstituted diene (C – C – C). The EPR spectrum of the TMPP N-oxide dimer (molecular weight 412) was taken on an IES-ME 3-X instrument at a frequency of 9.6 GHz. The EPR-spectrum is a triplet characteristic of iminoxyl radicals (a solution of the TMPP N-oxide resin in tetrachloride carbon, g 2,0046, and i 16G).

Example 1, The reaction flask is charged with a solution of NaOH in butyl alcohol, 18.9 g (0.122 g-mol) of trancetaminamine and 8.1 g (0.122 g-mol) of cyclopentadiene. The mixture is heated for 2 hours at 30 ° C and then for another 2 hours at 80 ° C, then rinsed, 2 times with 20 ml of water.

36.8 g of the resulting solution (the content of the NH groups in the solution is 1.3%) is heated to and 10 ml of 30% hydrogen peroxide are added over 30 minutes. The mixture is kept for 5 hours at 90 ° C. the oily layer is separated, washed with water and, after distilling off the solvent under vacuum, a yellow-red crystalline resin is obtained. Yield 90%. The degree of oxidation of NH-rpynn is 45%, m.p. 150 ° C (dec,), molecular weight 412, content) MO groups 5.7%.

Found%: C 79.6; H 9.8; N 6.5. According to the elementary analysis, the determination of the molecular weight. The UV, IR and EPR spectroscopy of the resin corresponds to the oxidized TMPF dimer, C28Nad N202.

Molecular mass: 436; Calculated,%: C 77.1; H 9.2; N 6.4. EXAMPLE 2 A mixture obtained by condensation of triacetonamine with cyclopentadiene under the conditions of Example 1 is washed.

water, distilled butyl alcohol and the product is subjected to heat treatment for 2 h at 150 ° C. A light yellow crystalline resin is obtained; the MH groups of the molecular

mass 400, containing 6.95%.

13 MP of trimethyl carbinol are added to 3.7 g of the obtained resin, and 3.5 ml of 30% hydrogen peroxide is added dropwise to 50 ° C. The mixture is kept for 3 hours at 85 ° C. diluted with water, the oil layer was extracted with chloroform and dried with magnesium sulfate. After distilling off the solvent under vacuum, a yellow-red crystalline resin is obtained.

5 Yield 2.9 g (85%). The degree of oxidation of LH groups is 85%. Content) M-0 groups 9.8%. Molecular weight 422 (by calculation 436). M.p. 135 ° C (decomp.).

Found %: C, 77.8; H 9.4; N 6.45.

.0, Calculated,%; C 77.1; H 9.2; N 6.4.

Example 3. Determination of the inhibitory activity of the N-oxide oligomer of TMPP under conditions of styrene release.

In a round flask equipped with

5 thermometer, siphon and reflux condenser, load 150 ml of freshly distilled styrene and an inhibitor. In the system a residual pressure of 20-40 mm Hg is created. Mixing is carried out by

0 supply of nitrogen through the siphon. The contents of the flask are heated to 120 ° C. After 4 hours of heating, the amount of polymer is determined by distilling a portion of the sample under vacuum from the lungs.

5 hydrocarbons, including non-polymerized styrene. The non-distillable residue is taken as a polymer. The obtained data on the inhibitory activity of N-oxide oligomer TMPF are given in

0 tab.1. For comparison, data on the inhibitory activity of the known inhibitors of sulfur N-nitrosone diphenylamine are given under comparable conditions.

Example 4: Determination of the inhibitory activity of the TMPP N-oxime oligomer under conditions of isolation of isoprene by rectification.

A vial of molybdenum glass is loaded with 30 ml of isoprene containing an inhibitor, the ampule is flushed with technical nitrogen containing 0.03–0.04 vol.% Of oxygen, and soldered in a stream of nitrogen.

For comparison, an isoprene containing no known inhibitor, such as M-isopropyl-M-phenyl-p-phenyleidiamine (diafen OP) and p-tert-butylpyrocatechin (pTiBK), is poured into the vial. Temperature 100 ° C. The obtained data on the inhibitory activity of the N-oxide oligomer TMPP and known inhibitors are given in table 2.

The data presented in tab.1 show that the proposed compound as an inhibitor of the thermopolymerization of styrene significantly exceeds in its inhibitory properties known inhibitors, for example sulfur, by a factor of 2, N-nitrosodiphenylamine by 15 times. The proposed inhibitor has a low volatility, has a high boiling point.

(400 ° G), which has significant advantages when used in vacuum rectification conditions.

The results listed in Table 2 indicate that the N-oxide OLI homer of TMPP under conditions of isolation of diene hydrocarbons by distillation is not inferior in its inhibiting properties to the known inhibitors of p-TBA and diaphene OP.

0

Table 1

table 2

Claims (1)

Ν-oxide dimer 2,2 * .6,6'-tetramethylpiperidyl-4-fulvena formula as an inhibitor of the polymerization of vinyl monomers.