DE2146075A1 - 2-hydroxy-benzophenones prepn - products useful as uv absorbers - Google Patents

Abstract

Cpds. of formula:- A and B can be substd, are produced from corresp. cpd. having subst. -OR (R = alkyl) by acid treatment to hydrolyse -OR to -OH, or by acylating a cpd. of formula (Z), bond is H with a cpd. producing the gp. Y or by re-arranging the cpd. of formula: (Z), OH is OY, bond is H[.

Description

Process for the production of new 2-hydroxy-benzophenone compounds.

The invention relates to three processes for the preparation of new 2-hydroxy-benzophenone compounds of the formula wherein the benzene nuclei A and B can be substituted.

The first Verrahren is characterized in that one in a compound of the formula where R is an alkyl radical, the radical R is replaced by hydrogen by treatment with acids. This is a partial ether cleavage in that in a compound of the formula (II) only the alkylaryl ether group is cleaved without changing the diaryl ether group at the same time. Protonic or Lewis acids can be used for this ether cleavage, such as, for example, hydroiodic acid, hydrobromic acid, sulfuric acid, nitric acid, pyridine hydrochloride, zinc chloride, tin tetrachloride, boron trifluoride, boron trichloride and, in particular, aluminum chloride or aluminum bromide. The reaction conditions for such ether cleavages are summarized by H. Meerwein in Houben-Weyl, Methods of Organic Chemistry, 4th Edition, Volume VI /), Oxygen Compounds I, Part 3, pages 145-160.

The starting materials of the formula (II) used in the present process are new. They can be obtained by acylating a compound of the formula with one the rest of the formula donating compound according to the Friedel-Craftsbzw method.

according to a special variant of it, e.g. that of Ilouben-Hoesch.

The preferred embodiment of this production process for compounds of the formula (I) consists in that it is carried out directly in the reaction mass which is obtained in the synthesis of the starting materials of the formula (II). This procedure has the advantage that the compounds of the formulas (II) and (I) are prepared one after the other in the same reaction vessel without having to work up after the synthesis of a compound of the formula (II). This saves not only work but also reagents, because the same catalysts, preferably aluminum halides, are very suitable for both stages in this reaction sequence. Because when converting the radical R in the formula (II) is converted into the corresponding alkyl halide, a side reaction may occur in this reaction in that this alkyl halide, in particular in the benzene nucleus A of the formula (I), has an alkylating effect in the presence of the Friedel-Crafts catalyst . If this side reaction is to be avoided, solvents which react particularly easily with alkyl halides, for example meta-xylene, can be used in the reaction.

The second process for the preparation of compounds of the formula (I) is characterized in that a compound of the formula acylated by the Friedel-Crafts method with a compound which donates the remainder of the formula (IV). Such compounds are, for example, the carboxylic acids of the formula or their functional derivatives acidic, their lialogenide, symmetrical anhydrides, asymmetrical anhydrides with other carboxylic acids or with sulfonic acids. If you acylate with the free acids of the formula (VI), you can use anhydrous zinc chloride as a catalyst (Hencki reaction). Better results are generally obtained with boron fluoride or polyphosphoric acid. The reaction conditions and the most suitable catalysts for the various functional derivatives are generally known; See, for example, the summary in Olah, "Friedel-Crafts and related reactions" Volume III, pages 1 to 36, (1964). Compounds which donate a radical of the formula (IV) are also the nitriles of the formula Their reaction with compounds of the formula (V) takes place according to a variant of the Friedel-Crafts acylation, which is referred to as the Houben-Hoesch synthesis. The conditions and catalysts used in this synthesis are known. They are summarized in the above-mentioned book by Olah: Volume III, pages 383 to 435.

The third process for the preparation of compounds of the formula (I) is characterized in that a compound of the formula is obtained surrounded. The conditions under which this rearrangement, referred to as the 1, Fries reaction, is carried out are known. A summary of this has appeared in the above-mentioned book by Olah: Volume III, pages 499 to 533.

As substituents in the benzene nuclei A and B of the formula (I) come for example in question: straight-chain or branched alkyl and alkoxy radicals or Halogen, especially chlorine or bromine. Examples of the different types of Substituents, their number and position in the benzene nuclei A and B are in the Tables 1 and 2 below are compiled. There are also the maxima the absorption spectra in the UV range (t max) of the compounds in question, because there is a connection between the absorption spectrum and the effect as Protective agent against UV light, the invention also relates to the new compounds of formula (I) and their use as UV absorbers.

For this purpose the new connections are made sensitive to light Substances incorporated or as a protective layer on the substances to be protected applied. Preserve by absorbing the harmful ultraviolet rays the new compounds used in this way protect the light-sensitive substances from destruction. The possible applications in the plastics sector are particularly numerous. The usage is used, for example, for the following plastics: cellulose acetate, cellulose acetobutyrate, Polyethylene, polypropylene, polyvinyl chloride, polyvinyl chloride acetate, polyamides, Polystyrene, ethy, lcellulose, cellulose nitrate, polyvinyl alcohol, silicone rubber, Cellulose propionate, melamine-formaldehyde resins, urea-formaldehyde resins, allyl casting resins, Polymethyl methacrylate, polyester and polyacrylonitrile.

Natural substances can also be protected from UV light, for example Rubber, cellulose, wool and silk.

The substances to be protected can be in the form of plates, rods, coatings, Foils, films, tapes, fibers, granulates, powders and in other processing forms or as solutions, emulsions or dispersions. The Einverleibur6g or the materials to be protected are coated according to methods known per se. A particularly important application method is the intimate mixing of a Plastic, for example from polypropylene in granulate form with the new compounds, e.g. in a kneader, and in the subsequent extrusion. Man In this way gets a very homogeneous mixture, what good protection important is. When extruding one obtains foils, tubes or for example Threads. The latter can be woven into textiles. In this way of working the UV absorber before processing into a textile material with the polypropylene mixed. However, you can also use textile threads and textile fabrics with the new UV absorbers treat, for example in an aqueous liquor, which is a very finely dispersed Contains compound of formula (I). Textiles are suitable for this process Polyethylene terephthalate and cellulose acetate.

Plastics do not necessarily have to be polymerized or

be condensed before mixing with the new compounds he follows. You can also use monomers or prepolymers or precondensates with the Mix the new UV absorbers and only afterwards the plastic in the final Convert form by condensing or polymerizing.

The new UV absorbers can not only be used to create clear films, To stabilize plastics and the like, they can also be used in opaque, semi-opaque or translucent materials are used, whose Surface is sensitive to degradation by ultra-violet light. examples for such materials are: foamed plastics, impermeable films and coatings, opaque Papers, clear. And opaque colored Plastics, fluorescent pigments, polishes for automobiles and furniture, creams and lotions and the like, whether opaque, clear, or translucent are.

Compared to the closest related 2-hydroxybenzophenones, the new compounds are more thermally stable, more stable, more soluble or in the ones to be protected Materials fixed in a way that prevents migration, which is why a long-lasting protection against light and warmth is attainable.

The compounds of the formula (I) can also be used together with other light stabilizers or with stabilizers. Such active ingredient mixtures often have a synergistic effect and protect the treated materials at the same time against ultra-violet radiation, heat and oxidative degradation.

To achieve protection against ultra-violet radiation, it is not absolutely necessary, the new connections to the materials to be protected incorporate or coat them with it, for example, one can use light-sensitive Slit foods like fruits, edible fats, and butter by wrapping them in plastic wrap also shows which compounds of the formula (I) contain.

The present invention also relates to the materials which to protect against ultra-violet radiation compounds the Folmel (r) included. As shown in a few examples above, the incorporation of the new compounds in the materials to be protected in some processing stage be carried out according to methods known per se, the amount of protective agents incorporated can vary within wide limits, e.g. between 0.01 and 5fi, preferably between 0.05 to 1%, based on the materials to be protected.

In the following examples, F is the melting point, Kp is the boiling point, # Wavelength, # max is the wavelength or the wavelength range at which the Light absorption is greatest, the parts are parts by weight and the percentages are percentages by weight. The temperatures are given in degrees Celsius.

Examples of the preparation Example 1 80 parts of 3-methoxydiphenyl ether (0.4 mol) and 56.2 parts of benzoyl chloride (0.4 mol) are in 320 parts of chlorobenzene solved. While stirring vigorously, the solution is added at 50 to 0 ° within 1.5 Hours in portions with 70.4 parts of aluminum chloride. Leave the mixture react at room temperature until the theoretical Amount of hydrogen chloride has evolved.

The mixture is then heated to 900 to 950 for 4 hours to achieve the To convert methoxy group into the hydroxyl group. Then the reaction mass mixed with ice water containing hydrogen chloride at room temperature, the. organic Phase separated, washed neutral and the solvent was distilled off.

The residue, 88 g of a thick, yellow-brown oil, is crude 2-hydroxy-4-phenoxy-benzophenone ' after dissolving in chlorobenzene, filtering through a column of aluminum oxide, evaporation and crystallization from gasoline in the form of colorless needles that melt at 64-650 is obtained.

Example 2 Obtained in a manner analogous to that described in Example 1 by reaction according to Friedel-Crafts from 3-methoxydiphenyl ether and p-chlorobenzoyl chloride the 2-hydroxy-4-phenoxy-4 'chlorobenzophenone in the form of colorless, at 125-127 ° melting crystals.

Example 2 Obtained in a manner analogous to that described in Example 1 by reaction according to Friedel-Crafts from 3-methoxydiphenyl ether and p- (tert-butyl) -benzoyl chloride is 2-hydroxy-4 phenoxy-4 '- (tert-butyl) -benzophenone in the form of colorless crystals that melt at 88-90 °.

Example 4 Obtained in a manner analogous to that described in Example 1 by reaction according to Friedel-Crafts from 4- (tert. Butyl) -3'-methoxy-diphenyl ether and p- (tert-butyl) -benzoyl chloride is 2-hydroxy-4- (p-tert-butyl-phenoxy) -4'-tert-butyl-benzophenone in the form of colorless crystals melting at 134-136 °.

Example 5 46 parts of 3-hydroxy-4'-methyl-diphenyl ether and 30 parts Potassium iodide is dissolved in 220 parts of 2.5 N sodium hydroxide solution. The solution is then stirred and at about 800, dropwise with 32.7 parts of benzotrichloride offset.

After adding the latter, the dark mixture becomes 27 parts 5 N NaOH solution was added and the holes were briefly refluxed. The mixture is cooled acidified with hydrochloric acid and extracted with toluene. The toluene phase then becomes neutral washed, on that Solvent distilled off, the. Residue dissolved in chlorobenzene and filtered through aluminum oxide Petrol (bp 100-120 °) crystallizes, gives colorless needles of F: 82-850.

The new compound is 2-hydroxy-4-p-cresoxy-benzophenone, which also according to Friedel-Crafts (see. Process in Example 1) from 3-methoxy-4'-methyl-diphenyl ether and benzoyl chloride can be produced.

Example 6 16.9 parts of 3- (p-chloro-benzoyloxy) -4'-methyl-diphenyl ether are stirred in 14 parts of 1,2,4-trichlorobenzene at 1400 and within a half 8 parts of anhydrous powdered aluminum chloride were added up to one hour.

After half an hour the temperature is slowly increased to 2000. After stirring for 2 hours at this temperature, the mixture is cooled and brought to a Poured mixture of 24 parts of concentrated hydrochloric acid and 100 parts of ice.

The precipitated black mass is dissolved in 90 parts of toluene at 600, separated from the aqueous layer and washed neutral with water. When evaporating one obtains crude 2-hydroxy-4- (p-cresoxy) -4'-chlorobenzophenone, which after dissolving in hot ethanol containing a little dioxane and decolorization with activated charcoal on cooling Obtained in the form of colorless, needle-shaped crystals melting at 166/69 ° will.

The constitutional formulas of those described in Examples 1 to 6 above Compounds and their absorption maxima (2 max) are listed in Table 1 below.

Table 1 Example. Position and type of substituents # max in ethanol No. th in the above formula n 1 no substituent 320-330 2 4t-chlorine 315-332 3 4'-tert-butyl 322-333 4 4 ', 4 "-di-tert-butyl 315-330 5 4 "- methyl 315-330 6 4'-chloro-4 "-methyl 320-330 Examples 7 to 33 listed in Table 2 below are also obtained in a manner analogous to the compounds of Examples 1 to 6.

Table 2 E.g. position and type of substituents # max. In ethanol No. th in the above formula 7 4 "-n-butyl 315-330 8 4 "- n-nonyl 315-330 9 3 "-bromine 320-332 10 41-n-butoxy 322-335 11 41-n-octyloxy 322-335 12 4'-n-Dodecyloxy 322-335 13 3'-n-Butoxy 318-332 14 3'-n-octyloxy 318-332 15 3'-n -dodecyloxy 3180-332 16 3'-methyl-4 "-n-butyl 315-330 17 4'-n-Butoxy-4 "-methyl 320-335 18 4'-n-Octyloxy-4 "-methyl 320-335 19 4'-n-Dodecyloxy-4 "-methyl 320-335 Example position with type of substituents max. In ethanol No. th in the above formula nm 20 4'-n-Butoxy-3 "-methyl 325-340 21 4'-n-Octyloxy-3 "-methyl 325-340 22 4 ', 4 "-di-n -butoxy 320-335 23 4 ', 4 "-di-n-octyloxy 320-335 24 4 ', 4'1-di-n-dodecyl 320-335 25 3'-methyl-4 "-n-butoxy 315-332 26 3'-methyl-4 "-n-octyloxy 315-332 27 3'-methyl-4 "-n-dodecyl 315-332 28 4'-tert -butyl-3 ", 4" -dimethyl 315-330 29 4'-iso-nonyloxy-2 ", 4", 6 "-tri- 320-336 methyl 30 4'-tert-octyl-2 ", 6" -dimethyl-317-332 4 "-tert-butyl 31 3 ', 4'-dimethyl-4 "-n-nonyl 315-330 32 3 ', 4'-Di-chloro-4 "-tert.butyl 318-332 33 3 ', 4'-di-chloro-4 "-bromo 318-334 Examples of use A. Polypropylene is mixed homogeneously at 1800 with 0.5 of the compound described in Example 5 and then pressed to form sheets 0.3 mm thick. Panels are also made from the same polypropylene without adding any additives beforehand. The panels are tested for their lightfastness in a climate test using the De La nue method. The test is carried out at 40 °, at 75% relative humidity, with strong air renewal, with 16 sunlamps and 16 blacklamps from Philips. After exposure for 100 hours, the plates made of polypropylene without any additive show hairline cracks and are brittle. The plates which contain the compound according to the invention are still unchanged after exposure for 700 hours.

3. Panels made of polyvinyl chloride are prepared analogously as described above under A here, which 0.5. X of one of the compounds described in Examples 1 to 6 contain. After exposure for 1200 hours, these plates are still unchanged, while polyvinyl chloride plates containing no additive already after exposure are brown and cracked for 250 hours.

Claims (1)

P a t e n t a n s p r ü c h e 1. Process for the preparation of new 2-hydroxy-benzophenone compounds of the formula wherein the benzene nuclei A and B can be substituted, characterized in that in a compound of the formula wherein R denotes an alkyl radical, the radical R is replaced by hydrogen by treatment with acids, or that a compound of the formula One does not use the rest of the formula acylated donating compound or that one is a compound of the formula surrounded. II. The compounds of formula (1). III. Use of compounds of the formula (I) for stabilization of organic materials. lv. Organic materials that act as stabilizers compounds of formula (I) included. V. Organic materials that act as stabilizers compounds of formula (1), as well as other stabilizers and costabilizers against the action Contains nitrogen, heat and light.