BE598331A - - Google Patents

Description

       

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  "Oxidation of Organic Compounds."
The present invention relates to a new technique for selectively increasing the functionality of organic compounds which contain one or more functional groups especially when such buttocks are sensitive to oxygen.



   The present invention relates in particular to a new process in which the functionality of an or-

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   C2 to C30 strength containing at least one functional group is increased by reacting the compounds with molecular oxygen in the presence of a boric acid compound.



   The term "boric acid compound" is used herein to denote boric acid itself, namely H3BO3, and boron-containing compounds, which generate boric acid on contact with it. water, for example boric oxide, namely B2O3, borate esters, such as trimethyl, triethyl, tributyl boretes, etc., alkylboric acids, such as R2BOH (borinic acids) and RB (boronic acids ), in which R is an alkyl radical, preferably a C3 to C8 alkyl radical, and the esters of boronic and borinic acids with C1 to C4 alcohols. Among these compounds, tertiary borates, such as tertiary triamyl borate, more particularly tertiary trihutyl borate, are especially preferred.



  For an explanation of the properties. of the cited compounds of boric acid, reference may be made to "The Chemistry of Organometallic Compounts", Rochow, Hurd & Lewis, 1957, John Wiley and Sons, New York & London, pages 127-129.



   An object of the present invention is to provide a simple technique for the introduction of oxygen into the molecular structure of an organic compound containing at least one CH2 group and one or more functional groups, without seriously affecting the nature or decreasing. the number of functional groups already existing in such compounds.



   In a preferred embodiment of the present invention one or more additional hydroxyl groups are introduced into a substituted hydrocarbon which contains one or more existing hydroxyl groups, for example alcohols, glycols. and phenols.



   In another preferred embodiment, one or more hydroxyl groups are introduced into the olefins,

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 for example C3 to C12 monoolefins, such as prupylene, 2-methyl-1-butene, 2-methyl-2-pentene, cyclohexene, eptene, cyclododecene, etc.



   In general, the higher molecular weight olefins are less desirable feedstocks than the C3-C6 range olefins because the higher olefins are subject to reactions, such as fragmentation. The C2 olefins can also be oxidized according to the present invention separately or in admixture with other olefins, for example propylene and butenes.



   In another embodiment of the present invention, one or more hydroxyl groups are introduced into a C5-C12 unconjugated diolefin or polyolefin, for example 1,5-hexadiene, 2-methyl pentadiene-1,4 , vinyl cyolohexene, cyclo-octadiene and cyclododecatriene.



   In another embodiment of the present invention, one or more hydroxyl groups are introduced into carboxylic acids or esters thereof, for example C8-C18 alkanoic acids, such as octanoid acid. , lauric acid, stearic acid and other acids derived from animal and vegetable fats and oils, caproic acid, alkylated aromatic derivatives, such as the methyl ester of p-toluic acid and acids derived from petroleum, such as naphthenic acids, as well as polybasic acids, in particular dicarboxylic acids, such as glutaric acid, and their esters.



   In ordinary liquid phase oxidation of organic compounds which contain functional groups, such as the olefinic carbon-to-carbon double bond or oxygen-containing substituents, such as -OH, C-O, -COOH. and -COOR, etc., many side reactions ordinarily develop creating soil of various oxide products.

   Most often, the point of attachment of incoming oxygen occurs on or near the most sensitive functional groups,

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 resulting in destruction of the olefin double bond or the oxygen-containing substituent. Thus, for example, primary alcohols are oxidized to the corresponding aldehydes and acids, while secondary alcohols are oxidized to the corresponding ketones, if the initial carbon skeleton is to be preserved. A more vigorous oxidation of alcohols brings about a fragmentation of the initial carbon skeleton. In the liquid phase oxidation of the olefin, addition to the double bond or cleavage of the molecule can result as disadvantageous side reactions.

   However, various other side reactions also occur which reduce the yield of the desired product and complicate separation problems.



   It has now been discovered that organic compounds containing such functional groups, especially oxidation sensitive groups as described, can be selectively oxidized to introduce additional functional groups without substantially disturbing the basic structure. feed material, by reacting such organic compounds with molecular oxygen in the presence of the aforementioned boron compounds.



   The oxygen can be introduced in its undiluted form or it can be diluted with an inert gas, such as oxygen. For example, air can serve as an oxidizer or an oxygen-nitrogen mixture containing less oxygen than the amount normally found in air can be used. Other inert gases can be substituted for nitrogen. In a preferred embodiment, the oxidizing gas contains 3 to 5% oxygen and 97 to 94% by volume nitrogen or other inert gases.



   The amount of boric acid employed in this process can vary somewhat, depending on the feedstock and the desired end product. In general, the amount of boric ozide employed should be in excess of the amount which would be soechi-

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 metrically equivalent to the number of hydroxyl groups to be introduced.

   As in the preferred embodiment of the invention, it is generally desirable to perform only a partial conversion in a once-through operation (although a recycle or multi-phase operation is within the scope. of the invention), the amount of boric acid added to a reaction mixture in such an operation will generally be less than the stoichiometric requirements for a conversion of 100. Thus, the amount of H3BO5 employed for the oxida- - The proportion of an olefin or carboxylic acid, for example, should preferably be on the order of about 0.05 to 0.25 moles of H3BO3 per mole of olefin or carboxylic acid fed to the reactor.



  When using the other reported boron compounds, a chemically equivalent amount is used. It will be understood that 1 mole of H3B03, namely a tribasic acid, is considered to constitute three chemical equivalents. The same is true of the specified borate esters. In general, the present invention gives interesting results when using concentrations of H3BO3 which fall in the range of about 0.01 to 3, preferably 0.03 to 0.5 moles of H3BO3. per mole of organic feed, excluding diluent.



   The use of the higher portion of the range is especially desirable when relatively large amounts of inert diluent are employed. It is within the scope of the invention to carry out the oxidation reactions of organic compounds in the presence of an inert diluent or solvent, such as benzene, chlorobenzene, dichlorobenzene, b romobenzene, etc. Other inert diluents, such as carbon tetrachloride, can be employed. The presence of a diluent or solvent is especially preferred when oxidizing relatively low boiling point feeds, for example propylene and isobutylene.

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   Likewise, the temperature and pressure employed with this technique will vary somewhat with the particular reaction targeted. However, in general, the process can be carried out at temperatures in the range of 100 to 300 C, preferably 1500 to.
185 C. and at pressures ranging from approximately atmospheric pressure to pressures ranging from. atmospheric pressure rises or less to 200 atmospheres or more, preferably 50 atmospheres.



   The oxidation of organic compounds containing functional groups in the presence of boric acid (or other boron compounds) / usually oxygen in organic compounds in the form of a borate ester of the alcohol, we first thought that the increased selectivity observed may result from the introduction of an OH group into the organic molecule, and immediate esterification thereafter, to avoid another reaction.



   This simple explanation is not satisfactory since the use of acetic or phosphoric acid instead of boric acid does not give the selective process described in the present invention.



   The borate ester of the produced alcohol (glycol, etc.) can be con erted to the corresponding alcohol (glycol, etc.) by reaction with water or, preferably, with a lower molecular alcohol, for example. a C1-C3 alcohol, preferably methanol. This ester exchange reaction, especially when methanol is used, is a preferred method of recovering boric acid or its derivative from the reaction mixture. When the ester exchange reaction with methanol is used, trimethyl borate can be recovered as an azeotrope, boiling 54.8 C (769 mm Hg) and containing 26.1% by weight of methanol.



   The invention may be better understood from the following description of some particular embodiments.



   Synthesis of polyhydroxy compounds
The need for a simplified process for the production of diols, trols and other polyhydroxy compounds has become more

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 pressing due to the expansion of the use of such chemicals in the manufacture of plasticizers, agricultural chemicals, polyesters as well as other polymers or resins, drugs, agents. surfactants, chemical intermediates, etc.



   According to prior art methods, glycols can be obtained by hydrolysis of the corresponding oxide, hydrolysis of hydrochlorins, direct hydroxylation of an olefin with a peroxide and, on a laboratory scale, reaction of olefins with. of KMnO4. Each of these processes has particular advantages but also has disadvantages, such as expensive raw materials, multi-phase operations, complexity of the reactions involved, etc.



   By the process of the present invention, glycols can be prepared by the direct oxidation of C2 and higher monovalent alcohols and / or their borate esters. High glycol selectivity can be achieved by first esterifying alcohol, such as propanol, with boric acid or B2O3 or by transesterification with methyl borate.



  Air is passed through the resulting ester mixture in the presence of an additional sufficient amount of boric acid or one or more of the boron compounds mentioned, in an amount at least chemically equivalent to roups of. additional hydroxyl to be formed, followed by reaction of the resulting mixture with water or, preferably, methanol or other suitable alcohol to recover the desired glycols. Or, glycols can also be produced by simultaneous introduction of both oxygen and a boric acid compound to the alcohol feedstock.

   The selectivity to glycols is promoted by controlling the rate of oxidation so as not to allow it to exceed the rate of reaction of the boron compounds with the reaction mixture. When preparing a glycol starting from a monoalcohol, it is preferred to esterify the al-

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 cool to form the borate ester and then use about 0.06 to 0.25 additional moles of H3BO3 (or equivalent amounts of other boron compounds mentioned) in the reaction, per mole of alcohol.

   This corresponds to the use of about 0.4 to 0.6 moles of H3Bo3 per mole of alcohol. Glycols which can be prepared in this way are propaned iol (from propanol), butanediol (from from butanol), hexanediol (from hexanol), etc. Branched chain alcohols and straight chain fatty alcohols, such as those containing 8 to 18 carbon atoms, are especially useful feedstocks for the manufacture of higher glycols. The conversion of ethanol to ethylene glycol by this process is a particularly interesting embodiment of the present invention.



   According to the present technique, it is also possible to prepare polyols, for example glycerol, from propanol and / or its borate ester.



   In one embodiment of the present invention, glycols are prepared first by absorbing an olefinic feedstock in sulfuric acid under pressure to form an extract containing acid sulfate. alkyl, then hydrolysis of such an extract to liberate the corresponding alcohol, for example isopropanol, and air oxidation of such an alcohol in the presence of boric acid, according to the present invention.



   Other polyhydroxy compounds can be prepared by this general technique, employing as an organic feedstock compounds which have one or more hydroxyl growths in their molecular structure. Thus, xylylene glycol (benzenedi-carbinol) can be formed starting from the corresponding tolylcarbinol (methylbenzyl alcohol), and other aromatic polycarbinols, starting from the corresponding aromatic alkyl alcohols. Likewise alkylated phenols can be converted to phenolic alcohols and glycols.

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  Synthesis of unsaturated alcohols, aldehydes and ketones
By oxidizing an olefin with air, in liquid phase, in the presence of boric acid or a boron compound mentioned above, the reaction can be made selective towards the borate ester of the unsaturated alcohol. corresponding. Subsequent hydrolysis will give the unsaturated alcohol or transesterification with another acid will give an unsaturated ester of the desired composition.



   Unsaturated alcohols which can be prepared according to the present. process are 2-methyl-2-pentene-4-cl from 2-methyl-2-pentene or propylene by dimerization, orotyl alcohol from 2-butene, methylallyl aloool from from isobutene, and allyl alcohol from propylene, cyolohexenol from cyolohexene, etc.



   The unsaturated unsaturated alcohols of the preceding examples can be converted to unsaturated aldehydes and ketones by selective oxidation or dehydrogenation. Thus, mesityl oxide can be formed by starting from 2-methyl-2-pentene via oxidation in the presence of boric acid to form the borate, and this can be converted into unsaturated ketone. Likewise, unsaturated alcohols can be converted into an acidic solution to effect hydration into glycols or polyols; for example hydrolysis in an acid solution of the borate ester obtained in the oxidation of 2-methyl-2-pentene will give the glycol. Peroxidation will give the triol.



   The invention also relates in particular to a new process for the preparation of an unsaturated alicyclic alcohol by liquid phase oxidation of an alicyclic olefin in the presence of boric acid or of a boric acid compound.



   Unsaturated cyclic alcohols are useful for many chemical applications. For example, they find use in resin compositions and can be esterified with a carboxylic acid to give ples-

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 Valuable tifiers which, before or after mixing, can be epoxy or subjected to cross-linkage reactions, These alcohols can also be converted into glycols, triols and diolefins, or treated with a caustic material, for example KOH, to give advantageous acids or derivatives.



   Heretofore attempts to oxidize alicyclic olefins with molecular oxygen, for example afr, have yielded a product mainly comprising epoxides and high molecular weight condensation products. Reference may be made, for example, to British Patent No. 729,983.



   Although this method can be advantageously employed with any alicyolic olefin, it is particularly suitable with compounds having a large number of carbon atoms in the cyclic portion of the molecule, for example with cyolododecene, since the method allows the conversion. in alcohol as the main product with little or no loss in nucleus cleavage. Other suitable feedstocks are C5 to C20 alicyclic olefins and alkyl substituted cyclic olefins, in which one or more hydrogen atoms attached to a ring carbon are replaced by a C1-C4 alkyl radical, for example methylcyclohexene, etc.



  Synthesis of hydroxy acids
Oxidation in air in the liquid phase of stearic acid or an ester thereof in the presence of boric acid or a derivative thereof introduces one or more hydroxyl groups along chain. Other acids, especially those of the C10-C30 range, when oxidized under the conditions of the present invention, become suitable for use in alkyd resins, plasticizers, and the like. Branched acids, such as those derived from olefins, can be oxidized by the process of the present invention.

   Acids of this type are those prepared by the well known Oxo process, in which olefins are reacted with hydrogen and carbon monoxide at a temperature of the order of about 70 to 200 ° C. under a pressure between 150 and 300 atmospheres

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 in the presence of a carbonylation catalyst containing or a metal, for example acetate / cobalt oleate, to convert the olefin to an aldehyde which in turn is oxidized to produce the corresponding acid.

   Suitable acids also include those prepared by reacting an olefin with carbon monoxide under similar pressures in the presence of an acid catalyst, eg BP3.2H20, H3PO4-BF3-.
H2O, concentrated H2SO4 and H2SO4-BF3-HZO at lower temperatures eg 25-40 C, etc. In the latter process, water may be present in the reaction zone, or the reaction product may be hydrolyzed subsequently.



   Synthesis of unsaturated nitriles
Starting again from an olefinic feedstock, the general technique of the invention can be modified to produce unsaturated nitriles by first oxidizing the olefin in the presence of boric acid (or others. boron compounds), and then contacting the resulting borate ester or its alcohol derivative with a mixture of ammonia and air.



  An example of this synthesis is the oxidation of isobutylene, in the presence of boric acid, to methalyl alcohol borate. The oxidation product can then be reacted at elevated temperatures with ammonia and air in the presence of a catalyst, such as a catalyst containing molybdenum oxide, by example of bismuth phosphomolybdate, to produce methacrylonitrile.



   Another example of this embodiment involves the production of acrylonitrile using a propylene feedstock.



   Although it is often preferred not to use a catalyst, oxidation catalysts which include compounds of cobalt, manganese, and similar metals, can be advantageously used in certain embodiments. However, such catalysts sometimes tend to reduce the

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 selectivity towards hydroxy compounds: yl4s. An especially effective embodiment of the present invention for certain feedstocks is the oxidation in the presence of boric acid and a bromide, such as ammonium bromide, of HBr. , MnBr ?, isopropyl bromide, etc.

   Although less advantageous, the corresponding chlorides can be used instead of or instead of the bromides. A bromide concentration of 0.1-10% by weight (calculated for ammonium bromide and based on organic feedstock) can be used, although preferred concentrations, when using. additions of bromide, are 0.5 to 2% by weight. Other additives which may be present advantageously during the oxidation in the presence of boric acid are acids, such as acetic acid. With some feedstocks, there may be advantages to introducing small amounts of oxidation initiators, such as peroxides, hydroperoxides, detones, such as methyl ethyl ketone, and: 6 .



   The presence of boric acid is also beneficial during the air oxidation of ketones, nitriles and halogen derivatives of certain hydrocarbons.



   It has been found that when a borate ester of a tertiary alkanol, especially tertiary tributyl borate, is employed, the overall rate of reaction is dramatically increased.
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 Alkylertiary borates provide other advantages, as they are soluble in hydrocarbons and other organic compounds, a homogeneous reaction mixture results. They are less corrosive than boric acid.

   They have advantages over borate esters of lower molecular weight, due to their higher boiling points, 175 C and above, this
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 .... \., 1 ',; ,,, which allows the reaction to be carried out at atmospheric pressure-).> 1. ::'. .., '¯Â, r, z - .. ^. A: f..a "s, $ rn', ^ a. And '^' m; 'r,' - '' rt., ¯ '. n- ¯Î] ,,?, J, Ç "1 'rique.Plls are.superior than" to "at" summer "at"%' ôims molé "auhaix z, *, 14 .:" = .r.> c ± 1.;: '.. ei.r> ÀÉ% 6K' =, 1>; .. i "",> -'...,> '. <.

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 comparable, in that they are themselves more resistant to oxidation.



   The compound to be hydroxylated is mixed with 1-: tertiary borate with or without an inert diluent, so as to form a liquid reaction solution or mixture. The resulting mixture is maintained at a temperature on the order of about 100 to 300 ° C., preferably 130 to 180 ° C., while molecular oxygen is introduced into the mixture. The reaction can be carried out efficiently at pressures of the order of 1 to
50 atmospheres. An oxidation catalyst can be employed with the reaction mixture. The amount of tertiary borate employed is preferably in the range of about 0.01 to 1 or more, preferably 0.03 to 0.7 moles, of the borate per mole of organic reactant fed to the reactor.



   The reaction can be carried out in several phases. A single hydroxyl group can be introduced into an aliphatic or aromatic compound. In the presence of a tertiary borate under the reaction conditions used in the present process, the hydroxy compound is transesterified to form a bora ester of the oxidized feedstock. This ester can then be oxidized before or after separation of the reaction mixture, in order to introduce additional hydroxyl groups in the presence of additional tertiary borate, these groups being in turn blocked starting from an additional oxidation.



   The compounds which can be advantageously hydrolyzed in the presence of tertiary borates are, by way of example, cyclic, saturated and unsaturated C2 to C30 aliphatic and acyclic hydrocarbons; alkylaryl and arylalkyl hydrocarbons, for example toluene, xylene, diisopropyl benzene, eto; high molecular weight hydrocarbon polymers, for example, polyethylene, polypropylene, butyl rubber, etc., and substituted hydrocarbons, such as C2 to C30 alcohols, .etc.

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   The present invention also relates to the preparation of aromatic alcohols, in particular to a process for the hydroxylation of the alkyl substituent of alkylaryl and arylalkyl hydrocarbons by oxidation of such compounds in the presence of an acid compound. boric.



   Aromatic alcohols and glycols find use as resin modifiers, as additives to lubricating oils, in the preparation of plasticizers, and as intermediates in the preparation of a large number of agricultural and agricultural chemicals. pharmaceutical products.



   The oxidation of alkyl aromatics in the liquid phase with molecular oxygen, eg air, ordinarily produces a series of products. Thus, in processes known from the prior art, oxidation proceeds through and beyond hydroxylation and results in the production of aromatic aldehydes, acids, etc. Reference may be made, for example, to US Pat. No. 2,653,165 and to British Pat. No. 623,836, etc.



   In accordance with the present invention, aromatic alcohols, for example monovalent, divalent and polyvalent aromatic alcohols, can be prepared by liquid phase air oxidation of alkyl aromatics in the presence of a boric acid compound.



   In the present process, an alkyl aromatic hydrocarbon, for example toluene, xylene, ethyl oenzene, diisopropyl benzene, durene, pseudocumene, etc., is mixed with a boric acid compound, with or without diluent, so as to form a liquid reaction solution or mixture. The resulting mixture is maintained at a temperature of the order of 1200 to 300 C, preferably 130 to 180 C, while molecular oxygen is introduced into the mixture. The process can be carried out effectively at pressures on the order of 1 to 50 atmospheres.

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  An oxidation catalyst can be employed with the reaction mixture, but the reaction can be carried out without using the catalyst.



  EXAMPLE 1
A monovalent C13 branched chain alcohol, prepared by the aforementioned Oxo process, is first esterified by mixing 1900 g of such alcohol with 185.5 g of H3B03 and about 1100 cm3 of heptane, and heating the resulting mixture for about 5 hours at reflux temperature, i.e. about 95-98 C.



  The solvent heptane and excess alcohol are removed by distillation leaving the borate ester as a residue. Of this residue, 507 g of ester are charged to a glass reaction vessel. About 26 g of H3BO3 are added to the ester. Air is then bubbled through the resulting mixture for 105 minutes.



  The oxidation is carried out at an average temperature of about 170 ° 0, the range being 160 and 175 C at atmospheric pressure. During the reaction, water is continuously removed by the exhaust gas. The total air introduced during the oxidation is 20 cubic feet measured at room temperature, ie about 25 ° C, and at atmospheric pressure. The progress of the reaction is followed by measuring the water removed with the exit gas.



   At the end of the oxidation, the reaction mixture is treated with methanol at reflux temperature, i.e. 1 about 60 - 65 C, thereby recovering the H3B03 as an overhead product as a mixture of methanol and of lower boiling point methyl borate. The residue is distilled at a pressure of 15 mm Hg to recover the glycol product, the unreacted alcohol and a higher molecular weight product.



   A previous residue analysis revealed that 15% by weight of the alcohol had been converted. In this converted amount the selectivity to glycol was 62.



   The same monovalent branched chain alcohol is oxidized under the same conditions as in the treatment described above.

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      before but without the use of H3BO3. The alcohol is treated with air for 106 minutes at an average temperature of about 170 ° 0, range 160 to 15 C, at atmospheric pressure. At the end of the oxidation, the product is distilled and analyzed. No glycol is found despite the fact that more of the alcohol is oxidized. Among the products found are esters, acids and compounds containing carbonyl. This shows the marked and surprising effect of H3BO3 on the selectivity to glycols when oxidizing alcohols.



    EXAMPLE 2
The process of the first treatment, of Example 1, is repeated except that a mixture of oxygen and nitrogen containing about 5% by volume of O 2 is used instead of air. The oxidation time is extended to about 5 hours. Higher selectivity to glycol occurs.



  EXAMPLE 3
The process of Example 1 is repeated except that the alcohol employed is a straight chain C18 monovalent alcohol.



  Analysis again reveals glycols in the product.



    EXAMPLE 4
The procedure of Example 3 is repeated except that a nitrogen stream containing about 10 to 12 volume% oxygen is employed as an oxidant. Glycols are recovered as a product.



    EXAMPLE 5
A glycol is again prepared in the presence of H3BO3 as in Example 1 but with the following changes in reactants and processes. The alcoholic diet used consists of normal propanol. A charge of 2000 g of propanol is esterified with 496 g of H3BO3. The resulting borate ester is separated from the reaction mixture by distillation and 750 g of the borate ester is transferred to

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 a reaction vessel. About 125 g of H3BO3 are added. A diluent, namely benzene, is also used.

   The oxidation is carried out at an average temperature of 165 ° C and a pressure, of about 10 to 12 atmospheres, using a mixture of air and, nitrogen, containing about 4% by volume of oxygen. Water is removed during the reaction period, and benzene, together with unconverted reactants and products carried off by the exit gas, are recycled to the reaction. After 5 hours of reaction, the product is cooled, treated with methanol, and the trimethyl borate and methenol are removed. Distillation and analysis of the product indicate the presence of propanediol.



    EXAMPLE
3X & * LQ The procedure of Example 1 is repeated - except that methyl borate is used instead of H3BO3 to convert the C12 alcohol to the borate ester. A charge of 500 g of this ester is charged to a reactor and 55 g of methyl borate are added. The oxidation is carried out at an average temperature of about 170 ° C and a pressure of about 15 atmospheres. Product analysis revealed even higher selectivity to glycol.



   EXAMPLE 7
An olefin, 2-methyl-2-pentene, is introduced into a reactor. About 50 g of H3BO3 are added. The oxidation is carried out at 170-180 C with a mixture of nitrogen and air, containing about 4% by volume of oxygen, at a pressure of about 8 to 10 atmospheres. Methanol is added to the product and the resulting mixture is distilled off. Analysis shows that the olefin feed is converted to unsaturated alcohol with high selectivity.
The unsaturated alcohols recovered can be esterified with acetic acid in the presence of toluenesulfonic acid. The resulting esters can then be reacted with hydrogen peroxide and the resulting hydroxy epoxides are

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 hydrogenated to the corresponding glycols.

   Or, the hydroxy epoxides can be saponified to give triols.



  EXAMPLE 8
The process of Example 2 is repeated except that the feed is stearic acid, C17H35COOH. The acid is first esterified with methanol to form methyl stearate. A 900 g charge of the ester, together with 30 g of H3B03, are reacted with a mixture of nitrogen and air, containing about 8% by volume. from O2 to 170 ° C. After the reaction, methanol is added to transesterify the hydroxy stearate ester of boric acid and the resulting products are distilled to remove excess methanol and methyl borate. Analysis of the residue revealed extensive conversion of stearic acid to hydroxy stearic acid methyl ester.



    EXAMPLE 9
The procedure of Example 1 is repeated except that 2-ethylhexanol is used as the feed. This is first esterified with boric acid. About 800 g of the resulting C8 borate ester are charged to the reactor with about 25 g of boric acid and about 0.5% by weight of ammonium bromide (based on the alcoholic feed) is supported. of nitrogen containing about 5% by volume of oxygen is used as an oxidant. The selectivity of the converted alcohol to glycol is about 65%.



  EXAMPLE 10
A charge of 65 g of the mixed isomers of xylene and 16 g of the tertiary tributyl borate (molar ratio 0.61 / 0.07) are heated to vigorous reflux (137-139 C) in the presence of 0.01% by weight. cobalt (as cobalt naphthenate. Air at a rate of 200 cm3 / minute is passed through the reaction mixture for 2 hours. The crude product is washed with dilute Na2CO3 solution, separated and washed. again

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 with water. Analysis of the mixture of product and unreacted xylene revealed a conversion of about 10% by weight of the xylene feed. The product has a 2: 1 ratio of methylbenzyl alcohols (tolyicarbinols) to aldehyde. Acids and phenol are not found in this product.



  EXAMPLE 11
Cyclododecane is used as the feedstock and tertiary t-ributyl borate is compared to boric acid. In each test, the molar ratio of the boron-containing compound to cyclododecane is 0.165 / 1. Air is used as the oxidant and is passed through the reaction mixture at an average rate of 2500-270 cc per minute. No catalyst is used.



   A comparison of the oxidation rates in the presence of the two boron-containing compounds is given in the following table.



   TABLE I Comparison of the oxidation rates of cyclododecane in the presence of boric acid and tertiary butyl borate
 EMI19.1
 
<tb> Oxidation <SEP> Duration, <SEP> Temperature, <SEP>% <SEP> of <SEP>% <SEP> of <SEP> selected
<tb>
<tb> hours <SEP> C <SEP> conversion <SEP> speed <SEP> to <SEP> alcohol
<tb>
<tb>
<tb>
<tb> Butyl <SEP> borate <SEP> <SEP> 2 <SEP> 155-160 <SEP> 20.6 <SEP> 77.5
<tb>
<tb>
<tb> tertiary
<tb>
<tb>
<tb>
<tb>
<tb> "<SEP> 2.08 <SEP> 155-160 <SEP> 22.2 <SEP> 77.5
<tb>
<tb>
<tb>
<tb>
<tb> Boric <SEP> <SEP> 5.25 <SEP> 160 <SEP> 27.2 <SEP> 81
<tb>
<tb>
<tb>
<tb> "<SEP> 6.75 <SEP> 160 <SEP> 21.4 <SEP> 83
<tb>
 
EXAMPLE 12
The process of Example 11 is repeated except that cyclooctene is used as the feedstock.

   Bu cyclooctenol is recovered as the main product. High molecular weight polymers resulting from the air oxidation of non-cyclic / saturated compounds are not found in measurable amounts.



  EXAMPLE 13
The process of Example 11 is repeated with normal heptane employed as the organic feedstock, with

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 tertiary trianyl borate. The oxidation product is analyzed and found to exhibit a high selectivity towards monovalent alcohol On * EXAMPLE 14
A monovalent C13 alcohol is esterified by mixing such an alcohol with H3BO3 and heptane, and heating the resulting mixture for about 5 hours at reflux temperature, i.e. at about 95 to 98 ° C. heptane solvent and excess alcohol are removed by distillation, leaving the bota ester as a residue.

   Of this residue, about 3 moles of the ester are char gelled in a glass reaction vessel, along with about 1 mole of tertiary butyl borate, and air is bubbled through the mixture. reaction for about 2 hours at a temperature of about 170 C.



   At the end of the oxidation, the reaction mixture is treated with methanol at reflux temperature, ie about 60 to 65 ° C, to recover a mixture of methanol and methyl borate. The residue is distilled at a pressure of about 15 mm Hg to recover a C13 'glycol from the alcohol having no
 EMI20.1
 unreacted and a higher molecular weight product.



   Analysis of the residue reveals that about 35% by weight of the alcohol has been conerted. In the amount converted, the selectivity to glycol is about 60%.



   EXAMPLE L5
Cyclododecane is oxidized in the presence of normal tributyl borate and also in the presence of tertiary tributyl borate. The oxidation is carried out at a temperature of about 160 C. The charge of oyclododecane of the reaction is
0.3 mole in each operation. The amount of the boron-containing compound charged to the reaction is 0.05 moles for the treatment with normal tributyl borate and for the treatment with tertiary tributyl borata. Air circulation to the mixture
 EMI20.2
 't .. ... r J ..>: <; - ¯, i

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 Reaction age is 270 cm3 per minute for each operation.



  Air circulation is terminated in each operation after
3 and a half hours. The crude product is hydrolyzed with H2O at about 90 ° C. After cooling, diethyl ether is added and the aqueous layer is separated. The ether layer is washed once more with water, dried and the ether is removed by separation at about 25 ° C. The product is analyzed. The results obtained are given in Table II.



   TABLE II Comparison of the oxidation of cyolododecane in the presence of normal tributyl borate and tertiary tributyl borate% of conversion% of selectivity to cvclododecanol Normal tributyl borate 37 42 Tertiary tributyl borate 46.4 62
On analysis of the product, it was also found that when using tertiary tributyl borate, a quantitative recovery of tertiary butyl alcohol was achieved, while the hydrolysis of the product, when tertiary borate was achieved. Normal tri-butyl is used, gives normal butyl alcohol soiled with butyaldehyde.



  EXAMPLE 16
A 45 gram charge of cyclododecene (0.27 mole) is heated to 155-165 ° C and air is passed through this charge at the rate of 100-200 cc per minute. After a short priming period, the absorption of oxygen is observed and then 2.5 g of H3BO3 (0.041 mol) are added. After 3 and a half hours, the air circulation is stopped and the mixture is mixed. of crude oxidation is cooled and dissolved in 300 ml of ether. The resulting solution is raised with a saturated solution of NaHCO3, then
 EMI21.1
 a, solution of NS2CO3. to.- bzz, and finally with water. After drying, the ether is removed by evaporation. The product is dis-
 EMI21.2
 - 'l ... 1 ty ..' u

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 tilled to remove unreacted cyclododecene.

   The overall conversion is around 36%. The main product is cyclododecenol with a selectivity of about 50%. The alcohol is mainly 3-hydroxy cyclododecene. The other product is cyclododecene oxide with a selectivity of 40%. The rest of the material is a ketone.



    EXAMPLE 17
The procedure of Example 16 was repeated in the absence of boric acid, using cyclooctene as the olefinic feedstock, and the selectivity of the product was found to be as follows: Epoxide 55% Alcohol and ketone 15% Other products, in particular suberic acid and its esters, together with unidentifiable high molecular weight condensation products 35% EXAMPLE 18
Example 16 is repeated / and trimethyl borate is used instead of H3BO3. A pressure of 10 atmospheres and a temperature of 16000 are used. Again, high selectivity to cyclododecenol was achieved with no evidence of ring cleavage or significant cracking.



  EXAMPLE 19
Example 16 is repeated except that cycloctene is used as the olefinic feed and cyclooctenol is starchy as the product. The selectivity is around 50%.



    EXAMPLE 20
Example 16 is repeated, except as regards the following: boric oxide is used instead of boric acid, a mixture of oxygen and nitrogen, containing about 8% by volume of air, is used as an oxidizer. About 0.01% by weight of colbalt naphthenate (based on the olefin) is added to the reaction mixture. The olefinic feed is cyclododecene. The selection

 <Desc / Clms Page number 23>

 activity is approximately the same as in Example 1.



   EXAMPLE 21
Example 16 is repeated except that no boric acid or a compound thereof is used. The selectivity towards cyclododecene is extremely low.



     EXAMPLE 22
A charge of 65 grams of mixed xylenes, namely o-, m-, and p-xylene, and 16 grams of tertiary ributyl borate (molar ratio 0.61 / 0.07) are heated to a average temperature of about 138 ° C. in the presence of 0.01% by weight of cobalt (in the form of cobalt naphthenate). Air at a rate of 200 cc per minute is passed through the reaction mixture for 2 hours. The crude product is washed with dilute Na2CO3 solution, separated and washed again with esu. Analysis of the mixture of product and unreacted xylene revealed a conversion of about 10% by weight of the xylene feed. The product has a 2: 1 ratio of methylbenzyl alcohols (tolylcarbins) to aldehyde. Acids and phenols are not found in the product.



  EXAMPLE 23
Tolyl carbinol is heated with tri-methyl borate to an average temperature of about 160 ° C. at a pressure of about 10 atmospheres in the presence of 0.01 by weight of cobalt naphthenate. Water is passed through the mixture as in Example 1. The oxidation product is hydrolyzed, separated and a xylene diol is recovered.



    EXAMPLE 24
A charge of 624 g of diisopropyl benzene (4 moles) and 31 g of H3BO3 (0.5 mole) are heated at 160-175 C for four and a quarter hours. Air is passed through the reaction mixture during this period. The total amount of air allowed is 20.4 cubic feet. The reaction mixture is then

 <Desc / Clms Page number 24>

      heated at reflux for 2.5 hours with 1500 cc of methanol. Methanol and methyl borate are removed by distillation, and the product is distilled. Analysis of the product revealed the presence of hydroxidation in the side chain.



    EXAMPLE 25
The procedure of Example 22 was repeated except that p-xylene was used as the organic feedstock and the reaction was carried out at 145 ° C. Analysis of the hydrolyzed product revealed high selectivity to alcohols. Acids and phenols were not found in the reaction mixture.



  EXAMPLE 26
The process of Example 22 is repeated except that the tertiary tributyl borate is omitted from the reaction zone. Analysis of the hydrolyzed product revealed the presence of significant amounts of p-toluic acid.



  EXAMPLE 27
The process of Example 22 is repeated, except that the pseudocumene is emolished instead of the mixed xylenes. Analysis of the hydrolyzed product reveals that alcohols are the main product.



   The reaction can also be applied to nephthens, such as cyclopentane, cyclohexane and cycloheptane unsubstituted or substituted with methyl or ethyl, as shown by the following example.



  EXAMPLE 28
A stainless steel reaction vessel is charged with 300 g of a paraffinic feed containing about 85% cyclohexane. 77 g of boric anhydride and 3 g of cobalt naphthenate are added. The reactor is pressurized to about 200 pounds per square inch with air and the mixture is heated to about 375 F. Then, air is passed through the reaction mixture for about. 1 hour with agitation. At the end of this period, the air circulation is stopped

 <Desc / Clms Page number 25>

 r to the reactor and a sufficient amount of water is added to hydrolyze the boric acid ester complexes.

   The oily phase is recovered and the cyclohexanol and cyclohexanone are separated therefrom by any suitable technique, such as distillation (eg, cyclohexanol and cyclohexanone in aqueous phase can be recovered by distillation or liquid-liquid extraction. ).



   Alternatively, the reactor is cooled to room temperature and the borate ester is recovered by distillation. The ester (which melts above room temperature and boils at about 330 ° C) is heated to a temperature of about 100 ° C and a sufficient amount of water is added to hydrolyze virtually everything. ester. The boric acid which is formed enters the aqueous phase and the oyolohexyl alcohol is recovered by liquid-liquid separation.



   The reaction is also applicable to C8 to C20 cyoloparaffins of the cyclo-octane and cyclododecane type, as shown by the following example.



  EXAMPLE 29
Cyclododecane is reacted at atmospheric pressure with air (21% oxygen) supplied at a rate of about 2.1 cubic feet per mole of cyclododecane per hour in a laboratory reactor, stirred and of the discontinuous type, under the conditions described below: Boric acid,% by weight 0 Temperature, C 160 160 Conversion, moles% 31 21 Selectivity, moles%
Alcohol 30 83
Ketone 20 9
Alcohol + ctone 50 92

 <Desc / Clms Page number 26>

 
The alcohols and ketones are recovered from the reaction products as follows. The crude reaction mixture is dissolved in diethyl ether and is then washed twice with 6.5% by weight sodium bicarbonate to hydrolyze the borate esters.

   The mixture is then washed two more times with 2% by weight sodium carbonate to remove the acids, then washed three more times with water. The mixture is then dried over anhydrous magnesium sulfate and, after filtration, the ether is removed in a rotary evaporator. The combined aqueous washes are then acidified to isolate any additional aids, if any. The quantities of the products obtained are then determined by standard analytical methods. These results show that boric acid greatly improves the selectivity of the desired products.



   The term "air oxidation" is used herein to denote an oxidation process in which the source of oxygen is a gas consisting essentially of a mixture of an inert gas and molecular oxygen.



   The term "inert gas" is used herein to denote a gas which does not react with or catalyzes reactions between organic compounds and boric acid compounds and is inert to oxidation at the reaction conditions given herein.



   All percentages herein are percentages by weight, unless otherwise noted.



   It will be understood that the boric acid compound should) be present in an easily reactive form. Thus, it can be present as a substance which is a liquid under reaction conditions, a finely divided solid, or in solution. Molten boric acid compounds, eg, molten boric oxide, are unsatisfactory.

** ATTENTION ** end of DESC field can contain start of CLMS **.


    

Claims (1)

CLAIMS 1. A process for introducing oxygen into a component containing EMI26.1 'se oranique C2 to C; o, 1Xxixxx / at least a functional troop, <Desc / Clms Page number 27> which comprises contacting this organic compound with molecular oxygen in the presence of a boric acid compound under oxidation reaction conditions. 2. A process according to claim 1, wherein the boric acid compound is H3BO3. 3. A process according to claim 1, wherein the boric acid compound is trimethyl borate. 4. A process according to claim 1, characterized in that an organic compound selected from the group consisting of olefins and compounds is used as the feed. consisting of carbon, hydrogen and oxygen, contacting this organic compound with a molar oxygen-containing gas in the presence of an inert diluent and about 0.01 to 3 moles of a compound of. boric acid per mole of the organic compound at a temperature of the order of 100 to 300 C. 5. A process according to claim 4, wherein the organic compound is a monovalent aliphatic alcohol. 6. A process according to claim 4, wherein the organic compound is an aliphatic carboxylic acid. 7. A process according to claim 4, characterized in that 0.03 to 0.5 mol of a boric acid compound and an oxidation catalyst are used at a temperature of the order of 150 to. 185 C. 8. A process according to claim 7, wherein the oxidation catalyst is ammonium bromide. 9. A process according to any one of claims 4 to 7, wherein the inert diluent is a compound from the group consisting of benzene, chlorobenzene, bromobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene. , 1,4-dichlorobenzene, 1,2-dibromobenzene, 1,3-dibromobenzene, and 1,4-dibromobenzene. 10. A process according to claim 1 which comprises mixing boric acid with a monovalent C2 to C30 alcohol and heating said acid and alcohol until a <Desc / Clms Page number 28> borate ester of the alcohol is formed, contacting the ester with molecular oxygen in the presence of an inert diluent and. of about 0.05 to 0.5 moles of boric acid per mole of ester at a temperature of the order of 1000 to 250 C, cooling the resulting mixture to a temperature below the boiling point of methanol, adding methanol to this mixture, fractionating the mixture containing methanol and removing a fraction comprising methanol and boiling above about 65 C leaving a residue containing a C2 to glycol. C30, and separating this glucol from the residue. 11. A process according to claim 1, characterized in that a borate ester of a tertiary alcohol, preferably tertiary tributyl borate, is employed as the boric acid compound and the reaction is carried out. at a temperature of the order of 100 to 300 C. 12. A process according to claim 11, characterized in that the feed is an aliphatic or cyclic, saturated unsaturated hydrocarbon, or a monovalent alcohol which is converted by the reaction to a glycol. 13. A process according to claim 1, characterized in that an alicyclic olefin is used as the organic compound, for example cyclododecene, and a temperature in the range of 100 to 250 is used. vs. 14. A process according to claim 1, characterized in that an alkyl aromatic compound is used as the organic compound and a temperature of the order of 120 to 300 C is employed to produce an aromatic alcohol. 15. A process according to claim 1, characterized in that a naphthene containing 5 to 7 carbon atoms in the ring is used as the organic compound and a cyclonaphthyl alcohol and / or a ketone is recovered. 16. A method according to claim 1, characterized by <Desc / Clms Page number 29> ized in that a C8 to C20 cycloparaffin is used as an organic compound and a cyclic alcohol and / or a ketone is recovered. 17. The proceeds, as described above.