Olefins carboxylic acid addition

Tables 4 and 5 include several electron adducts of aromatic and olefinic carboxylic acids. The dissociation constants of these radicals are generally much higher than those of the parent acids because of the additional charge. It appears that one should not compare the value of 12-0 for the electron adduct (C6H5C02H) with pK = 4-2 for C6HsC02H. Instead, a comparison of the first pA = 5 3 for the conjugate acid of the electron adduct (C6HsC02H2)" seems more suitable. Similarly pK for the conjugate acid of the electron adduct of the C6HsC(OH)OCH3 (5-5) is comparable to that of the acid or...

The boric and sulfuric acids are recycled to a HBF solution by reaction with CaF2. As a strong acid, fluoroboric acid is frequently used as an acid catalyst, eg, in synthesizing mixed polyol esters (29). This process provides an inexpensive route to confectioner s hard-butter compositions which are substitutes for cocoa butter in chocolate candies (see Chocolate and cocoa). Epichlorohydrin is polymerized in the presence of HBF for eventual conversion to polyglycidyl ethers (30) (see Chlorohydrins). A more concentrated solution, 61—71% HBF, catalyzes the addition of CO and water to olefins under pressure to form neo acids (31) (see Carboxylic acids). 

Interest in synthetic naphthenic acid has grown as the supply of natural product has fluctuated. Oxidation of naphthene-based hydrocarbons has been studied extensively (35—37), but no commercially viable processes are known. Extensive purification schemes must be employed to maximize naphthene content in the feedstock and remove hydroxy acids and nonacidic by-products from the oxidation product. Free-radical addition of carboxylic acids to olefins (38,39) and addition of unsaturated fatty acids to cycloparaffins (40) have also been studied but have not been commercialized. 

Free radical additions to mono-olefins are quite common and can frequently be employed to advantage on a synthetic scale. Formamide, for example, on exposure to sunlight or UV radiation adds to olefins in an anti-Markovnikov sense giving 1 1 adducts that are readily isolated and crystallized. Moreover, since alkyl formamides may be conveniently converted to carboxylic acids by conventional means, the reaction represents a general method of chain extension. 

The observation that addition of imidazoles and carboxylic acids significantly improved the epoxidation reaction resulted in the development of Mn-porphyrin complexes containing these groups covalently linked to the porphyrin platform as attached pendant arms (11) [63]. When these catalysts were employed in the epoxidation of simple olefins with hydrogen peroxide, enhanced oxidation rates were obtained in combination with perfect product selectivity (Table 6.6, Entry 3). In contrast with epoxidations catalyzed by other metals, the Mn-porphyrin system yields products with scrambled stereochemistry the epoxidation of cis-stilbene with Mn(TPP)Cl (TPP = tetraphenylporphyrin) and iodosylbenzene, for example, generated cis- and trans-stilbene oxide in a ratio of 35 65. The low stereospecificity was improved by use of heterocyclic additives such as pyridines or imidazoles. The epoxidation system, with hydrogen peroxide as terminal oxidant, was reported to be stereospecific for ris-olefins, whereas trans-olefins are poor substrates with these catalysts. 

No. Carboxylic acid Olefin Additive monomer (%-yield) Additive dimer (%-yield) Ref. 

In addition, also nonheme iron catalysts containing BPMEN 1 and TPA 2 as ligands are known to activate hydrogen peroxide for the epoxidation of olefins (Scheme 1) [20-26]. More recently, especially Que and coworkers were able to improve the catalyst productivity to nearly quantitative conversion of the alkene by using an acetonitrile/acetic acid solution [27-29]. The carboxylic acid is required to increase the efficiency of the reaction and the epoxide/diol product ratio. The competitive dihydroxylation reaction suggested the participation of different active species in these oxidations (Scheme 2). 

The first commercial Fischer-Tropsch facility was commissioned in 1935, and by the end of the Second World War a total of fourteen plants had been constructed. Of these, nine were in Germany, one in France, three in Japan, and one in China. Both German normal-pressure and medium-pressure processes (Table 18.1) were employed. The cobalt-based low-temperature Fischer-Tropsch (Co-LTFT) syncrude produced in these two processes differed slightly (Table 18.2), with the product from the medium-pressure process being heavier and less olefinic.11 In addition to the hydrocarbon product, the syncrude also contained oxygenates, mostly alcohols and carboxylic acids. 

The most characteristic and useful reaction is the dimerization with incorporation of certain nucleophiles. It is well-known that simple olefins coordinated by Pd2+ compounds undergo nucleophilic substitutions [Eq. (9)] or addition reactions [Eq. (10)] (16, 17). Water, alcohols, and carboxylic acids are typical nucleophiles which attack olefins to form aldehydes, ketones, vinyl ethers, and vinyl esters. 

In the 1990s, the groups of Hiemstra and Larock independently discovered that Pd(OAc)2 in DMSO serves as an effective catalyst for direct dioxygen-coupled catalytic turnover, and this catalyst system was applied widely to oxidative heterocyclization reactions. Examples include the addition of carboxylic acid, phenol, alcohol, formamide, and sulfonamide nucleophiles to pendant olefins (Eq. 26) [146-149]. 

Ion 24 can either lose a proton or combine with chloride ion. If it loses a proton, the product is an unsaturated ketone the mechanism is similar to the tetrahedral mechanism of Chapter 10, but with the charges reversed. If it combines with chloride, the product is a (3-halo ketone, which can be isolated, so that the result is addition to the double bond (see 5-34). On the other hand, the p-halo ketone may, under the conditions of the reaction, lose HC1 to give the unsaturated ketone, this time by an addition-elimination mechanism. In the case of unsymmetrical olefins, the attacking ion prefers the position at which there are more hydrogens, following Markovnikov s rule (p. 750). Anhydrides and carboxylic acids (the latter with a proton acid such as anhydrous HF, H2S04, or polyphosphoric acid as a catalyst) are sometimes used instead of acyl halides. With some substrates and catalysts double-bond migrations are occasionally encountered so that, for example, when 1-methylcyclohexene was acylated with acetic anhydride and zinc chloride, the major product was 6-acetyl-l-methylcyclohexene.198... 

Carboxylic esters are produced by the addition of carboxylic acids to olefins, a reaction that is usually acid-catalyzed (by proton or Lewis acids182) and similar in mechanism to 5-4. Since Markovnikov s rule is followed, hard-to-get esters of tertiary alcohols can be prepared from olefins of the form R2C=CHR.183 When a carboxylic acid that contains a double bond in the chain is treated with a strong acid, the addition occurs internally and the product is a y- and/or a 8-lactone, regardless of the original position of the double bond in the chain, since strong acids catalyze double bond shifts (2-2).184 The double bond always migrates to a position favorable for the reaction, whether this has to be toward or away from the carboxyl group. Carboxylic esters have also been prepared by the acyloxymercuration-demercuration of olefins (similar to the procedures mentioned in 5-2 and 5-4).185... 

Olefins react with manganese(III) acetate to give 7-lactones.824 The mechanism is probably free-radical, involving addition of CH2COOH to the double bond. Lactone formation has also been accomplished by treatment of olefins with lead tetraacetate,825 with a-bromo carboxylic acids in the presence of benzoyl peroxide as catalyst,826 and with dialkyl malonates and iron(III) perchlorate Fe(C104)3-9H20.827 Olefins can also be converted to 7-lactones by indirect routes.828 OS VII, 400. 

There are actually three reactions called by the name Schmidt reaction, involving the addition of hydrazoic acid to carboxylic acids, aldehydes and ketones, and alcohols and olefins.227 The most common is the reaction with carboxylic acids, illustrated above.228 Sulfuric acid is the most common catalyst, but Lewis acids have also been used. Good results are obtained for aliphatic R, especially for long chains. When R is aryl, the yields are variable, being best for sterically hindered compounds like mesitoic acid. This method has the advantage over 8-14 and 8-15 that it is just one laboratory step from the acid to the amine, but conditions are more drastic.229 Under the acid conditions employed, the isocyanate is virtually never isolated. 

Addition of alkylcopper reagents to unsaturated carboxylic acids 5-22 Free-radical addition of acids to olefins... 

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