Dimer acid esters

Acryhc esters dimerize to give the 2-methylene glutaric acid esters catalyzed by tertiary organic phosphines (37) or organic phosphorous triamides, phosphonous diamides, or phosphinous amides (38). Yields of 75—80% dimer, together with 15—20% trimer, are obtained. Reaction conditions can be varied to obtain high yields of trimer, tetramer, and other polymers. 

Nonfood Uses. Vegetable oils are utilized in a variety of nonedible applications, but only a few percent of the U.S. soybean oil production is used for such products (see Table 13). Soybean oil is converted into alkyd resins (qv) for protective coatings, plasticizers, dimer acids, surfactants (qv), printing inks, SoyDiesel fuel (methyl esters used to replace petroleum-based diesel fuel) and other products (76). 

The mixed oxidation products are fed to a stiU where the pelargonic and other low boiling acids are removed as overhead while the heavy material, esters and dimer acids, are removed as residue. The side-stream contains predominately azelaic acid along with minor amounts of other dibasic acids and palmitic and stearic acids. The side-stream is then washed with hot water that dissolves the azelaic acid, and separation can then be made from the water-insoluble acids, palmitic and stearic acids. Water is removed from the aqueous solution by evaporators or through crystallization (44,45). 

The foUowiag are three possible stmctures of the methyl esters of dimer acids. 

The most important coating appHcation for the nonreactive polyamide resins is in producing thixotropy. Typical coating resins such as alkyds, modified alkyds, natural and synthetic ester oils, varnishes, and natural vegetable oils can be made thixotropic by the addition of dimer acid-based polyamide resins (see Alkyd resins). Specialty high performance coating appHcations often requite the properties imparted by dimer acid components. 

Miscellaneous Commercial Applications. Dimer acids are components of "downweU" corrosion inhibitors for oil-drilling equipment (see Petroleum Corrosion and corrosion inhibitors). This may account for 10% of current dimer acid use (71). The acids, alkyl esters, and polyoxyalkylene dimer esters are used commercially as components of metal-working lubricants (see Lubrication). Dimer esters have achieved some use in specialty lubricant appHcations such as gear oils and compressor lubricants. The dimer esters, compared to dibasic acid esters, polyol esters and poly(a-olefin)s, are higher in cost and of higher viscosity. The higher viscosity, however, is an advantage in some specialties, and the dimer esters are very stable thermally and can be made quite oxidatively stable by choice of proper additives. 

Although most of the macrocycles that contain phosphorus or arsenic which have thus far been prepared, are primarily transition metals binders, two compounds have been prepared which are essentially crown ethers containing phosphorus. Kudrya, Shtepanek and Kirsanovhave prepared two compounds which are essentially polyoxygen macrocycles but which contain one or two methylphosphonic acid esters as part of the ring. These two macrocycles are shown below as 7d and 17 and are both prepared by the reaction of 2,2 [oxybis(ethyleneoxy)] bisphenolate with methylphosphonic dichloride in a mixture of acetonitrile and benzene. The crystalline monomer 16) and dimer 17) were isolated in 17% and 11% yields respectively as indicated in Eq. (6.13). 

Two types of sulfonate esters can be formed in the production of AOS. Neutral esters are formed by the addition of alkenesulfonic acid to alkene (Fig. 29). Acid esters are formed by the dimerization of two alkene mono- or disulfonic acids (Fig. 30). These would normally be expected to hydrolyze in the saponification stage of the process. 

The Emser Industries process has no ester linkage, the bonds between the two segments being amides. An amine-terminated soft bis(3-aminopropyl)polyoxytetramethylene glycol is reacted with a dimer acid (Empol 1010) and caprolactum to form polyetheramide (PETA). 

Dimethyl peroxide Diethyl peroxide Di-t-butyl-di-peroxyphthalate Difuroyl peroxide Dibenzoyl peroxide Dimeric ethylidene peroxide Dimeric acetone peroxide Dimeric cyclohexanone peroxide Diozonide of phorone Dimethyl ketone peroxide Ethyl hydroperoxide Ethylene ozonide Hydroxymethyl methyl peroxide Hydroxymethyl hydroperoxide 1-Hydroxyethyl ethyl peroxide 1 -Hydroperoxy-1 -acetoxycyclodecan-6-one Isopropyl percarbonate Isopropyl hydroperoxide Methyl ethyl ketone peroxide Methyl hydroperoxide Methyl ethyl peroxide Monoperoxy succinic acid Nonanoyl peroxide (75% hydrocarbon solution) 1-Naphthoyl peroxide Oxalic acid ester of t-butyl hydroperoxide Ozonide of maleic anhydride Phenylhydrazone hydroperoxide Polymeric butadiene peroxide Polymeric isoprene peroxide Polymeric dimethylbutadiene peroxide Polymeric peroxides of methacrylic acid esters and styrene... 

Decomposition of diazoacetate in 2,5-dimethyl-2,4-hexadiene (3 equiv relative to diazoacetate) leads to the pyrethroid chrysanthemic acid esters with moderate enantioselectivity (68% ee trans, 62% ee cis) but poor diastereoselectivity (58 42 trans to cis), Eq. 5. Both the dimer and the pyridyl monomer were found to be equally effective in this reaction. 

In polymer applications derivatives of oils and fats, such as epoxides, polyols and dimerizations products based on unsaturated fatty acids, are used as plastic additives or components for composites or polymers like polyamides and polyurethanes. In the lubricant sector oleochemically-based fatty acid esters have proved to be powerful alternatives to conventional mineral oil products. For home and personal care applications a wide range of products, such as surfactants, emulsifiers, emollients and waxes, based on vegetable oil derivatives has provided extraordinary performance benefits to the end-customer. Selected products, such as the anionic surfactant fatty alcohol sulfate have been investigated thoroughly with regard to their environmental impact compared with petrochemical based products by life-cycle analysis. Other product examples include carbohydrate-based surfactants as well as oleochemical based emulsifiers, waxes and emollients. 

The ring-opening polymerization of dilactide (dimeric cyclic ester of lactic acid) allows the preparation of high molecular weight, optically active polyesters of lactic acid. The configuration of the asymmetric carbon atoms of the monomer is retained when the polymerization is initiated with SnCl4 or Et2Zn, for example ... 

A methoxylated polyamide 78 analogous to Nylon 6 was obtained in several steps fi om D-glucose [61, 63] through the preparation of a dimeric active ester of 6-amino-6-deoxy-2,3,4,5-tetra-(9-methyl-D-gluconic acid (49). This polyamide was highly crystalline, and gave resistant films with a spherulitic texture. 

The Brown- Walker Electrolysis is useful for dimerizing half-acid-esters ... 

The analysis of polymerized fatty acids (also termed dimer acid) for neutrals, monomers dimer, and polymer has been approached by means of many different techniques, but a truly satisfactory solution remained elusive until 2 or 3 years ago. Many early analyses were done by distillation of the methyl esters, but the integrity of the sample is compromised when subjected to severe distillation conditions. Chromatographic methods have the greatest promise for this analysis, and some success has been realized in applying these techniques. 

Figure 2.8 Summary of behavior of phenolic acid esters and free forms in the GIT and the liver. 5-O-CQA, 5-O-caffeoylquinic acid 5-O-FAAF, 5-O-feruloyl-L-arabinofura-nose C, conjugate (sulfate, glucuronide or methyl) CA, caffeic acid FA, ferulic acid FA-FA, dimer of ferulic acid FA-oligosac., ferulic acid esterified to an oligosaccharide FA-Xy, ferulic acid esterified to xylan R, alkyl group.

Acyl anions (RC(=0)M) are unstable, and quickly dimerize at temperatures >-100 °C (Section 5.4.7). These intermediates are best generated by reaction of organolithium compounds or cuprates with carbon monoxide at -110 °C and should be trapped immediately by an electrophile [344—347]. Metalated formic acid esters (R0C(=0)M) have been generated as intermediates by treatment of alcoholates with carbon monoxide, and can either be protonated to yield formic acid esters, or left to rearrange to carboxylates (R0C(=0)M —> RC02M) (Scheme 5.38) [348]. Related intermediates are presumably also formed by treatment of alcohols with formamide acetals (Scheme 5.38) [349]. More stable than acyl lithium compounds are acyl silanes or transition metal acyl complexes, which can also be used to perform nucleophilic acylations [350],... 

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