Dimethyl sebacate

An electrooxidation process was developed by Asahi Chemical Industry ia Japan, and was also piloted by BASF ia Germany. It produces high purity sebacic acid from readily available adipic acid. The process consists of 3 steps. Adipic acid is partially esterified to the monomethyl adipate. Electrolysis of the potassium salt of monomethyl adipate ia a mixture of methanol and water gives dimethyl sebacate. The last step is the hydrolysis of dimethyl sebacate to sebacic acid. Overall yields are reported to be about 85% (65). 

Another alternative method to produce sebacic acid iavolves a four-step process. First, butadiene [106-99-0] is oxycarbonylated to methyl pentadienoate which is then dimerized, usiag a palladium catalyst, to give a triply unsaturated dimethyl sebacate iatermediate. This unsaturated iatermediate is hydrogenated to dimethyl sebacate which can be hydrolyzed to sebacic acid. Small amounts of branched chain isomers are removed through solvent crystallizations giving sebacic acid purities of greater than 98% (66). 

Seb cic Acid. Sebacic acid [111-20-6] C QH gO, is an important intermediate in the manufacture of polyamide resins (see Polyamides). It has an estimated demand worldwide of approximately 20,000 t/yr. The alkaline hydrolysis of castor oil (qv), which historically has shown some wide fluctuations in price, is the conventional method of preparation. Because of these price fluctuations, there have been years of considerable interest in an electrochemical route to sebacic acid based on adipic acid [124-04-9] (qv) as the starting material. The electrochemical step involves the Kolbn-type or Brown-Walker reaction where anodic coupling of the monomethyl ester of adipic acid forms dimethyl sebacate [106-79-6]. The three steps in the reaction sequence from adipic acid to sebacic acid are as follows ... 

Decamethylene glycol has been prepared by the reduction of dimethyl sebacate and diethyl sebacate with sodium and ethyl alcohol by the reduction of sebacamide with sodium and amyl alcohol and by the reduction of dimethyl sebacate with sodium and liquid ammonia in absolute alcohol. The reduction of esters with sodium and alcohol has also been applied to the preparation of many other glycols. ... 

In Russia in the 1960s, an industrial production of sebacic acid, HCOOC (CH2)4 COOH (an important intermediate for different plastics), was started which involves the anodic condensation of monomethyl adipate CH300C(CH2)4C00 . Dimethyl sebacate is obtained via the scheme of (15.58), and then hydrolyzed in autoclaves to the final product. Methanol is used as a solvent to lower the rates of side reactions. The reaction occurs with current yields attaining 75% and with chemical yields (degrees of utilization of the original adipate) of 82 to 84% (Vassihev et al., 1982). Upon introduction of this process it was no longer necessary to use castor oil, an expensive raw material that was needed to produce sebacic acid by the chemical process. 

The overall yield of cyclodecanone is comparable to the overall yield obtained by conversion of dimethyl sebacate to sebacoin 11 and subsequent reduction to cyclodecanone.6 In addition, the present procedure does not require the use of a high-speed stirrer, the rigorous exclusion of air, and the high dilution that are necessary in preparing sebacoin. 

Kolbe coupling of half esters Monomethyl adipate - Dimethyl sebacate Europe, India, Japan n/a Pt anode in methanol... 

Dimethylquinoline, 21 189 Dimethyl sebacate, from adipic acid,... 

In Japan the need for new technology was answered by the development of an electrolytic route to sebacic acid(33). The Kolbe type electrolytic process developed by Asahi involves dimerization of adipic acid half methyl ester salt to give dimethyl sebacate(34). The dimerization proceeds in 92% yield with 90% selectivity based on the adipate half ester. The main drawbacks of this process are the cost of energy utilized by the electrolytic process and the cost of adipic acid. A Chem Systems report indicates a small advantage for the Asahi electrolytic process with ample room for new technology development(35). 

The isolated dimethyl sebacate can be sold commercially as is or optionally hydrolyzed to sebacic acid. If a higher molecular weight plasticizer diester is required, a transesterification with -ethyl hexanol, for example, gives the desired product plus two equivalents of methanol which is recycled back to the oxycarbonylation reaction. If the free acid is desired, dimethyl sebacate hydrolysis to sebacic acid is carried out using a strong mineral acid such as sulfuric acid. Hydrolysis is nearly quantitative with a selectivity of about 99.5% to diacid and. 5% to the half-ester acid product. Additional recrystallization is used to improve purity if required. 

Ethyl 10-undecenoate ozonide was autoxidized at 95% in the absence of a catalyst. Diethyl sebacate, methyl ethyl sebacate, and dimethyl sebacate were detected after diazomethane treatment. When the ozonide was oxidized in acetone over platinum black and similarly treated with diazomethane, dimethyl sebacate could not be detected. 

A. Zinc Reduction-Volumetric Procedure (Ref l6a, Method 203-5)- This method is used for determining the DBuPh and DEtPh content of proplnts that do not contain interfering esters such as other phthalates, dimethyl sebacate, triacetin, or sucrose octa-acetate... 

Dimethyl Sebacate (DMeSeb) (Called Meibylsebacate by some investigators),... 

Dimethylpyrazole, 842 2 5-Dimethyl pyrrole, 839 Dimethyl sebacate, 938, 939,940 aa-Dimethylsuccinic acid, 490, 495 Dimethyl sulphate, 303... 

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