Degradation adipic acid

Adipic Acid Degradation / Adipic Acid V Sulfite Oxidation ... 

The odor has been identified as that of valeric acid, CH3(CH2)3 COOH, an intermediate product formed by side reactions that degrade adipic acid at scrubber operating conditions. At Shawnee, this odor was rarely noticed and was not a problem. 

Putrescine dihydrochloride has been prepared by the Hofmann degradation of adipamide 3.. s by the Curtius degradation of adipyl hydrazide through the urethane by the Curtius degradation of adipyl azide obtained from adipyl chloride and sodium azide by the Schmidt degradation of adipic acid with hydrogen azide by the reduction of succinonitrile, succinaldoxime, or 7-phthalimidobutyronitrile with sodium and from N-ben-zoyl-7-iodobutylamine ... 

In order to obtain information regarding the composition of these degradation products, aqueous extracts of the lead soaps of the linseed oil fatty acids were analysed, mainly by chromatography. The extracts contained formic acid 46%, azelaic acid 9% and pelargonic acid and its derivatives 27%, the remaining 18% consisting of a mixture of acetic, propionic, butyric, suberic, pimelic and adipic acids. It was shown that whereas the salts of formic acid were corrosive, those of azelaic and pelargonic acid were very efficient inhibitors. 

To reduce the chance of side reactions, such as the dimerization of the diamine to tUjtw -diaminodihexylamine in (3.17) and the degradation of adipic acid to Schiff bases in (3.16), the precondensation can be carried out either for 30-60 min below 250°C or very rapidly (seconds) at 250-290°C. In the (pre)polymerization step, a concentrated PA salt solution is pumped into a set of heating tubes. These tubes have several heating zones as their diameter gradually increases in size.5,6,28... 

Biological. Microbial degradation products reported include cyclohexanol (Dugan, 1972 Verschueren, 1983), l-oxa-2-oxocycloheptane, 6-hydroxyheptanoate, 6-oxohexanoate, adipic acid, acetyl-CoA, succinyl-CoA (quoted, Verschueren, 1983), and cyclohexanone (Dugan, 1972 Keck et al 1989). 

Galbis et al. described a variety of carbohydrate-based linear polyesters 61 of the poly(alkylene dicarboxylate) type that were obtained by polycondensation reactions of the alditols 2,3,4-tri-(9-methyl-L-arabinitol (9) and 2,3,4-tri-O-methyl-xylitol (10), and the aldaric acids 2,3,4-tri-(9-methyl-L-arabinaric acid (26) and 2,3,4-tri-(9-methyl-xylaric acid (27), butanediol, and adipic acid were also used as comonomers [28]. Copolyesters of the poly(aIkylene-c )-arylene dicarboxylate) type were obtained using bisphenols as comonomers (Scheme 1). Chemical polycondensation reactions were conducted in bulk or in solution. Enzymatic polycondensation reactions of adipic acid with the above-mentioned alditols were carried out successfully using Lipozyme and Novozyme 435. The hydrolytic degradations of some of these polyesters were also described. 

Saeger, YW., Kaley, R.G, II, Hicks, O., Tucker, E.S. Mieure, J.P. (1976) Activated sludge degradation of adipic acid esters. Appl. environ. Microbiol., 31, 746-749 Seed, J.L. (1982) Mutagenic activity of phthalate esters in bacterial liquid suspension assays. Environ. Health Perspect., 45, 111-114... 

Hexamethylenediamine (HMDA) is a colorless solid when pure, but it slowly degrades to colored products when it contacts air. It is commercially available as the anhydrous product or in aqueous solutions. In 2003 it had a global capacity that was approaching 3.0 billion pounds per year, and it was made by only one main route hydrogenation of ADN. Commercially the most important use of HMDA is in a polycondensation reaction with adipic acid to eventually give nylon 6,6274. The chemical formula for HMDA is ... 

Another synthesis of adipic acid involves the microbial degradation of toluene to muconic acid (hexa-2,4-dienedioic acid), which undergoes catalytic hydrogenation to give adipic acid. If this process can be made economically competitive, it might produce less environmental impact than the chemical synthesis from benzene. 

The solution is a combination of aliphatic polyesters and aromatic polyesters. This involves modifying the crystalline structure of PBT by incorporating aliphatic monomer (adipic acid) in the polymer chain in such a way that the material properties of the polymer would remain acceptable (e.g., melting point of the crystalline range still around 100 °C), but the polymer would also be readily compostable/biodegradable. In this way it was possible to combine the degradability of aliphatic polyesters with the outstanding properties of aromatic polyesters. 

Adipic acid aliphatic copolyesters Biodegradable polyester used in degradable plastic... 

Environmental Aspects. Airborne particulate matter (187) and aerosol (188) samples from around the world have been found to contain a variety of organic monocarboxylic and dicarboxylic acids, including adipic acid. Traces of the acid found in southern California air were related both to automobile exhaust emission (189) and, indirectly, to cyclohexene as a secondary aerosol precursor (via ozonolysis) (190). Dibasic acids (eg, succinic acid) have been found even in such unlikely sources as the Murcliison meteorite (191). Public health standards for adipic acid contamination of reservoir waters were evaluated with respect to toxicity, odor, taste, transparency, foam, and other criteria (192). Bio degradability of adipic acid solutions was also evaluated with respect to BOD/theoretical oxygen demand ratio, rate, lag time, and other factors (193). 

As in other polycondensations at high temperatures, there are several side reactions that occur during the melt polycondensation of diamines and dicarboxylic acids. One has already been mentioned in Section 5.2 decarboxylation. As shown in the list of decarboxylation temperatures for a homologous series of dicarboxylic acids (Table 2), adipic acid begins to decarboxylate at around 300°C. In commercial practice, the maximum temperature that nylon-6,6 experiences during its preparation is about 290°C, so that decarboxylation is one of the most important degradation reactions of nylon-6,6. Nylon-6 and nylon-6,10 are more thermally stable than nylon-6,6. 

Fig. 4 Comparison of the degradation of different polyamides by adipic acid [AdAc] and trimellitic anhydride [TMAn]...

The results of the controlled degradation of several polyamides by trimellitic anhydride and adipic acid demonstrate the reproducibility of the degradation reaction, as shown in Fig. 4. 

Metal oxide semiconductor chemical sensors in combination with MDA have been shown to be useful to estimate the oxidative stability of polypropylene during processing instead of traditional melt flow index analysis (50). An array of sensors was used to receive a detailed analysis of volatiles. At quality measurements of different poly(butylene adipate)s the use of indicator products has been proven better than analyses of the decrease in molecular weight or mass loss for early degradation detection. Adipic acid, quantified using gas chromatography, was then used as the indicator product [51]. 

Laboratory Investigation of Adipic Acid Degradation in Flue Gas Desulfurization Scrubbers... 

The addition of adipic acid to limestone-based FGD wet scrubbers results in improved limestone utilization and enhanced S02 sorption kinetics. The use of adipic acid was first proposed by Rochelle (1) and has been tested by the EPA in pilot systems at the Industrial Environmental Research Laboratory, Research Triangle Park, North Carolina and at the TVA Shawnee Test Facility at Paducah, Kentucky. Adipic acid in the concentration range of 1,000-2,000 mg/1 has been found effective as a scrubber additive. During scrubber operation, however, adipic acid is lost from the system in the liquid and solid phase purge streams and by chemical degradation (2,3). 

Tests conducted at the Shawnee Test Facility indicated that adipic acid added to their limestone FGD scrubber did not degrade at pH s below 5. Since these unexpected but favorable results were important to the future application of adipic acid as an FGD additive, independent verification was desired. Radian was contracted by the EPA to carry out a systematic study of the effects of scrubber operating conditions on adipic acid degradation. 

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