Aqueous glycolic acid

A 3-1. stainless steel, rocking autoclave (Note 1) is charged with 270 g. (4.1 moles) of 85% potassium hydroxide and 351 g. (3.00 moles) of indole (Note 2), and then 360 g. (3.3 moles) of 70% aqueous glycolic acid is added gradually (Note 3). The autoclave is closed and rocked at 250° for about 18 hours (Note 4). The reaction mixture is cooled to below 50°, 500 ml. of water is added, and the autoclave is rocked at 100° for 30 minutes to dissolve the potassium indole-3-acetate. The aqueous solution is cooled to 25° and removed from the autoclave, the autoclave is rinsed out well with water, and water is added until the total volume of solution is 3 1. The solution is extracted with 500 ml. of ether (Note 5). The aqueous phase is acidified at 20-30° with 121V hydrochloric acid and then is cooled to 10° (Note 6). The indole-3-acetic acid that precipitates is collected on a Buchner funnel, washed with copious amounts of cold water, and dried in air or a vacuum desiccator out of direct light (Note 7) weight 455-190 g. (87-93%) m.p. 163-165° (dec.). 

Figure 8 (47) shows the effect of modifying temperature on the EDA of MRNi prepared from RNi pretreated with 1% aqueous glycolic acid at 100°C for 1 hr [RNiA (GA)j. Results obtained with MRNi without pretreatment also are shown in Fig. 8 for comparison. Only a small effect of modifying temperature on EDA was observed with MRNiA and the greater EDA was obtained with RNiA. Especially in the case of modification with... 

CH2OHCOONH4 (aq.). de Forcrand3 measured the heat of neutralization of aqueous glycollic acid with aqueous ammonia. 

This behavior is analogous to that of aqueous glycolic acid. The carbon-carbon scission which occurs in oxygen is diminished under vacuum. - Similarly, dimerization is only observed in the absence of oxygen. 

Table 20 Rf Values of Metal Ions on Silica Layer with Aqueous Glycolic Acid Media...

The first catalysts reported for the electroreduction of C02 were metallophthalocyanines (M-Pc).126 In aqueous solutions of tetraalkylammonium salts, current-potential curves at a cobalt phthalocyanine (Co-Pc)-coated graphite electrode showed a reduction current peak whose height was proportional to the C02 concentration and to the square root of the potential sweep rate at a given C02 concentration. On electrolysis, oxalic acid and glycolic acid were detected, but formic acid was not. Mn and Pd phthalocyanines were inactive, while Cu and Fe phthalocyanines were slightly active. At the potentials used for C02 reduction, M-Pc catalysts would be in their dinegative state, and the occupied dz2 orbital of the metal ion in the metallophthalocyanine was suggested to play an important role in the catalytic activity. 

Reeder and Rieger6 used ESR spectra to identify complex ions and to estimate formation constants for aqueous oxovanadium(iv) complexes with lactic acid, thiolactic acid, glycolic acid, and thioglycolic acid. Through the use of second-harmonic detection, which produces second-derivative spectra, the resolution was good enough that several of the individual species could be separately... 

A mixture of Pt(ll) and metallic Pt in an aqueous medium was shown to oxidize ethane to yield acetic and glycolic acids. A series of deuterium-exchange processes enabled a complex mechanism to be elucidated metallic platinum catalyzes the oxidation of intermediate alcohols to acid products, whereas the Pt(ll) salt activates the initial alkene (Scheme 7X29... 

Cyclopentanecarboxaldehyde has been prepared by the procedure described above 2 3 by the reaction of aqueous nitric acid and mercuric nitrate with cyclohexene 6 by the action of magnesium bromide etherate 6 or thoria 7 on cyclohexene oxide by the dehydration of frarei-l, 2-cyclohexanediol over alumina mixed with glass helices 8 by the dehydration of divinyl glycol over alumina followed by reduction 9 by the reaction of cyclopentene with a solution of [HFe(CO)4] under a carbon monoxide atmosphere 10 and by the reaction of cyclopentadiene with dicobalt octacarbonyl under a hydrogen and carbon monoxide atmosphere.11... 

Beckett and Hua (2000) investigated the sonolytic decomposition of 1,4-dioxane in aqueous solution at 25 °C at discrete ultrasonic frequencies. They found that the highest first-order decomposition rate occurred at 358 kHz followed by 618, 1,071, and 205 kHz. At 358 kHz, 96% of the initial 1,4-dioxane concentration was decomposed after 2 h and the pH of the solution decreased to 3.75 from 7.50. Major decomposition intermediates were ethylene glycol diformate, methoxyacetic acid, formaldehyde, glycolic acid, and formic acid. 

Marchand and co-workers ° synthesis of 5,5,9,9-tetranitropentacyclo[5.3.0.0 .0 °.0 ] decane (52) reqnired the dioxime of pentacyclo[5.3.0.0 .0 °.0 ]decane-5,9-dione (49) for the incorporation of the four nitro groups. Synthesis of the diketone precursor (48) was achieved in only five steps from cyclopentanone. Thus, acetal protection of cyclopentanone with ethylene glycol, followed by a-bromination, and dehydrobromination with sodium in methanol, yielded the reactive intermediate (45), which underwent a spontaneous Diels-Alder cycloaddition to give (46). Selective acetal deprotection of (46) was followed by a photo-initiated intramolecular cyclization and final acetal deprotection with aqueous mineral acid to give the diketone (48). Derivatization of the diketone (48) to the corresponding dioxime (49) was followed by conversion of the oxime groups to gem-dinitro functionality using standard literature procedures. 

Aqueous periodic acid can be used to achieve glycol cleavage, combined with anodic oxidation of the iodate, which is formed, back to periodate [70]. Oxidation of iodate is catalysed at a lead dioxide anode [71] but at the potentials required, aldehydes are oxidised to the corresponding acids. Due to this further reaction, the redox-mediated cleavage of diols to form an aldehyde may be difficult to achieve witli a catalytic amount of periodic acid. Cleavage using a stoichiometric amount of periodic acid, followed by recovery of the iodic acid and then its electochemical oxidation, has been achieved [72]. 

Wirz et al. also studied photorelease of glycolic acid from 96 (Scheme 47). They used spectroscopy to reinforce that the mechanism of photorelease from 96 is similar to that observed for 89. They found that the hydrolysis from 101 limits the release rate from 96 in aqueous solutions at pH < 7. Additionally, they also observed that the release from 98 can be retarded by buffers. As an example, they showed that 98, in aqueous solution, was trapped intramolecularly to form 100, which had lifetimes in the order of minutes. 

The most common synthetic biodegradable polymers for suture material and their corresponding weight loss in aqueous solution are listed in Table 3.10. Of these, poly(glycolic acid), PGA, poly(lactic acid), PLA, and copolymers of these two polyesters are the most widely used for resorbable sutme material. PGA is a tough. 

The occurrence of a similar reaction has recently been indicated by studies carried out in this laboratory (7). If p-hydroxybenzyl alcohol (XXXVI) was oxidized with sodium bismuthate, the spirocyclic epoxy-cyclohexadienone (XXXVII) was obtained. The epoxide ring of this compound was hydrolyzed almost instantaneously by 2N aqueous hydrochloric acid and in a few hours by 10% aqueous acetic acid. However, the expected glycol (XXXVIII) could not be isolated since it decomposed immediately into equimolar amounts of hydroquinone and formaldehyde. (Attempts are now being made to prepare compounds analogous to XXXVIII but containing, in addition to the HOCH2 group, a carbon sub-... 

---