Sodium carboxylate

CMC hydrates rapidly and forms clear solutions. Viscosity buUding is the single most important property of CMC. DUute solutions of CMC exhibit stable viscosity because each polymer chain is hydrated, extended, and independent. The sodium carboxylate groups are highly hydrated, and the ceUulose molecule itself is hydrated. The ceUulose molecule is linear, and conversion of it into a polyanion (polycarboxylate) tends to keep it in an extended form by reason of coulombic repulsion. This same coulombic repulsion between the carboxylate anions prevents aggregation of the polymer chains. Solutions of CMC are either pseudoplastic or thixotropic, depending on the type. 

In addition to their work on naphthocoumarins, Sen and Kakaji showed that 4-t-butyl-2-hydroxyphenones 50 gave exclusively coumarins 51 when treated with various anhydrides in the presence of their corresponding sodium carboxylates. They saw similar results with 4-t-amyl-2-hydroxyphenones. 

Lemiere and coworkers synthesized the antipicomavirus agent 3-0-Methylquercetin (76). A key transformation was the conversion of acetophenone 61a to 3-methoxyflavone 79. In the event, 61a and 3,4-dibenzyloxybenzoic anhydride (77) were allowed to react at 160 C in the presence of sodium carboxylate 78 to deliver the penultimate intermediate in 78% yield. Debenzylation of 79 in the presence of Pearlman s catalyst delivered the natural product in 99% yield. 

The sodium carboxylates resulting from hydrolyzable tannins are similar to the gluconates and sarcosinates commonly employed as... 

The solution is allowed to stand in a separatory funnel for at least 30 min before the aqueous layer is drained out. It is sometimes observed that a portion of the sodium carboxylate salt of 4 forms a third layer below the aqueous layer, in which case this layer should be combined with the sodium carbonate... 

The synthesis of chaparrinone and other quassinoids (naturally occurring substances with antileukemic activity) is another striking example [16a-c]. The key step of synthesis was the Diels-Alder reaction between the a,/l-unsaturated ketoaldehyde 1 (Scheme 6.1) with ethyl 4-methyl-3,5-hexadienoate 2 (R = Et). In benzene, the exo adduct is prevalent but it does not have the desired stereochemistry at C-14. In water, the reaction rate nearly doubles and both the reaction yield and the endo adduct increase considerably. By using the diene acid 2 (R = H) the reaction in water is 10 times faster than in organic solvent and the diastereoselectivity and the yield are satisfactory. The best result was obtained with diene sodium carboxylate 2 (R = Na) when the reaction is conducted 2m in diene the reaction is complete in 5h and the endo adduct is 75% of the diaster-eoisomeric reaction mixture. 

Foreign cations can increasingly lower the yield in the order Fe, Co " < Ca " < Mn < Pb " [22]. This is possibly due to the formation of oxide layers at the anode [42], Alkali and alkaline earth metal ions, alkylammonium ions and also zinc or nickel cations do not effect the Kolbe reaction [40] and are therefore the counterions of choice in preparative applications. Methanol is the best suited solvent for Kolbe electrolysis [7, 43]. Its oxidation is extensively inhibited by the formation of the carboxylate layer. The following electrolytes with methanol as solvent have been used MeOH-sodium carboxylate [44], MeOH—MeONa [45, 46], MeOH—NaOH [47], MeOH—EtsN-pyridine [48]. The yield of the Kolbe dimer decreases in media that contain more than 4% water. 

Preparation and Reactions of S-b-MM. As mentioned in the introduction, we were interested in block copolymers of styrene and alkali metal methacrylates with overall molecular weights of about 20,000 and methacrylate contents on the order of 10 mol%. The preparation of such copolymers by the usual anionic techniques is not feasible. An alternative is to prepare block copolymers of styrene and methacrylic esters by sequential anionic polymerization, followed by a post-polymerization reaction to produce the desired block copolymers. The obvious first choice of methacrylic esters is methyl methacrylate. It is inexpensive, readily available, and its block copolymers with styrene are well-known. In fact, Brown and White have reported the preparation and hydrolyses of a series of S-b-MM copolymers of varying MM content using p-toluenesulfonic acid (TsOH) (6). The resulting methacrylic acid copolymers were easily converted to their sodium carboxylates by neutralization with sodium hydroxide. 

Many acrylic acid copolymers are water-soluble but unlike poly(vinyl alcohol) they are not degraded by alkali. In fact they need alkali for effective desizing as they are more soluble at alkaline pH than in neutral solutions. They are sensitive to acidic media, which should not be used. Solubilisation occurs by the formation of sodium carboxylate groups from the anionic polyacid. The polyelectrolyte formed in this way is readily soluble and shows a rapid rate of dissolution. However, the presence of electrolytes such as magnesium or calcium salts from hard water can inhibit removal [191]. 

Damas, C., Vannier, L., Naejus, R. and Coudert, R. (1999) Influence of structural modifications near the polar head of sodium carboxylates on their aqueous solution behaviour. Colloids and Surfaces A Physicochemical and Engineering Aspects, 152, 183-187. 

A-Acyloxy-A-alkoxyamidcs 20 are synthesised from A-chlorohydroxamic esters 22 by replacement of chlorine by a carboxyl group (Scheme 3). Initially we employed silver acetate in anhydrous ether to make A-acetoxy derivatives.47 However, most have been made using sodium carboxylates in dry acetone by analogy with Finkelstein chemistry.5,38 40>42,43,46,48,49,i05 reacti0ns can be monitored conveniently by thin layer chromatography and A-acyloxy-A-alkoxyamides generally... 

Pyrene was used as a fluorescent probe to sense various hydrophobic sites in the microheterogeneous architecture offered by PAMAM dendrimers, possessing an ammonia core and sodium carboxylated surface (Gn.5, n = 0-9) [17]. The IJIi ratio of pyrene in the presence of low generations (G0.5-G3.5) remained very similar to those in pure water. In the presence of higher generation dendrimers, however, pyrene sensed a more hydrophobic outer surface which was presum-... 

High yields of dihydrofurans are obtained from the reaction of the cyclopropyl-phosphonium salt (161) with sodium carboxylates.143... 

Heterocycles.—The phosphonium salt (59) is an effective three-carbon synthon, as demonstrated by its reaction with enolates of /9-keto-esters (Scheme 20) to give cyclopentenyl sulphides via an intramolecular Wittig reaction.63 Ylides are also intermediates in the synthesis of dihydrofurans (60) from the cyclopropylphos-phonium salt (61) and sodium carboxylates (Scheme 21).64 Cumulated ylides are very useful for the synthesis of heterocyclic compounds, e.g. (62), from molecules which contain both an acidic Y—H bond and a carbonyl or nitroso-function, as shown in Scheme 22.65... 

Method A The sodium carboxylate (2 mol) and Aliquat (10 g, 25 mmol) in an excess of the haloalkane (5 mol) are heated at ca. 100°C with vigorous stirring. Either (a) H20 (350 ml) is added and organic phase system is separated, dried (Na2SO ), and fractionally distilled or (b) Et20 (50 ml) is added to the cooled reaction mixture and the solution is filtered through a pad of Florosil and fractionally distilled to yield the ester. 

Table I shows the five-day biochemical oxygen demand (BOD5 ) of some poly(sodium carboxylate)s and poly(vinyl alcohoDs (PVA). The BOD5 test according to JIS K 0102 is only an indication of susceptibility of products to biodegradation, but the test is often an useful tool for rapid screening. As shown in Table I, PMLA and...

Biodegradation of Polyvinyl-Type Poly(sodium carboxylate). PVA is the only substance which is known to be biodegradable in the class of polyvinyl-type synthetic polymer. It may be biodegraded by oxidizing hydroxyl group of PVA to the corresponding carbonyl group and subsequent hydrolysis as shown below (17, 18). 

As a design to develop a polyvinyl-type poly(sodium carboxylate), acrylate copolymers containing hydroxyl or carbonyl groups which are susceptible to the enzymatic reaction, were prepared. It is presumed that the copolymer is first cleaved at a hydroxyl or carbonyl group as in the case of PVA, then the resultant acrylate oligomer is further assimilated by the microbes. The biodegradation of oligomeric acrylic acid (11), in fact, occurs as shown in Table I. 

Biodegradation of poly(sodium carboxylate) containing a glycopyranosyl group, Poly(sodium carboxylate)s containing... 

Detergency Building Performance. Detergency building performances of poly(sodium carboxylate)s were examined using a heavy duty detergent formulation on standard soiled cotton cloths. The detergency expressed as a value relative to 10 for STPP and 0 for disodium 3-oxapentanedioate(0DA) was shown below. 

Poly(sodium carboxylate)s containing hydroxyl, ester, carbonyl or glycopyranosyl groups in the polymer chain showed an improved biodegradability, suggesting these functional groups to be useful as... 

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