Mud acid

Low solubility in mineral oils (drilling mud), acids, alkalis, organic compounds and solvents. 

The triazene linker can be used for the immobilization of aromatic diazonium salts, and therefore for aromatic amines, but not for aliphatic amines due to the instability of their diazonium salts. Cleavage of the linker can be achieved under mUd acidic conditions to yield the benzylamine resin and the corresponding diazonium salt [136,145,146]. The main difference between the preparation of triazenes in solution and triazenes on solid support is the respective amine, namely bisben-zylamine and polymer-supported benzylamine 114. In solution, it was used in excess to quench unstable diazonium salts and force the reaction to completion. In the solid-phase approach it was immobilized and cannot be used in excess with respect to low loadings. A simple three-step procedure (Scheme 36) starting from benzylamine resin 114 via carboxylate 115 led to the successful preparation of ester resins 116 in essentially higher loadings. Treatment of resin 114 with 4-carboxy-benzene diazonium tetrafluoroborate yielded benzoic acid resin 115. 

Particularly useful synthetically is the reduction of methoxy- or amino-substituted benzenes to dihydro compounds, which are readily hydrolyzed to cyclo-hexenones. Under mUd acid conditions, the first-formed -unsaturated ketones are obtained, but these are readily isomerized to the conjugated a, -unsaturated compounds (7.46). This is an excellent method for preparing substituted cyclo-hexenones. 

The resulting aza-enolate reacts like a ketone enolate with Su2-reactive alkylating agents— here, benzyl chloride—to form the new carbon—carbon bond and to re-form the imine. The alkylated imine is usually hydrolysed by the mUd acidic work-up to give the alkylated... 

Acids commonly used in sandstone formations include hydrofluoric-based acids. Full strength mud acid (12wt% HCl + 3wt% HF) has been used to stimulate sandstone reservoirs for several decades [J]. Beeause of the fast reaction of hydrofluoric acid with clay minerals, various retarded mud acids were introduced. In one system, aluminum ehloride was added to mud acid systems to ensure deep acid penetration [4. In a seeond system, boric acid was used to achieve the same goal [5]. Reeently, LuUo and Rae [6] introduced a new acid system, consisting of phosphonic acid and hydrofluoric acid. For high temperature applications, mixtures of organic acids (formic or acetic) and hydrofluoric acids are used [7]. 

Combined Effect of Acids and Salts. The effect of simple inorganic salts, which are commonly encountered in acid stimulation processes, was examined [54]. Sodium and calcium chlorides are present in almost all formation brines. Potassium and ammonium chlorides are used in sandstone reservoirs as temporary clay stabilizers [96, 97]. Aluminum chloride is used in some mud acid formulations to retard hydrofluoric acid for deep acid penetration [4]. 

Sindhu et al. (2014) compared the ability of three bacterial strains (Bacillus firmus Nil 0830, B. sphaericus Nil 0838, and Paracoccus denitrificans) to accumulate P(3HB) using a rice straw hydrolysate as carbon source. This mUd acid pretreated hydrolysate contained 23 g of xylose and 4.9 g of acetic acid, together with much lower concentrations of glucose, arabinose, formic acid, furfural, and hydroxyl-methyl-furfural. They selected B. firmus Nil 0830 as this strain produced higher amounts of P(3HB) using the hydrolysate without any detoxifying step (Sindhu et al. 2014). 

Dowell did introduce a mixture of 12% HCl-3% HF, called mud acid, in 1939. The purpose of this mud add was to remove drilling-mud filter cake from the wellbore. However, use was limited to wellbore treatment only. Successful treatments were pumped in the Gulf Coast area. ... 

COj-enhanced HF treatment is a method that involves the displacement of oil near the wellhore with a gas, preferably CO, prior to acidizing This method, developed hy Amoco, was based on the observation by Gidley that gas wells and oil wells respond differently to the amount of mud add used in treatment. With gas wells, the stimulation response was found to be in proportion to the amount of mud acid used. However, with oil wells, the response reached a maximum at a specific volume of about 75 gal/ft. 

The volumes of preflush and 12-3 (12% HCl-3% HF regular strength) mud add can be varied. Of course, 12-3 mud acid is not required other HF mixtures may be used. In any case, CO is injected with acid. This reduces the density of acidizing fluids. The addition of CO to acid stages also... 

Fogler, H. S., K. Lund, and C. C. McCune. 1973. Dissolution of selected minerals in mud acid. Paper 52C, presented at the American Institute of Chemical Engineers 74th National Meeting, New Orleans. Fogler,... 

In a model synthetic study that focused on the CD-D fragment of angelmicin B (548), Narayan and Roush reported that furan 173 reacted readily with the transient benzyne derived from tribromide 541 (Scheme 13.109) [173]. Upon mUd acid workup, a mixture (1 1) of regioisomers 542 and 543 was produced, although each was found to be very air sensitive. Reaction of the mixture with NaH, BnBr, and TBAF provided 544 in 75% yield. Deprotection and CAN mediated oxidation afforded quinone 545. A palladium-catalyzed cross-coupling of boronic acid 546 and 545 then... 

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