Quaternary ammonium salt polymers

Both in situ cross-linking of partially hydroly2ed polyacrylamides (69) and injection of quaternary ammonium salt polymers having long hydrophilic side chains (70) have been used to reduce the permeabiUty of water-producing 2ones adjacent to production wells. This permeabiUty reduction decreases the produced water oil ratio as does injection of polyacrylamide in high hardness brine to reduce permeabiUty (71). 

The substantial decrease of polyacrylamide solution viscosity in mildly saline waters can be uti1i2ed to increase injection rates. A quaternary ammonium salt polymer can be added to the polyacrylamide solution to function as a salt and reduce solution viscosity (144). If the cationic charge is in the polymer backbone and substantially shielded from the polyacrylamide by steric hindrance, formation of an insoluble interpolymer complex can be delayed long enough to complete polyacrylamide injection. Upon contacting formation surfaces, the quaternary ammonium salt polymer is adsorbed reducing... 

Quaternary ammonium salt polymers are more versatile and have been used in drilling fluids, completion fluids, acidizing treatments, and hydraulic fracturing. No well shut-in period is required. 

By using a clay stabilizing quaternary ammonium salt polymer, formation damage associated with low salinity polyacrylamide solvents can be reduced (348). 

More recently certain quaternary ammonium salt polymers have been claimed to be effective in substantially reducing fine particle migration even in the absence of water-swelling clays (1). However, there is little information readily available concerning... 

TABLE III. EFFECTIVENESS OF QUATERNARY AMMONIUM SALT POLYMERS AS SWELLING CLAY STABILIZERS3... 

The effectiveness of nonionic polymers as migrating clay stabilizers and the geometry of the adsorbed polymer - mineral complex may be substantially different for the nonionic polymers and the quaternary ammonium salt polymers. The observation that some quaternary ammonium salt polymers, while effective swelling clay stabilizers, are ineffective mineral fines stabilizers is consistent with a different adsorbed polymer - particle complex geometry on different mineral surfaces. 

The first set of data is for oil production from 22 wells. A quaternary ammonium salt polymer clay stabilizer was utilized in five of the well treatments. Otherwise the 22 well treatment designs were identical. Use of the clay stabilizer in 5 well treatments resulted in a 131% production increase compared to a 156% increase after stimulation of 17 wells without clay stabilizer. Although the initial overall production response of the five clay stabilizer treated wells was less, the overall production decline rate was 4% per year compared to 16%/yr for the treatments which did not include the clay stabilizing polymer. This decline rate was determined for the period 4 to 24 months after well treatment. It is tempting to speculate that the lower initial production response of the five polymer treated wells was due to the formation of an adsorbed polymer layer which reduced formation permeability (particularly of the Wilcox Formation) significantly. 

Results indicate that the effectiveness of quaternary ammonium salt polymers in stabilizing swelling clays and mineral fine particles is dependent on monomer chemical structure and polymer molecular weight. Long flexible pendant sidechains containing quaternary nitrogen atoms appear to be required for these polymers to function as mineral fine particle stabilizers. 

The results of two field experiments involving a statistically significant number of wells indicated that quaternary ammonium salt polymers can function well as swelling clay and mineral fine particle stabilizers under actual field conditions. 

The reactions are catalyzed by tertiary amines, quaternary ammonium salts, metal salts, and basic ion-exchange resins. The products are difficult to purify and generally contain low concentrations of acryhc acid and some diester which should be kept to a minimum since its presence leads to product instabihty and to polymer cross-linking. 

Polymer-supported amino alcohols and quaternary ammonium salts catalyze the enan-tioselective addition of dialkylzinc reagents to aldehydes (Table 31). When the quaternary ammonium salt F is used in hexane, it is in the solid state, and it catalyzes the alkylation of benzaldehyde with diethylzinc in good chemical yield and moderate enantioselectivity. On the other hand, when a mixture of dimethylformamide and hexane is used as solvent, the ammonium salt is soluble and no enantioselectivity is observed21. 

Transformations to polymer-bound amino compounds, which are often useful as ligands for metals ions or other free species (67), employ a wide selection of organic reactions. Quaternary ammonium salts result from heating isolated polymer tosylate with tertiary amine they may also be prepared in one step from (hydroxyethyl)polystyrene and toluenesulfonyl chloride and a two-fold excess of amine. 

Secondary amines, such as pyrrolidine, must be alkylated with care too polar a solvent leads to participation of a second nearby polymer-bound alkylant in the formation of a quaternary ammonium salt, along with the desired immobilized trialkyl amine. The exception, as seen above, is diisopropylamine, which refuses to displace tosylate even in the refluxing pure amine, or in hot dimethyl-formamide or other polar solvent, while metal diisopropylamide is notorious as a powerful non-nucleophilic base. However, carboxamide is not difficult to form from (carboxymethyl)polystyrene, again using toluenesulfonyl chloride as condensing agent this can then be reduced to (diisopropyl-ethylaminoethyl)polystyrene, which is of interest as a polymer-bound non-nucleophilic base. ... 

In contrast with the reactions involving sulphide or hydrogen sulphide anions, aryl alkyl thioethers and unsymmetrical dialkyl thioethers (Table 4.3) are obtained conveniently by the analogous nucleophilic substitution reactions between haloalkanes and aryl or alkylthiols under mildly basic conditions in the presence of a quaternary ammonium salt [9-15] or polymer-supported quaternary ammonium salt [16]. Dimethyl carbonate is a very effective agent in the formation of methyl thioethers (4.1.4.B) [17]. 

In a manner analogous to that used for the formation of 5-alkyl thioacetates using a polymer-supported quaternary ammonium salt (4.1.31), the dithiocarbamate anion can be 5-alkylated under mild conditions [3]. The corresponding arylation reaction with activated aryl systems requires more vigorous conditions ... 

In the main, the original extractive alkylation procedures of the late 1960s, which used stoichiometric amounts of the quaternary ammonium salt, have now been superseded by solid-liquid phase-transfer catalytic processes [e.g. 9-13]. Combined soliddiquid phase-transfer catalysis and microwave irradiation [e.g. 14-17], or ultrasound [13], reduces reaction times while retaining the high yields. Polymer-supported catalysts have also been used [e.g. 18] and it has been noted that not only are such reactions slower but the order in which the reagents are added is important in order to promote diffusion into the polymer. 

The use of polymer-supported quaternary ammonium salts to catalyse the Wadsworth-Emmons reaction produces acceptable yields from both aromatic and aliphatic aldehydes and ketones [16]. 

Several conclusions can be reached from these data. The first is that on a per mole basis, the quaternary ammonium salt is the most favorable catalyst for this reaction. Among the other compounds, the catalytic activity of 1.5 mole-% of crown, PEG, or PEG-MME are similar. If equal weights of PEG-400 and PEG-3400 are used, quite different reaction rates are observed. This is because each polymer chain is capable of transporting one cation across the phase boundary at a time. The ratio of molecular weights is 8.5, so there are 8.5 more catalysts available in the PEG-400 catalyzed reaction than in the one involving the higher molecular weight compound. The actual ratio of rates for these two processes is 12.5, or nearly the expected value. 

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