Compounds quaternary

The hydrogenation of alkyl, aryl, or aralkylpyridinium salts is a moderately uncomplicated means of obtaining A-substituted piperidines. The quaternary salts reduce more readily than the salts of the parent pyridines (10) and yield of -substituted piperidines is usually better than obtained by reaction of the piperidine with the appropriate halide. The reduction may be carried out under a variety of conditions of pressure and temperature, in the presence or absence of base, in water, alcohol, or acetic acid. Raney nickel, palladium on a carrier, rhodium on a carrier and platinum oxide have all been used, with platinum oxide enjoying the widest use. 

The hydrogenation of the methiodide of ethyl nicotinate in alcohol in the presence of Raney nickel and triethylamine, at 120° and 120 atm for eight hours gave over 80 % of ethyl-1 -methylpiperidine-3-carboxylate (106). When the reduction was run for 4 hr at 80° and the same pressure, 54% of the hexahydro compound and 38% of a tetrahydro product were obtained. 

The formation of derivatives from quaternary compounds containing an ester function could take place in the following manner  

Uptake of the first molar equivalent of hydrogen gives the bracketed intermediate. Although the 5,6-double bond is in conjugation with the 3,4-bond it is a much weaker system than that of the 3,4-bond and the carbonyl system. It could be expected that the 5,6-bond would be preferentially attacked as if it were an isolated double bond. 

4-Addition of hydrogen followed by migration of the 2,3-double bond would also give the same intermediate shown above. However, since the 4-position is occupied, 1,2-addition of hydrogen seems more logical. 

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Figure C2.16.3. A plot of tire energy gap and lattice constant for tire most common III-V compound semiconductors. All tire materials shown have cubic (zincblende) stmcture. Elemental semiconductors. Si and Ge, are included for comparison. The lines connecting binary semiconductors indicate possible ternary compounds witli direct gaps. Dashed lines near GaP represent indirect gap regions. The line from InP to a point marked represents tire quaternary compound InGaAsP, lattice matched to InP.

Two of the material systems shown in figure G2.16.3 are of particular importance. These are the ternary compounds fonned from group III elements such as A1 and Ga in combination with As and quaternary compounds fonned from Ga and In in combination with As and P [8,15,]. Ternary Al Ga s grown on GaAs is the best known of the general class of compounds Quaternary Ga In As grown on InP is... 

Quaternary Ga In j.As jPj, grown on InP is of major importance to fibre-optic communications. In quaternary compounds, both the gap and the lattice constant can be tailored by changing the chemical composition. In thick layers, in order to avoid the generation of strain-induced defects, care must be taken in adjusting the ratio of x and v to maintain the lattice-matched composition x = 2.2v. The available gaps range from 1.34 eV in InP to -0.75 eV in... 

Quantum well lasers ia this system typically use ternary Iuq 53GaQ 47AS wells and biaary InP barriers. AH quaternary lasers, ie, lasers ia which both the wells and barriers are formed by quaternary compounds, are also being developed. These stmctures can be lattice matched or strained. 

Phosphoms trichloride is also used in the manufacture of antifoam agents, catalysts, dyes and pigments, as well as pharmaceutical and quaternary compounds, and is commonly used as a chlorinating agent. Phosphoms trichloride is used to make phosphoms oxychloride, which is used in the manufacture of adsorbents for air filters, antifoam agents, dyes and pigments, mineral-processing materials, pharmaceuticals (qv), and solvents. These uses represented 32,000 t of PCl in 1988 and 30,000 t in 1994. 

Physical Properties. Most quaternary compounds are soHd materials that have indefinite melting poiats and decompose on heating. Physical properties are determined by the chemical stmcture of the quaternary ammonium compound as well as any additives such as solvents. The simplest quaternary ammonium compound, tetramethylammonium chloride [75-57-0] is very soluble ia water (163) and iasoluble ia nonpolar solvents. As the molecular weight of the quaternary compound iacreases, solubiUty ia polar solvents decreases and solubiUty ia nonpolar solvents iacreases (164—166). For example, trimethyloctadecylammonium chloride [112-03-8] is soluble ia water up to whereas dimethyldioctadecylammonium chloride [107-64-2] has... 

The abihty to form aqueous dispersions is a property that gives many quaternary compounds useful appHcations. Placement of polar groups, eg, hydroxy or ethyl ether, ia the quaternary stmcture can iacrease solubiUty ia polar solvents. 

Higher order aUphatic quaternary compounds, where one of the alkyl groups contains - 10 carbon atoms, exhibit surface-active properties (167). These compounds compose a subclass of a more general class of compounds known as cationic surfactants (qv). These have physical properties such as substantivity and aggregation ia polar media (168) that give rise to many practical appHcations. In some cases the ammonium compounds are referred to as iaverse soaps because the charge on the organic portion of the molecule is cationic rather than anionic. 

Mass spectral analysis of quaternary ammonium compounds can be achieved by fast-atom bombardment (fab) ms (189,190). This technique rehes on bombarding a solution of the molecule, usually in glycerol [56-81-5] or y -nitroben2yl alcohol [619-25-0], with argon and detecting the parent cation plus a proton (MH ). A more recent technique has been reported (191), in which information on the stmcture of the quaternary compounds is obtained indirectly through cluster-ion formation detected via Hquid secondary ion mass spectrometry (Isims) experiments. 

There are two reasons why the concentration of quaternaries is beheved to remain at a low level in sewage treatment systems. First, quaternaries appear to bind anionic compounds and thus are effectively removed from wastewater by producing stable, lower toxicity compounds (205). Anionic compounds are present in sewer systems at significantly higher concentrations than are cations (202). Second, the nature of how most quaternaries are used ensures that their concentrations in wastewater treatment systems are always relatively low but steady. Consumer products such as fabric softeners, hair conditioners, and disinfectants contain only a small amount of quaternary compounds. This material is then diluted with large volumes of water during use. 

CgH5)4Bi02CCF2 have been employed (32). There seems to be no marked advantage of the quaternary compounds over the more stable and more easily prepared compounds of the type Ar2BiY2-... 

The solubihty characteristics of sodium acyl isethionates allow them to be used in synthetic detergent (syndet) bars. Complex blends of an isethionate and various soaps, free fatty acids, and small amounts of other surfactants reportedly are essentially nonirritant skin cleansers (66). As a rule, the more detersive surfactants, for example alkyl sulfates, a-olefin sulfonates, and alkylaryl sulfonates, are used in limited amounts in skin cleansers. Most skin cleansers are compounded to leave an emollient residue on the skin after rinsing with water. Free fatty acids, alkyl betaines, and some compatible cationic or quaternary compounds have been found to be especially useful. A mildly acidic environment on the skin helps control the growth of resident microbial species. Detergent-based skin cleansers can be formulated with abrasives to remove scaly or hard-to-remove materials from the skin. 

Bis(pyridiniumthio)quaternary compounds gastric acid secretion and, 2, 519 Bis(selenadiazoles) decomposition, 6, 349... 

According to Nyman the pharmacological action of hyoscine is considerably modified in the quaternary compounds of the alkaloid, e.g., the inhibiting action on salivary secretion is greatly increased in the methonitrate, as is also the spasmolytic activity, but the mydriatic action is unchanged and the central sedative activity disappears. 

The general principle that activation of para substitution is greater than of ortho substitution holds true also for an azinium moiety in the one instance studied. Thus, the activation energy for the 4-chloropyridine quaternary salt 280 (Table II, line 9) is 1 kcal lower than that for the 2-isomer (line 5). The rate relation (2- > 4-isomer) is controlled by the entropies of activation in this reaction due to electrostatic attraction in the transition state (281). The reverse rate relation (4- > 2-position) is predicted for aminations of such quaternary compounds due to electrostatic repulsion (282) plus the difference in E. A kinetic study of the 2- and 4-pyridine quaternary salts... 

Specific alterations of the relative reactivity due to hydrogen bonding in the transition state or to a cyclic transition state or to electrostatic attraction in quaternary compounds or protonated azines are included below (cf. also Sections II, B, 3 II, B, 5 II, C and II, F). A-Protonation is often reflected in an increase in JS and therefore the relative reactivity can vary with the significance of JS in controlling the reaction rate. Variation can also result from rate determination by the second stage of the SjjAr2 mechanism or from the intervention of thermodynamic control of product formation. Variation in the rate and in the reactivity pattern of polyazanaph-thalenes will result when nucleophilic substitution [Eq. (10)] occurs only on a covalent adduct (408) of the substrate rather than on its aromatic form (400). This covalent addition is prevented by any 4-... 

Reaction with dimethylethylamine instead of methylethylamine leads directly to a quaternary compound, which type of compound can also be obtained by reacting the tertiary aminoethyl ether with reactive esters. 

Ether carboxylates are used not only in powdered detergents but in liquid laundry detergents for their hard water stability, lime soap dispersibility, and electrolyte stability they improve the suspension stability and rheology of the electrolyte builder [130,131]. Formulations based particularly on lauryl ether carboxylate + 4.5 EO combined with fatty acid salt and other anionic surfactants are described [132], sometimes in combination with quaternary compounds as softeners [133,163]. Ether carboxylates show improved cleaning properties as suds-controlling agents in formulations with ethoxylated alkylphenol or fatty alcohol, alkyl phosphate esters or alkoxylate phosphate esters, and water-soluble builders [134]. 

The use of alkyl ether carboxylates in manual dishwashing agents was described in 1966 [136]. Subsequently several patents mention combinations of alkyl ether carboxylates with aminoxides [137,142], betaines [138,139,142], different anionic surfactants [140], quaternary compounds [141], alkylpolyglucoside [142], and polyhydroxy fatty acid amide [143]. In all cases the ether carboxylates are used to improve mildness and to achieve good cleaning and lathering properties. 

Quaternary Compounds Low foaming types introduced. Not halogenated and fast acting bactericide... 

The overall advantage of quaternary compounds is that their dosages are very low 1-2 ppm per week only, where we see that Baquacil, although a good bactericide, must be dosed in such a way that we obtain about 100 ppm to kill the algae and some 40 ppm of hydrogen peroxide (H2O2). 

Calcium and magnesium reduce the toxicity of quaternary compounds by competing with them for acidic sites. 

Improved coverage of immature fibres, increased exhaustion but decreased fastness unless further treated with fibre-reactive quaternary compound... 

On 100% acrylic materials the quaternary ammonium retarders are used almost exclusively. Other types have been evaluated, however. For example, saturated alkylamines (RNH2 R = C10, C12, C14 and C16 hydrophobes) were found to be just as effective as the quaternary types although other factors, such as aqueous solubility at the optimal dyebath pH and resistance to subsequent discoloration, favour the quaternary compounds [34]- On the other hand, bis (hydroxyethyl) coco amine (12.10) had relatively little effect and the amphoteric carboxymethyldimethylcocoamine (12.11) none at all, although dimethyl-cocoamine oxide (12.12) was quite an effective retarder [34]- Other cationic compounds used [43,44] have included alkylpyridinium salts, imidazoles and imidazolinium salts, alkyldiamines, alkylpolyamines, as well as sulphonium and phosphonium derivatives. 

The less important positive CCAs are metal-free cationic molecules, such as the black dye nigrosine and the colorless quaternary compound cetyl pyridinium chloride.35,36... 

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