Additive solubility

Although p oly (a-olefin) s (PAO) and esters are the prominent synthetic base stocks for automotive appfications, combinations of the two are becoming the choice in offering a balance of properties such as additive solubility, sludge control, and elastomer compatibility (34). 

Example Concentration of additive Solubility at ambient temperature Solubility at processing temperature Expected effect... 

Biochemical and molecular cloning studies indicate the existence of nine separate and unique forms of adenylyl cyclase (AC), which comprise a distinct enzyme family, referred to as AC1-AC9 [1, 2]. These members of the adenylyl cyclase superfamily are all membrane-bound. There is also an additional soluble form, sAC, that has catalytic activity similar to the others but is genetically the most divergent member of the family. All the membrane-bound forms of adenylyl cyclase are activated by the stimulatory G protein Gas (see Ch. 19), and all with the exception of AC9 are stimulated by forskolin. The soluble form sAC is not stimulated by either Gas or forskolin but is sensitive to bicarbonate levels. All known forms of... 

Morehouse 200 wet mill (Morehouse Industries, Fullerton, CA), operated at 3600 rpm. The finely dispersed slurry was filtered through a 230-mesh vibrating screen to remove the coarse fiber fraction. The residue was washed a second time with 0.02% NaOH for 1 hr and passed through the wet mill and screen to remove additional solubles ... 

Thus, N-pyrimidine phthalimide reacted with hexylamine at room temperature to form an amide-amide. The initial amide-amide formation proceeded more rapidly in chloroform as compared to dimethylsulfoxide (DM SO). However, the ring closure reaction to the imide was favored by the more polar, aprotic DMSO solvent, yielding the imide in nearly quantitative yield after 3 hours at 75 °C. The authors were able to utilize this synthetic approach to prepare well-defined segmented poly(imide-siloxane) block copolymers. It appears that transimidi-zation reactions are a viable approach to preparing polyimides, given that the final polyimide has a Tg sufficiently low to allow extended excursions above the Tg to facilitate reaction without thermal decomposition. Additionally, soluble polyimides can be readily prepared by this approach. Ultimately, high Tg, insoluble polyimides are still only accessable via traditional soluble precursor routes. 

Solubility is a complex matter, and it s not always possible to make correct predictions. In addition, solubilities depend on the concentrations of the reactant ions, and the very words "soluble" and "insoluble" are imprecise. As a rule of thumb, though, a compound is probably soluble if it meets either (or both) of the following criteria ... 

Since the hydroxyl group is present in alcohols and phenols, these compounds are polar. The polarity of the hydroxyl group, coupled with its ability to form hydrogen bonds, enables many alcohols and phenols to mix with water. Since these compounds also contain nonpolar portions, they show additional solubility in many organic solvents, such as dichloromethane and diethyl ether. 

Ether carboxylates are a very versatile class of surfactants, used in diverse applications from mild personal care formulations to lubricants and cutting fluids. They are interrupted soaps, with the addition of a number of ethylene oxide groups between the alkyl chain and the carboxylate group. The additional solubility imparted by the EO groups gives much greater resistance to hardness and reduced irritancy compared to soap. 

Soluble (chlorosilyl)phosphine complexes of Rh(I) can be polymerized into poly(siloxyphosphine) Rh(I) species. In addition, soluble siloxyphosphine-Rh(I) complexes, L3RhCl and L Rh Clj, where L = [(CH3)3SiO]2(CH3)Si(CH2)2PPh2, serve as models for their polymeric counterparts. 

Because soluble tumor necrosis factor alfa receptors are supposedly involved in the macrophage activation syndrome, the authors speculated that the administration of additional soluble receptors may have been the cause of a prolonged and exacerbated syndrome. 

Many proteins, particularly those of eukaryotic origin, require an interacting protein partner for correct folding and stability.190-193 Often, these proteins contain intrinsically disordered domains that mediate the protein interaction. Frequently, proteins with unstructured domains cannot be expressed solubly in E. coli. In some cases, coexpression of the interacting protein has improved the stability and solubility of the protein of interest.194-197 As an example, the yield of inducible nitric oxide synthase (iNOS) was 20—25 times greater when coexpressed with its natural partner, calmodulin, than in the absence of calmodulin. Additionally, soluble iNOS could be isolated when expressed without calmodulin but it was deficient in heme and flavins and almost completely inactive.198 Methods for coexpression in both prokaryotic and eukaryotic hosts have been recently reviewed.1... 

Some properties are more clearly defined than others. For example, solubility is defined as the amount of solid in equilibrium with the solvent. Solubility can affect the capacity of the crystallization process, as well as its ability to reject undesired compounds and minimize loss in the mother liquor. In addition, solubility varies widely from compound to compound or solvent to solvent. On the other hand, there are properties that are much less well characterized or understood. For example, the mechanism and condition for the formation of oil or amorphous solid remain unclear. The composition of oil and amorphous solid can be variable, and certainly can contain a much higher level of impurities than that in the crystalline solid, which leads to a real purification challenge. In addition, oil or amorphous solid generally is less stable and can create critical issues in drug formulation and storage stability. 

There are many works of patent character in which methods of obtaining PETP-fibres stock dyed [275-279] are described. Pigments (black and TiO2) in the form of dispersions and pastes and additives soluble in polymer melt [280] are used for dyeing and stabilization. 

Ester-based base oils have certain inherent properties such as good VI, and therefore no need of VI improver additives, additive solubility, detergency and disper-sancy, an affinity for metal surfaces, and are more biodegradable than mineral oils. 

---