Sulfate reactions

V-Alkylation can also be carried out with the appropriate alkyl haUde or alkyl sulfate. Reaction of aniline with ethylene, in the presence of metallic sodium supported on an inert carrier such as carbon or alumina, at high temperature and pressure yields V/-ethyl- or /V,/V-diethylaniline (11). At pressures below 10 MPa (100 atm), the monosubstituted product predominates. 

Sulfamic acid has a unique combination of properties that makes it particularly well suited for scale removal and chemical cleaning operations, the main commercial appHcations. Sulfamic acid is also used in sulfation reactions, pH adjustment, preparation of synthetic sweeteners (qv), and a variety of chemical processing appHcations. Salts of sulfamic acid are used in electroplating (qv) and electroforrning operations as well as for manufacturing flame retardants (qv) and weed and hnish killers (see Herbicides). 

Table 3. Reagents for Direct Sulfonation and Sulfation Reactions ...

Table 8. Heats of Sulfonation and Sulfation Reactions Using Gaseous SO3 and Oleum Reagents ...

The viscosity of sulfonation and sulfation reaction mixtures increases with conversion, often producing extremely high viscosities. Figure 1 provides temperature—viscosity curves for oleum and SO -detived products. Sulfonation process design must accommodate such viscosities. 

Sulfites. The Hterature concerning dialkyl sulfites is extensive, although less than for sulfates. Reactions involving alkylation are similar to those of sulfates. Sulfites also undergo elimination, transesterification, and isomerization. The last two parallel reactions of phosphites. 

Because Pb, Pb02, and PbSO are all soHds having low solubiHties, the activities of these substances are unity. At 25 °C, the absolute temperature Tis 298.15 K. The value of R, the gas constant, used is 8.3144 J/(molK). E, the Earaday constant, is 96,485 C/mol. The standard ceU voltage for the double sulfate reaction must be known as weU as the activities of sulfuric acid and water at any given concentration or temperature. 

To calculate the open circuit voltage of the lead—acid battery, an accurate value for the standard cell potential, which is consistent with the activity coefficients of sulfuric acid, must also be known. The standard cell potential for the double sulfate reaction is 2.048 V at 25 °C. This value is calculated from the standard electrode potentials for the (Pt)H2 H2S04(yw) PbS04 Pb02(Pt) electrode 1.690 V (14), for the Pb(Hg) PbS04 H2S04(yw) H2(Pt) electrode 0.3526 V (19), and for the Pb Pb2+ Pb(Hg) 0.0057 V (21). 

Lime-Sulfuric. Recovery of citric acid by calcium salt precipitation is shown in Figure 3. Although the chemistry is straightforward, the engineering principles, separation techniques, and unit operations employed result in a complex commercial process. The fermentation broth, which has been separated from the insoluble biomass, is treated with a calcium hydroxide (lime) slurry to precipitate calcium citrate. After sufficient reaction time, the calcium citrate slurry is filtered and the filter cake washed free of soluble impurities. The clean calcium citrate cake is reslurried and acidified with sulfuric acid, converting the calcium citrate to soluble citric acid and insoluble calcium sulfate. Both the calcium citrate and calcium sulfate reactions are generally performed in agitated reaction vessels made of 316 stainless steel and filtered on commercially available filtration equipment. 

Vinylpyrrolidinone—dimethylaminoethyl methacrylate copolymer, dimethyl sulfate reaction product. 

The sulfation reaction has an optimum at a mean bed temperature of around III6K(I550°F). 

The sulfation reaction does not have an optimum reaction temperature under pressurized operating conditions and the higher partial pressure of oxygen results in increased conversion of sulfur dioxide to sulfur trioxide. 

The production of isopropanol from propylene occurs by either a direct hydration reaction (the newer method) or by the older sulfation reaction followed by hydrolysis. 

The sulfation reaction occurs in the liquid phase at approximately 35 °C. An 85 wt% alcohol yield could be realized. The reaction is similar to the sulfation of ethylene or propylene and results in a mixture of sec-butyl hydrogen sulfate and di-sec-butyl sulfate. The mixture is further hydrolyzed to sec-butanol and sulfuric acid ... 

Dimethylpiienylthiourea, 46, 70 Dimethylphosphine, 46, 103 Dimethylphosphimc acid, 46, 103 Dimethylphosphinyl chloride, 46, 103 Dimethyl sulfate, reaction with di-... 

Some alcohols, arylamines, and phenols are sulfated. The sulfate donor in these and other biologic sulfation reactions (eg, sulfation of steroids, glycosaminoglycans, glycolipids, and glycoproteins) is adenosine 3 -phos-phate-S -phosphosulfate (PAPS) (Chapter 24) this compound is called active sulfate. ... 

The sulfation reaction, (D), in Section 9.1.1, is the second step of a process to remove SO, from the flue gas of a coal-fired utility furnace. The first step is the calcination of limestone (CaC03) particles, injected either dry or in an aqueous slurry, to produce CaO ... 

Dimethyl sulfate, reaction with di-methylformamide, 47, 52 Dimethyl sulfoxide, in synthesis of phenyl f-butyl ether, 45, 89 potassium salt, preparation, 48, 109, 110... 

The sulfation reaction has an optimum at a mean bed temperature of around III6 K (1550 F). Units are usually designed to operate at this... 

The immobilized lactose (37 a) was employed in sulfatation reactions using SOs-NEts complex. After mercury(II) trifluoroacetate cleavage, a 2.7 1 mixture of 3 -sulfated lactose and lactose was isolated and separated using anionic exchange resin. 

Reactions (1) and (2) are common for both normal and triple superphosphate. Reaction (3) is important in triple superphosphate because of the lack of large amounts of calcium sulfate. Reaction (5) is important... 

The metal dissolves in nitric and sulfuric acid. The solution on evaporation crystallizes to yield thallous nitrate and sulfate. Reaction with hydrochloric acid is very slow. 

It can be seen, therefore, that on typical paste shrinkage in the region of 4000 microstrain, that some 30-40% of this could be accounted for by the sulfate component. An important point to note is that the sulfate reaction has a negative influence on shrinkage and, therefore, acts as a restraint to creep and shrinkage as the reaction proceeds. It was noted in an earlier section that the addition of a water-reducing admixture delays ettringite reactions and could be a possible mechanism by which the volume deformations are increased. 

After the sulfation of alcohols and phenols was reported to proceed efficiently with DCC/ H2S04, 75 76 Wieland et al. 81 applied this procedure for the sulfation of the tyrosine residue in D-Tyr6-a//-D-retro-antamanide. This contains no reactive group in addition to the phenolic group, and the desired product was obtained in satisfactory yields. Despite these promising initial results, this type of sulfation reaction has been adopted only sporadically, e.g. for sulfation of the CCK-8 derivative Boc-Asp(OtBu)-Tyr-Met-Gly-Trp(For)-Met-Asp-(OtBu)-Phe-NH2 with 70% yield1 2 or for the preparation of an intermediate fragment in the synthesis of CCK-related peptides (Scheme 3). 83 ... 

It should be noted that the sulfation reaction requires the presence of oxygen. This serves to highlight the importance of air/acid gas ratio control in the front end furnace feed and the prevention of oxygen breakthrough into the catalyst beds. This can be of particular importance when oxygen enriched air feed is used in the front end reaction furnace (31). 

---