Solubility water in oxide

Water is supplied in large excess in order to favour propylene glycol production. The reaction is catalysed by sulfuric acid and takes place at room temperature. In order to dilute the feed and to keep the propylene oxide soluble in water, methanol is also added. The reaction is carried out in a 5-litre stirred-jacketed glass reactor. Initial conditions described by Furusawa et al. (1969) have been applied an equivolumic feed mixture of propylene oxide and methanol is added to the reactor initially supplied by water and sulfuric acid, for a propylene oxide concentration of 2,15 mol/L. In agreement with previous works reported in literature, kinetic parameters of the reaction modelled by an Arrhenius law are summarised in table 1. 

Isobutyric acid, dimethylacetic acid, 2-methylpropanoic acid, (CHjjjCH COOH, colourless syrupy liquid with an unpleasant odour b.p. 154°C. Prepared by oxidation of 2-methylpropanol with K2Cr207 and H2SO4. Salts soluble in water. Used in alkaline solution for sweetening gasoline. 

Colourless crystals m.p. I25°C, soluble in water and alcohol. In aqueous solution forms equilibrium with its lactones. Gluconic acid is made by the oxidation of glucose by halogens, by electrolysis, by various moulds or by bacteria of the Acetobacter groups. 

IH2O. Prepared from Fe and I2. Soluble in water, oxidized to I2 and Fe(III) derivatives in air. 

CfiHi 05 0 C6H4 CH20H. Colourless, bitter crystals, m.p. 20 PC soluble in water and alcohol, insoluble in chloroform. It occurs in the leaves, bark and twigs of species of willow and poplar. On oxidation with dilute nitric acid it is converted into helicin, the glucoside of salicylaldehyde, which has been made the starting point of further syntheses. Gives populin with benzoyl chloride. 

Racemic acid, ( )-tartaric acid, is a compound of the two active forms. M.p. 273 C (with IHjO), m.p. 205°C (anhydrous). Less soluble in water than (-t-)-tartaric acid. Formed, together with mesotartaric acid, by boiling (4-)-tartaric acid with 30% NaOH solution, or by oxidation of fumaric acid. Potassium hydrogen racemate is very insoluble. 

Mesotartaric acid crystallizes in plates (IHjO), m.p. 140 C (anhydrous). Very soluble in water. Obtained from the mother-liquors in the preparation of racemic acid or by oxidation of maleic acid. Potassium hydrogen mesotartrale is soluble in water. 

Boron trioxide is not particularly soluble in water but it slowly dissolves to form both dioxo(HB02)(meta) and trioxo(H3B03) (ortho) boric acids. It is a dimorphous oxide and exists as either a glassy or a crystalline solid. Boron trioxide is an acidic oxide and combines with metal oxides and hydroxides to form borates, some of which have characteristic colours—a fact utilised in analysis as the "borax bead test , cf alumina p. 150. Boric acid. H3BO3. properly called trioxoboric acid, may be prepared by adding excess hydrochloric or sulphuric acid to a hot saturated solution of borax, sodium heptaoxotetraborate, Na2B407, when the only moderately soluble boric acid separates as white flaky crystals on cooling. Boric acid is a very weak monobasic acid it is, in fact, a Lewis acid since its acidity is due to an initial acceptance of a lone pair of electrons from water rather than direct proton donation as in the case of Lowry-Bronsted acids, i.e. 

The azides are salts which resemble the chlorides in solubility behaviour, for example silver azide, AgNj, is insoluble and sodium azide, NaN3, soluble in water. Sodium azide is prepared by passing dinitrogen oxide over molten sodamide ... 

Arsenic(III) oxide is slightly soluble in water, giving a solution with a sweetish taste—but as little as 0.1 g can be a fatal dose (The antidote is freshly-precipitated iron(III) hydroxide.) The solution has an acid reaction to litmus, due to the formation of arsenic(III) acid ... 

Nitrates are prepared by the action of nitric acid on a metal or its oxide, hydroxide or carbonate. All nitrates are soluble in water. On heating, the nitrates of the alkali metals yield only oxygen and the nitrite ... 

These can be prepared by electrolytic oxidation of chlorates(V) or by neutralisation of the acid with metals. Many chlorates(VII) are very soluble in water and indeed barium and magnesium chlorates-(VII) form hydrates of such low vapour pressure that they can be used as desiccants. The chlorate(VII) ion shows the least tendency of any negative ion to behave as a ligand, i.e. to form complexes with cations, and hence solutions of chlorates (VII) are used when it is desired to avoid complex formation in solution. 

When an element has more than one oxidation state the lower halides tend to be ionic whilst the higher ones are covalent—the anhydrous chlorides of lead are a good example, for whilst leadfll) chloride, PbCl2, is a white non-volatile solid, soluble in water without hydrolysis, leadflV) chloride, PbC, is a liquid at room temperature (p. 200) and is immediately hydrolysed. This change of bonding with oxidation state follows from the rules given on p.49... 

Chromium(VI) oxide is very soluble in water initially, chromic acid , H2Cr04, may be formed, but this has not been isolated. If it dissociates thus ... 

The chromates of the alkali metals and of magnesium and calcium are soluble in water the other chromates are insoluble. The chromate ion is yellow, but some insoluble chromates are red (for example silver chromate, Ag2Cr04). Chromates are often isomorph-ous with sulphates, which suggests that the chromate ion, CrO has a tetrahedral structure similar to that of the sulphate ion, SO4 Chromates may be prepared by oxidising chromium(III) salts the oxidation can be carried out by fusion with sodium peroxide, or by adding sodium peroxide to a solution of the chromium(IIl) salt. The use of sodium peroxide ensures an alkaline solution otherwise, under acid conditions, the chromate ion is converted into the orange-coloured dichromate ion ... 

Like all nitrates, it is soluble in water on heating it decomposes evolving nitrogen dioxide and oxygen, but leaving the metal, and not, as is usual with other nitrates, the oxide ... 

Saccharic acid. Use the filtrate A) from the above oxidation of lactose or, alternatively, employ the product obtained by evaporating 10 g. of glucose with 100 ml. of nitric acid, sp. gr. 1 15, until a syrupy residue remains and then dissolving in 30 ml. of water. Exactly neutralise at the boiling point with a concentrated solution of potassium carbonate, acidify with acetic acid, and concentrate again to a thick syrup. Upon the addition of 50 per cent, acetic acid, acid potassium saccharate sepa rates out. Filter at the pump and recrystaUise from a small quantity of hot water to remove the attendant oxahc acid. It is necessary to isolate the saccharic acid as the acid potassium salt since the acid is very soluble in water. The purity may be confirmed by conversion into the silver salt (Section 111,103) and determination of the silver content by ignition. 

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