Hydriodic acid #CAS10034-85-2

Hydriodic acid #CAS10034-85-2

Hydrogen iodide in aqueous solution is called hydroiodic acid, a strong acid. Its chemical formula is HI. Its molecular weight is 127.91. It is a colorless gas, pale yellow liquid, or solid clumps. It has a strong, pungent odor. Its melting point is -50.8℃, boiling point is -35.38℃, relative density is 5.660 (gas), 2.85-4.7 (liquid), and refractive index is 1.46616. In air, it reacts with water vapor to form a white acidic fumes. It is extremely soluble in water, releasing a large amount of heat to form hydroiodic acid. It is slightly soluble in ethanol. It is unstable and decomposes into iodine and hydrogen gas upon heating and exposure to light. It decomposes significantly above 300℃. Its azeotropic solution is a colorless or pale yellow fuming liquid with a boiling point of 127℃ and a relative density of 1.7015. It is a strong acid (the degree of dissociation in a 0.1 mol·L⁻¹ hydroiodic acid solution can reach 95%). Hydrogen iodide is much less soluble in organic solvents than in water, exhibiting characteristics of a non-electrolyte or a weak electrolyte. Its ionization constant in pyridine is 3 × 10⁻³. It readily decomposes into iodine and hydrogen in air. It has strong reducing properties, being the most potent reducing agent among hydrohalic acids, and can be oxidized by Cl₂, Br₂, and concentrated sulfuric acid to release iodine. It is oxidized by air at room temperature and can be oxidized by concentrated nitric acid and concentrated sulfuric acid. It reacts with most metals to produce the corresponding iodides and hydrogen gas.

Application of Hydriodic acid 

1. Used for producing organic iodide. As general reagents and pharmaceutical intermediates.
2. Used as the analysis reagents, also used in the preparation of the iodide.
3. Used as a reducing agent, also used in the synthesis of alkyl iodine and other alkyl iodide.
4. Used for Determination of methoxy, ethoxy and selenium, dissolution of acid-insoluble inorganic substance, such as an alkaline earth metal sulfate and mercury iodide and so on. Used as a reducing agent. Used for the preparation of iodide.
5. Used for Determination of methoxy, dissolution of acid-insoluble (especially hot) inorganic substance, such as an alkaline earth metal sulfate and mercury iodide and so on. Used as a reducing agent.

Application of DL-Proline

1. Application of amino acid drugs in the pharmaceutical industry. One of the raw materials for compound amino acid large-volume parenteral solutions. Used for malnutrition, protein deficiency, severe gastrointestinal diseases, and protein supplementation after burns and surgery. No obvious toxic side effects. 2. Enhancing plant cold resistance. Proline (Pro) is a component of plant proteins and can exist widely in a free state within plants. Under stress conditions such as drought and salinity, many plants accumulate large amounts of proline. Besides acting as an osmotic regulator in plant cytoplasm, accumulated proline plays an important role in stabilizing the structure of biological macromolecules, reducing cell acidity, detoxifying ammonia, and regulating cellular redox potential as an energy reservoir. Under adverse conditions (drought, salinity, heat, cold, freezing), the proline content in plants increases significantly. The proline content in plants reflects their stress resistance to a certain extent; drought-resistant varieties often accumulate more proline. Therefore, measuring proline content can be used as a physiological indicator for drought-resistant breeding. In addition, due to its strong hydrophilicity, proline can stabilize protoplasmic colloids and metabolic processes within tissues, thus lowering the freezing point and preventing cell dehydration. Under low-temperature conditions, the increase of proline in plant tissues can improve the plant's cold resistance, and therefore can also be used as a physiological indicator for cold-resistant breeding. 3. In vivo effects: In organisms, proline is not only an ideal osmotic regulator, but also a protective substance for membranes and enzymes, as well as a free radical scavenger, thus protecting plant growth under osmotic stress. Proline can also regulate cytoplasmic osmotic balance regarding the accumulation of potassium ions in vacuoles, another important osmotic regulator in organisms. 4. Industrial applications: In the synthetic industry, proline can participate in inducing asymmetric reactions and can be used as a catalyst for hydrogenation, polymerization, and aqueous reactions. When used as a catalyst for these reactions, it has the characteristics of high activity and good stereospecificity. 5. Other applications: 5.1 Proline and its derivatives are often used as symmetric catalysts in organic reactions. The reduction of CBS and the catalytic aldol condensation reaction catalyzed by proline are prominent examples. 5.2 During brewing, proteins rich in proline bound to polyphenols can produce haze (turbidity). 5.3 Raw materials for the synthesis of cholesterol ester inhibitors. 5.4 Flavoring agents: when heated with sugar, an amino-hydroxyl group reaction occurs, producing substances with a special aroma.