Production of Sulfuric acid

Sulfuric acid (alternative spelling sulphuric acid), with the cas number 7664-93-9, is a highly corrosive strong mineral acid with the molecular formula H2 SO4. It is a pungent-ethereal, colorless to slightly yellow viscous liquid which is soluble in water at all concentrations. Sometimes, it may be dark brown as dyed during its industrial production process in order to alert people to its hazards.

Pure sulfuric acid is not encountered naturally on Earth in anhydrous form, due to its great affinity for water. Dilute sulfuric acid is a constituent of acid rain, which is formed by atmospheric oxidation of sulfur dioxide in the presence of water – i.e., oxidation of sulfurous acid. Sulfur dioxide is the main byproduct produced when sulfur-containing fuels such as coal or oil are burned.

Although Sulfuric acid is the common starting raw material, other sources of Sulfuric acid (CAS NO.7664-93-9) can be used, including iron, copper, lead, nickel, and zinc sulfides. Hydrogen sulfide, a by-product of petroleum refining and natural gas refining, can be burned to sulfur dioxide. Gypsum (CaSO4) can also be used but needs high temperatures to be converted to sulfur dioxide. Other uses for it include the manufacture of fertilizers, chemicals, inorganic pigments, petroleum refining, etching, as a catalyst in alkylation processes, in electroplating baths, for pickling and other operations in iron and steel production, in rayon and film manufacture, in the making of explosives, and in nonferrous metallurgy.
Preparation of Sulfuric acid: The manufacture of Sulfuric acid (CAS NO.7664-93-9) by the lead chamberprocess involves oxidation of sulfur to sulfur dioxide by oxygen, further oxidation of sulfur dioxide to sulfur trioxide with nitrogen dioxide, and, finally, hydrolysis of sulfur trioxide.

S + O2 → SO2

2NO + O2→ 2NO2

SO2 + NO2 → SO3 + NO

SO3 + H2O → H2SO4

Modifications of the process include towers to recover excess nitrogen oxides and to increase the final acid concentration from 65% (chamber acid) to 78% (tower acid).

The contact process has evolved to become the method of choice for sulfuric acid manufacture because of the ability of the process to produce stronger acid.

S + O2 → SO2

2SO2 + O2 → 2SO3

SO3 + H2O → H2SO4

In the process, sulfur and oxygen are converted to sulfur dioxide at 1000 °C and then cooled to 420 °C. The sulfur dioxide and oxygen enter the converter, which contains a catalyst such as vanadium pentoxide (V2O5). About 60 to 65% of the sulfur dioxide is converted by an exothermic reaction to sulfur trioxide in the first layer with a 2 to 4-second contact time. The gas leaves the converter at 600°C and is cooled to 400°C before it enters the second layer of catalyst. After the third layer, about 95% of the sulfur dioxide is converted into sulfur trioxide. The mixture is then fed to the initial absorption tower, where the sulfur trioxide is hydrated to sulfuric acid after which the gas mixture is reheated to 420 °C and enters the fourth layer of catalyst that gives overall a 99.7% conversion of sulfur dioxide to sulfur trioxide. It is cooled and then fed to the final absorption tower and hydrated to sulfuric acid. The final sulfuric acid concentration is 98 to 99% (1 to 2% water). A small amount of this acid is recycled by adding some water and recirculating into the towers to pick up more sulfur trioxide.

When you are using this chemical, please be cautious about it as the following:

In case of contact with eyes, rinse immediately with plenty of water and seek medical advice;

Never add water to this product;

In case of accident or if you feel unwell, seek medical advice immediately (show label where possible);

Wear suitable protective clothing and gloves;

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Intro to 1,2,3-Propanetriol

Name:1,2,3-Propanetriol

EINECS:200-289-5

Molecular Formula:C3H5(OH)3

CAS Registry Number:56-81-5

Appearance:Clear, colorless, viscous liquid

Molecular Weight:92.09

Density:1.25

Boiling Point:290°C

Melting Point:18°C

Flash Point:160°C

Storage Temperature:2-8°C

Refractive index:1.452-1.475

Solubility:Miscible
Personal protective equipment :

1. Eye/face protection

Safety glasses with side-shields conforming to EN166 Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).

2. Skin protection

Handle with gloves. Gloves must be inspected prior to use. Use proper glove removal technique (without touching glove’s outer surface) to avoid skin contact with this product. Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices. Wash and dry hands.

3. Body Protection

impervious clothing, The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace.

4. Respiratory protection

Where risk assessment shows air-purifying respirators are appropriate use a full-face respirator with multi-purpose combination (US) or type ABEK (EN 14387) respirator cartridges as a backup to engineering controls. If the respirator is the sole means of protection, use a full-face supplied air respirator. Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).

1,2,3-Propanetriol is a trihydric alcohol. It is a clear, viscous liquid, with a sweet taste. It has low volatility and high boiling point because the molecules form strong hydrogen bonds. 1,2,3-propanetriol is hygroscopic, which means that it can pick up and give off water. It might absorb vaporous water from the air up to 50 % of its weight. It is completely miscible with water but insoluble in hydrocarbons. The name glycerine refers to the quality that contains more than 95 % glycerol.

All animal and vegetable fats are esters of 1,2,3-propanetriol and fatty acids, i.e. triglycerides. 1,2,3-propanetriol is recovered through splitting of fats to fatty acids and 1,2,3-propanetriol. It is a by-product in soap manufacturing. The substance is also formed in the production of rape-oil methyl ester (RME), which is a substitute for diesel oil. Since 1949 it has also been produced commercially by synthesis from propene. Propene is chlorinated and hydrolyzed to 1,2,3-propanetriol. A newer method is to oxidize propene or propylene oxide with oxygen or hydrogen peroxide over a catalyst.

The world use of glycerol during 2004 was over 300,000 tonnes. The substance is used in nearly all industrial sectors. The largest single use is in the manufacture of alkyd resins used in e.g. paints. In food industry the substance is used as a solvent, moistening agent and an ingredient in syrups among other things. It also retards crystallization of sugar. In drugs and medicine glycerol or its derivatives are used as an ingredient of many mixtures. In cosmetics 1,2,3-propanetriol is used to keep the skin soft and replace skin moisture. In tobacco processing the substance is sprayed on the tobacco leaves before they are shredded and packed. It helps to retain the moisture and influences the burning rate of the tobacco. The many OH-groups of 1,2,3-propanetriol is used to crosslink the polymer chains in production of flexible polyurethane foams. This use is increasing. 1,2,3-Propanetriol is used as lubricant in production of food, drugs and cosmetics as well as for lubricating pumps and bearings exposed to gasoline and benzene. Such fluids would dissolve oil-type lubricants. Another use is for the production of explosives, nitroglycerine.

In Sweden pure 1,2,3-propanetriol is mainly used in food production and in hygienic and cosmetic products. It is also a part of many lubricants, de-icing agents and is used as heat transmission agent. It is an approved food additive with the denotation E422.

Calcium carbonate in nature

Calcium carbonate, with the cas register number 471-34-1, also can be called Carbonic acid calcium salt ; Marble ; and Limestone. Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural lime, and is usually the principal cause of hard water.

Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural lime, and is created when Ca ions in hard water react with carbonate ions creating limescale. It is commonly used medicinally as a calcium supplement or as an antacid, but excessive consumption can be hazardous.

1. Occurrence

1)Geological sources

Calcite, aragonite and vaterite are pure calcium carbonate minerals. Industrially important source rocks which are predominantly calcium carbonate include limestone, chalk, marble and travertine.

2)Biological sources

Eggshells, snail shells and most seashells are predominantly calcium carbonate and can be used as industrial sources of that chemical.  Oyster shells have enjoyed recent recognition as a source of dietary calcium, but are also a practical industrial source. While not practical as an industrial source, dark green vegetables such as Broccoli and Kale contain dietarily significant amounts of calcium carbonate.

2. Preparation of Calcium carbonate

The vast majority of calcium carbonate used in industry is extracted by mining or quarrying. Pure calcium carbonate (e.g. for food or pharmaceutical use), can be produced from a pure quarried source (usually marble).Alternatively, calcium carbonate is prepared from calcium oxide. Water is added to give calcium hydroxide, and carbon dioxide is passed through this solution to precipitate the desired calcium carbonate, referred to in the industry as precipitated calcium carbonate (PCC)

CaCO3 → CaO + CO2

CaO + H2O → Ca(OH)2

Ca(OH)2 + CO2 → CaCO3 + H2O

3. Uses of Calcium carbonate

Calcium carbonate is widely used in both its pure and its impure states. As marble chips, it is sold in many sizes as a filler for artificial stone, for the neutralization of acids, and for chicken grit. It is used to produce viscous solutions or dispersions, to impart body, improve consistency, or stabilize emulsions, including suspending and bodying agents, setting agents, jellying agents, bulking agents, stabilizers and thickeners.

When you are using this chemical, please be cautious about it as the following:

In case of contact with eyes, rinse immediately with plenty of water and seek medical advice;

Wear suitable protective clothing, gloves and eye/face protection;

Wear suitable gloves and eye/face protection.

Safety information about Potassium dichromate

Potassium dichromate is a common inorganic chemical reagent, most commonly used as an oxidizing agent in various laboratory and industrial applications. As with all hexavalent chromium compounds, it is acutely and chronically harmful to health and must be handled and disposed of appropriately.

1. Potential Health Effects

1) Inhalation:

Corrosive. Extremely destructive to tissues of the mucous membranes and upper respiratory tract. May cause ulceration and perforation of the nasal septum. Symptoms may include sore throat, coughing, shortness of breath, and labored breathing. May produce pulmonary sensitization or allergic asthma. Higher exposures may cause pulmonary edema.

2) Ingestion:

Corrosive. Swallowing can cause severe burns of the mouth, throat, and stomach, leading to death. Can cause sore throat, vomiting, diarrhea. May cause violent gastroenteritis, peripheral vascular collapse, dizziness, intense thirst, muscle cramps, shock, coma, abnormal bleeding, fever, liver damage and acute renal failure.

3) Skin Contact:

Corrosive. Symptoms of redness, pain, and severe burn can occur. Dusts and strong solutions may cause severe irritation. Contact with broken skin may cause ulcers (chrome sores) and absorption, which may cause systemic poisoning, affecting kidney and liver functions. May cause skin sensitization.

4) Eye Contact:

Corrosive. Contact can cause blurred vision, redness, pain and severe tissue burns. May cause corneal injury or blindness.

5) Chronic Exposure:

Repeated or prolonged exposure can cause ulceration and perforation of the nasal septum, respiratory irritation, liver and kidney damage and ulceration of the skin. Ulcerations at first may be painless, but may penetrate to the bone producing “chrome holes.” Known to be a human carcinogen.

6) Aggravation of Pre-existing Conditions:

Persons with pre-existing skin disorders, asthma, allergies or known sensitization to chromic acid or chromates may be more susceptible to the effects of this material.

2. Exposure Controls/Personal Protection

1) Airborne Exposure Limits:

– OSHA Permissible Exposure Limit (PEL):

For chromic acid and chromates, as CrO3 = 0.1 mg/m3 (ceiling)- ACGIH Threshold Limit Value (TLV):

For water-soluble Cr(VI) compounds, as Cr = 0.05 mg/m3 (TWA), A1 – confirmed human carcinogen.

2) Ventilation System:

A system of local and/or general exhaust is recommended to keep employee exposures below the Airborne Exposure Limits. Local exhaust ventilation is generally preferred because it can control the emissions of the contaminant at its source, preventing dispersion of it into the general work area. Please refer to the ACGIH document, Industrial Ventilation, A Manual of Recommended Practices, most recent edition, for details.

3) Personal Respirators:

If the exposure limit is exceeded, a half-face dust/mist respirator may be worn for up to ten times the exposure limit or the maximum use concentration specified by the appropriate regulatory agency or respirator supplier, whichever is lowest. A full-face piece dust/mist respirator may be worn up to 50 times the exposure limit, or the maximum use concentration specified by the appropriate regulatory agency, or respirator supplier, whichever is lowest. For emergencies or instances where the exposure levels are not known, use a full-facepiece positive-pressure, air-supplied respirator. WARNING: Air-purifying respirators do not protect workers in oxygen-deficient atmospheres.

4) Skin Protection:


Wear impervious protective clothing, including boots, gloves, lab coat, apron or coveralls, as appropriate, to prevent skin contact.

5) Eye Protection:

Use chemical safety goggles and/or full face shield where dusting or splashing of solutions is possible. Maintain eye wash fountain and quick-drench facilities in work area.

3. Stability and Reactivity

Stability: Stable under ordinary conditions of use and storage.

Hazardous Decomposition Products: Burning may produce chrome oxides.

Hazardous Polymerization: Will not occur.

Incompatibilities: Reducing agents, acetone plus sulfuric acid, boron plus silicon, ethylene glycol, iron, hydrazine, and hydroxylamine. Any combustible, organic or other readily oxidizable material (paper, wood, sulfur, aluminum or plastics).

Conditions to Avoid: Heat, incompatibles.

About Potassium dichromate

Potassium dichromate, K2Cr2O7, is a common inorganic chemical reagent, most commonly used as an oxidizing agent in various laboratory and industrial applications. As with all hexavalent chromium compounds, it is acutely and chronically harmful to health and must be handled and disposed of appropriately. It is a crystalline ionic solid with a very bright, red-orange color. It is also known as potassium bichromate; bichromate of potash; dipotassium dichromate; dichromic acid, dipotassium salt; chromic acid, dipotassium salt; and lopezite.

1. Uses

Potassium Dichromate(CAS.NO:7778-50-9) is a yellow chemical indicator used for identifying concentrations of chloride ions in a salt solution with silver nitrate. It is used as an oxidizing agent in various laboratory and industrial applications. It is a harmful chemical reagent and must be handled and disposed of appropriately.

2. Safety

Potassium dichromate is one of the most common causes of chromium dermatitis;chromium is highly likely to induce sensitization leading to dermatitis, especially of the hand and fore-arms, which is chronic and difficult to treat. Toxicological studies have further illustrated its highly toxic nature. With rabbits and rodents, concentrations as low as 14 mg/kg have shown a 50% fatality rate amongst test groups.  Aquatic organisms are especially vulnerable if exposed, and hence responsible disposal according local environmental regulations is advised.

As with other CrVI compounds, potassium dichromate is carcinogenic and should be handled with gloves and appropriate health and safety protection. The compound is also corrosive and exposure may produce severe eye damage or blindness. Human exposure further encompasses impaired fertility, heritable genetic damage and harm to unborn children.

3. Production


Potassium dichromate is usually prepared by the reaction of potassium chloride on sodium dichromate. Alternatively, it can be obtained from potassium chromate by roasting chrome ore with potassium hydroxide. It is soluble in water and in the dissolution process it ionizes:

K2Cr2O7 → 2 K+ + Cr2O72-

Cr2O72- + H2O ⇌ 2 CrO42- + 2 H+

4. Natural occurrence

A ~10 mm crystal of potassium dichromate in the same form as the mineral lopezite

Potassium dichromate occurs naturally as the rare mineral lopezite. It has only been reported as vug fillings in the nitrate deposits of the Atacama desert of Chile and in the Bushveld igneous complex of South Africa.

5. Accidental Release Measures

Ventilate area of leak or spill. Wear appropriate personal protective equipment . Spills: Sweep up and containerize for reclamation or disposal. Vacuuming or wet sweeping may be used to avoid dust dispersal. US Regulations (CERCLA) require reporting spills and releases to soil, water and air in excess of reportable quantities.

6. Handling and Storage

Protect against physical damage. Store in a dry location separate from combustible, organic or other readily oxidizable materials. Avoid storage on wood floors. Remove and dispose of any spilled dichromates; do not return to original containers. Wear special protective equipment (Sec. 8) for maintenance break-in or where exposures may exceed established exposure levels. Wash hands, face, forearms and neck when exiting restricted areas. Shower, dispose of outer clothing, change to clean garments at the end of the day. Avoid cross-contamination of street clothes. Wash hands before eating and do not eat, drink, or smoke in workplace. Containers of this material may be hazardous when empty since they retain product residues (dust, solids); observe all warnings and precautions listed for the product.

1-Bromo-3,5-difluorobenzene Properties

1-Bromo-3,5-difluorobenzene , its cas register number is 461-96-1. It also can be called Benzene, 1-bromo-3,5-difluoro ; 3,5-Difluorobromobenzene . 1-Bromo-3,5-difluorobenzene (CAS NO.461-96-1) is a clear colourless to light yellow liquid.

1. Properties

Name:1-Bromo-3,5-difluorobenzene

EINECS:416-710-2

Molecular Formula:C6H3BrF2

CAS Registry Number:461-96-1

Synonyms:1-bromo-3,5-difluoro-benzene; 3,5-Difluorobromobenzene; 3,5-Difluoro-1-Bromobenzene; 1-Bromo-3,5-Difluorobromobenzene; Benzene, 1-bromo-3,5-difluoro-; 1,3-Difluoro-5-bromobenzene; 3,5-Difluoro-Bromobenzene;

InChI:InChI=1/C6H3BrF2/c7-4-1-5(8)3-6(9)2-4/h1-3H

Appearance:colorless clear liquid

Molecular Weight:192.99

Density:1.676

Boiling Point:140℃

Melting Point:-27℃

Flash Point:45℃

Storage Temperature:Flammables area

Refractive index:1.498-1.5

Solubility:0.238 g/L (20 oC)

Usage:Intermediates of Liquid Crystals

2. Safety information

Hazard Codes: Xn,Xi , N,  F,

The Risk Statements information of  1-Bromo-3,5-difluorobenzene :

10:  Flammable

22:  Harmful if swallowed

38:  Irritating to the skin

43:  May cause sensitization by skin contact

36/37/38:  Irritating to eyes, respiratory system and skin

48/22:  Harmful: danger of serious damage to health by prolonged exposure if swallowed

50/53:  Very Toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment

The Safety Statements information of  1-Bromo-3,5-difluorobenzene:

16:  Keep away from sources of ignition – No smoking

24:  Avoid contact with skin

26:  In case of contact with eyes, rinse immediately with plenty of water and seek medical advice

36:  Wear suitable protective clothing

60:  This material and/or its container must be disposed of as hazardous waste

61:  Avoid release to the environment. Refer to special instructions safety data sheet

36/37:  Wear suitable protective clothing and gloves

RIDADR: UN 1993 3/PG 3

WGK Germany:2

Hazard Note:Flammable

Cypermethrin Toxicological Effects

Cypermethrin is a synthetic pyrethroid insecticide used to control many pests, including moth pests of cotton, fruit and vegetable crops . It is also used for crack, crevice and spot treatment for control of insect pests in stores, warehouses, industrial buildings, houses, apartment buildings, greenhouses, laboratories and on ships, railcars, buses, trucks and aircraft. It may also be used in non-food areas in schools, nursing homes, hospitals, restaurants, hotels, and in food processing plants and as a barrier treatment insect repellent for horses . Cypermethrin is available in emulsifiable concentrate, ULV, and wettable powder formulations. Technical cypermethrin is a mixture of eight different isomers, each of which may have its own chemical and biological properties.

1. Acute Toxicity

Cypermethrin(CAS.NO:52315-07-8) is a moderately toxic material by dermal absorption or ingestion . It may cause irritation to the skin and eyes. Symptoms of dermal exposure include numbness, tingling, itching, burning sensation, loss of bladder control, incoordination, seizures and possible death . Pyrethroids may adversely effect the central nervous system. Human volunteers given dermal doses of 130 ug/cm2 on the earlobe experienced local tingling and burning sensations. One man died after eating a meal cooked in a 10% cypermethrin concentrate that was mistakenly used for cooking oil. Shortly after the meal, the victim experienced nausea, prolonged vomiting, stomach pains, and diarrhea which progressed to convulsions, unconsciousness and coma. Other family members exhibited milder symptoms and survived after hospital treatment. Rats fed high doses of 37.5 mg/kg of the cis-isomer of cypermethrin for 5 weeks exhibited severe motor incoordination, while 20-30% of rats fed 85 mg/kg died 4 to 17 days after treatment began . Cypermethrin is not a skin or eye irritant, but it may cause allergic skin reactions .

The amount of a chemical that is lethal to one-half (50%) of experimental animals fed the material is referred to as its acute oral lethal dose fifty, or LD50. The oral LD50 for cypermethrin in rats is 250 mg/kg (in corn oil) or 4,123 mg/kg (in water) . EPA reports an oral LD50 of 187 to 326 mg/kg in male rats and 150 to 500 mg/kg in female rats . The oral LD50 also varies from 367 to 2,000 mg/kg in female rats, and from 82 to 779 mg/kg in mice, depending on the ratio of cis/trans-isomers present. This wide variation in toxicity may reflect different mixtures of isomers in the materials tested. The oral LD50 reported in rabbits is 3,000 mg/kg . The dermal LD50 in rats is 1,600 mg/kg , and in rabbits is > 2,000 mg/kg  or > 4,800 mg/kg .

2. Chronic Toxicity

Long-term exposure to cypermethrin may cause liver changes. Pathological changes in the cortex of the thymus, liver, adrenal glands, lungs and skin were observed in rabbits repeatedly fed cypermethrin.

1).Reproductive Effects

No adverse effects on reproduction were observed in a 3-generation study with rats given doses of 37.5 mg/kg, the highest dose tested .

2). Teratogenic Effects

FAO has reported that cypermethrin is not teratogenic. No birth defects were observed in the offspring of rats given doses as high as 70 mg/kg/day nor in the offspring of rabbits given doses as high as 30 mg/kg/day.

3).Mutagenic Effects

FAO has reported that cypermethrin is not mutagenic, but tests with very high doses on mice caused a temporary increase in the number of bone marrow cells with micronuclei. Other tests for mutagenic effects in human, bacterial and hamster cell cultures and in live mice have been negative .

4).Carcinogenic Effects

EPA has classified cypermethrin as a weak possible human carcinogen because there is some evidence that it caused benign lung tumors in only one sex and one species (female mice) tested, and then only at the highest dose tested (1,600 ppm). No tumors occurred in rats given doses of up to 75 mg/kg.

5).Organ Toxicity

Pyrethroids may cause adverse effects on the central nervous system. Long-term feeding studies have caused increased liver and kidney weights and adverse changes to liver tissues in test animals.

6).Fate in Humans and Animals

In humans, urinary excretion of cypermethrin metabolites was complete 48 hours after the last of 5 daily doses of 1.5 mg. Studies in rats have shown that cypermethrin is rapidly metabolized by hydroxylation and cleavage, with over 99% being eliminated within hours. The remaining 1% becomes sequestered in body fat. This portion is eliminated slowly, with a half-life of 18 days for the cis-isomer and 3.4 days for the trans-isomer.