Uses of Oxalic Acid - Introduction and Applications
Oxalic acid, which is otherwise known as ethanedioic acid, is a colorless, crystalline, organic compound from the dicarboxylic acid family found in many plants. It is widely used in laundry to effectively remove ink stains and in industries for the removal of rust. For the same reason, it is the main component of many commercial preparations used to remove scale from car radiators.
The chemical formula of Oxalic acid is given by C2H2O4. Under standard temperature and pressure (STP) conditions, oxalic acid is present as a white crystalline solid. When dissolved in water, this compound is known to form a colorless solution. Oxalic acid is considered to be the simplest dicarboxylic acid because it is composed of two carboxyl groups.
Uses of Oxalic Acid
1. Removing marks, stains and rust
As mentioned above, oxalic acid is mainly used for the most demanding cleaning operations. Oxalic acid effectively removes all kinds of marks and stains from the surface of the object. It is a gentle stain remover that eats up stains but leaves the base as it is. Acids have similar properties to bleach and can be used, for example, to remove rust on metals such as plumbing pipes, kitchen countertops etc. Some cleaning agents, laundry detergents, and bleaches contain some of this acid. Oxalic acid is also ideal for polishing virtually all stones and disposing of waste wood.
2. Industrial use
In industry, this chemical is primarily used in mineral processing mechanisms. In addition, oxalic acid can be used to sterilize equipment, and people in the textile industry use it to bleach clothes. It is also used in factories for removing rust from metallic equipment.
3. Medical use of oxalic acid
In the medical field, companies use acids to further purify or dilute certain chemicals. However, there is little data on the health benefits of this acid. Oxalic acid in both organic and raw forms is not fatal. But sometimes it can have harmful effects on the body.
4. Reducing and treating element
Oxalic acid is mainly used as a reducing element in the development of photographic film. This acid is also used in wastewater treatment plants to effectively remove lime from water.
What Acid is Used to Remove Rust?
To remove the rust for the products like iron, some strong acids will be helpful.
Strong alkalis and strong acids can remove rust quickly. However, these caustic chemicals pose various safety and health risks and require that the user observe strict safety precautions. Strong acids will dissolve rust, but these strong acids will also dissolve paint, finishes, and sometimes even the metal itself. Hydrochloric acid (which is otherwise known as muriatic acid when it is in diluted form), also phosphoric acid, sulfuric acid can be used as a rust removal formula using these strong acids. These strong acids are mineral acids, and especially in concentrated forms, they are highly corrosive. Strong alkalis work in the same way, but on the opposite end of the pH spectrum.
Strong acids work by dissolving rust. Most of the acid-based rust removal products are of gel formulations. If that gel remains on the metal too long after the gel is applied, it starts dissolving it, causing pitting. While on the other side, mineral acids clean away the outer layer of rust, and also they put the underlying metal in a reactive state, making it susceptible to "flash rusting," except it is otherwise neutralized or sealed.
Oxalic Acid Application
There are many oxalic acid applications that we can take from various sources. Up to 25% of oxalic acid produced will be used as a mordant in dyeing processes. It is used as bleach, especially for pulpwood. Also, it is used in baking powder and as the third reagent in silica analysis instruments.
The oxalic acid application or the uses of oxalic acid in daily life are given below.
Cleaning
Oxalic acid application mainly includes bleaching or cleaning, especially oxalic acid as a rust remover (an iron complexing agent). Its utility in rust removal agents is because it forms a stable, water-soluble salt with ferrioxalate ion and ferric iron.
Extractive Metallurgy
Oxalic acid is a primary reagent in lanthanide chemistry. Hydrated lanthanide oxalates readily form in very strongly acidic solutions in easily filtered form, a densely crystalline, and as largely free of contamination by non-lanthanide elements. This oxalate thermal decomposition gives the oxides, the most commonly marketed form of these elements.
Niche Uses:
Oxalic acid is also used by a few beekeepers as a miticide against the parasitic varroa mite
This acid is used to clean minerals.
Oxalic acid is also sometimes used in the aluminum anodizing process, with or without sulfuric acid. Compared to the sulfuric acid anodizing, the coatings obtained are thinner and exhibit a lower surface roughness.
Physical Properties of Oxalic Acid
The molecular weight of anhydrous oxalic acid is 90.034 grams per mole. The molecular weight of the dihydrate of this organic compound is equivalent to 126.065 grams per mole.
Under standard conditions, oxalic acid exists as an essentially crystalline white solid and is odorless.
The density of anhydrous oxalic acid is 1.90 grams / cubic centimeter. The density of oxalic acid dihydrate is 1.653 grams per cubic centimeter.
Oxalic acid is very soluble in water. The solubility of this organic compound in water ranges from 90 to 100 grams per liter at a temperature of 20 degrees Celsius.
It is soluble in both ethanol and diethyl ether.
Precautions to be Taken
The pure form of oxalic acid is extremely toxic and corrosive and should be handled with care. Always wear latex gloves to protect your skin when mixing powdered acids with water. You should also use protective goggles and gas masks to prevent eye irritation and prevent harmful smoke from entering your lungs. Always mix oxalic acid in a well-ventilated area such as open ground, preferably far from residential localities. If swallowed by mistake, do not induce vomiting instead immediately contact your doctor, nearest hospital or local poison control center.
FAQs on Uses of Oxalic Acid
1. Are Strong Acids Safe for Removing Rust?
Even when the mineral acids are diluted in water or any other substances, they are dangerous to work with, and they can damage the skin severely, irritate the lungs, and can cause other health problems without the proper safety precautions. These chemicals are toxic and corrosive, so they must be disposed of safely, especially considering large amounts.
Industrial rust removal products having strong acids can be ideal for serious rust problems, which must be quickly resolved. However, these kinds of products must be carefully monitored, and the safety precautions are to followed carefully. Precautions like proper ventilation, gloves, safety goggles, and careful application are essential to keep the users protected.
2. Mention Some Oxalic Acid Uses in Food?
There are a number of oxalic acids uses in food. Lists of foods that are high in oxalic acid vary greatly from source to source. According to the University of British Columbia, the body is well known to absorb oxalic acid only from a handful of foods, including pecans, wheat bran, peanuts, spinach, rhubarb, beet greens, beets, and chocolates. While other foods are considered as high oxalic acid ones, none of the studies shown that the body readily absorbs their oxalate content. Such include sweet potatoes, soy foods, black tea, berries, and other dark leafy greens, like Collards and Swiss chard.
According to the article published in 2007 in the journal "Urologic Nursing," registered dietitian Laura R. Flagg has concluded as the data on oxalate foods causing kidney stones actually is "insufficient" and discouraged the limiting of these kinds of foods for patients with stones.