Monograph of Urea

Urea refers to an organic compound belonging to the carbamide class of chemicals, with a molecular formula of (NH2)2CO. Its name also serves as its official IUPAC nomenclature, though it is also known as carbamide, carbonyl diamide, carbonyldiamine, diaminomethanal, and diaminomethanone. Urea is under the functional group RR’N-CO-NRR’, which refers to a group of compounds with molecules having a carbonyl group attached to two organic amine residues. Popular compounds that belong to this class include allantoin, hydantoin, and carbamide peroxide. Urea’s CAS number is 57-13-6.

Urea was first synthesized by Friedrich Wöhler from an inorganic precedent. His discovery was an important milestone in the development of organic chemistry because it was the first time that a molecule from a living entity can be synthesized without any biological precursor.

Available as white crystals, powder, or prills, it is odorless when in solid state, but gives of a faint ammonia odor when dissolved in water or vapor. Urea is soluble in water, and is neither acidic nor basic when dissolved.

Physical Properties

Molecular weight: 60.06 g/mol

Density: 1.32 g/cm3

Boiling point: 197°C

Vapor pressure: 0.4 (25°C)

Vapor density: 2.07 (air=1)

Viscosity: 1.78 MP at 46% solution (20°C)

Heat of fusion: 13.9 kJ/mol

Heat of vaporization: 45.3 kJ/mol

Heat of combustion: -634.1 kJ/mol

Flash point: 73°C

Uses
Urea has been used in different applications, particularly in agricultural, chemical, and pharmaceutical industries. Majority of its global production rests in the agricultural sector, to be used as fertilizers. Among common nitrogenous fertilizers, urea has the highest nitrogen content, making it the lowest
transportation costs per unit of nitrogen nutrient. It is often applied either as top- or side-dressing in grain and cotton crops before cultivation. Foliar sprays also contain small concentrations for horticultural crops. Together with other salts, urea is also used for cloud seeding activities.

What is NOx?

NOx is the abbreviated form of nitrogen oxide, which refers to a group of highly reactive greenhouse gases that are compounds of nitrogen and oxygen in varying amounts. Nitric oxide (NO) and nitrogen dioxide (NO2) are two of its most important variants. These relatively inert gases are mostly colorless
and odorless, and are formed during combustion at high temperatures and at certain conditions. Main sources of NOx include motor vehicles, electric utilities, industrial plants, and residential units where fuel is burned. Agricultural soil, animal manure, sewage plants, and adipic acid are other emission sources that are human-influenced.

NOx ever since has been a major pollutant that poses serious environmental concerns. NO2 often envelops cities, together with the other air particles, in a reddish-brown fog. This can cause problems with landscape visibility. Because of the wind patterns on American geography, NOx can also be
transported to other regions where it is not emitted. The US Environmental Protection Agency (EPA) has expressed concerns about its increased emissions this past three decades for approximately 10 percent. However, all major pollutants like carbon monoxide, sulfur dioxide, lead, particulate matter, and other volatile organic compounds have decreased significantly since 1970. NOx greatly affects water quality as well. As nutrient concentrations increase, surface water breaks down and clarity is affected. Toxic chemicals are also formed in lakes and rivers that can affect aquatic life. When NOx reacts with partly-oxidized organic particles under sunlight, it forms tropospheric ozone. Increase of this ground-level ozone greatly contributes to global warming.

Aside from threatening the environment, NOx is downright damaging for health. When it forms nitrate particles and acid aerosols, it can cause respiratory problems because of lung tissue destruction. NO2 in particular is very poisonous and can be fatal in very high levels. Children and old patients are at high-risk especially.

Diesel urea or diesel exhaust fluid (DEF) is used to reduce NOx in exhaust gases from fuel combustion. After injecting the urea solution into the exhaust system, ammonia produced through urea hydrolysis reacts with NOx emissions. It will in turn convert emissions into nitrogen and water.

For more information on nitrogen oxide, visit the following:

•NOx Definition. (n.d.). Raypak: Hydronic Heating, Commercial Water Heating, Swimming Pool Heating; Spa heating, Boilers; Water Heaters. Retrieved May 24, 2011, from http://www.raypak.com/lownoxtech.htm

•Nitrogen Oxides Sources and Health Effects - WDNR. (2011, May 3). Wisconsin Department of Natural Resources. Retrieved May 24, 2011, from http://dnr.wi.gov/air/aq/pollutant/oxides.htm

•Nitrous Oxide | Climate Change . (2010, June 23). US Environmental Protection Agency. Retrieved May 24, 2011, from http://www.epa.gov/nitrousoxide/

Diesel Urea Storage

To get the most out of product shelf life, the ideal storage temperature is between 20°F and 85°F. Expectations for shelf life are defined in ISO 22241-3 when stored properly. Diesel Urea  will degrade in time depending on temperature and exposure to sunlight. If the maximum temperature does not exceed approximately 75° F for an extended period of time the shelf life will be easily two years. Temporary exposure to high temperatures has little or no impact on DEF. 

Diesel Urea is stored at extremely cold temperatures (the fluid will freeze at 11°F), however the product is not impacted by freezing and subsequent defrosting of the fluid. *Easy tip: keep the fluid out of the direct sunlight, extremely hot, and extremely cold temperatures for a prolonged periods of time and you will be on your way. If the fluid is stored in extremely hot temperatures the fluid is not “bad” it will simply be consumed at a higher rate by the vehicle.