SUMMARY / RELATED TOPICS

Ammonium nitrate

Ammonium nitrate is a chemical compound, the nitrate salt of the ammonium cation. It has the chemical formula NH4NO3, simplified to N2H4O3, it is a white crystalline solid and is soluble in water. It is predominantly used in agriculture as a high-nitrogen fertilizer, its other major use is as a component of explosive mixtures used in mining and civil construction. It is the major constituent of ANFO, a popular industrial explosive which accounts for 80% of explosives used in North America. Many countries are phasing out its use in consumer applications due to concerns over its potential for misuse. Ammonium nitrate is found as a natural mineral in the driest regions of the Atacama Desert in Chile as a crust on the ground and/or in conjunction with other nitrate and halide minerals. Ammonium nitrate was mined there in the past, but 100% of the chemical now used is synthetic; the industrial production of ammonium nitrate entails the acid-base reaction of ammonia with nitric acid: HNO3 + NH3 → NH4NO3Ammonia is used in its anhydrous form and the nitric acid is concentrated.

This reaction is violent owing to its exothermic nature. After the solution is formed at about 83% concentration, the excess water is evaporated to an ammonium nitrate content of 95% to 99.9% concentration, depending on grade. The AN melt is made into "prills" or small beads in a spray tower, or into granules by spraying and tumbling in a rotating drum; the prills or granules may be further dried and coated to prevent caking. These prills or granules are the typical AN products in commerce; the ammonia required for this process is obtained by the Haber process from hydrogen. Ammonia produced by the Haber process is oxidized to nitric acid by the Ostwald process. Another production method is a variant of the Odda process: Ca2 + 2 NH3 + CO2 + H2O → 2 NH4NO3 + CaCO3The products, calcium carbonate and ammonium nitrate, may be separately purified or sold combined as calcium ammonium nitrate. Ammonium nitrate can be made via metathesis reactions: 2SO4 + Ba2 → 2 NH4NO3 + BaSO4 NH4Cl + AgNO3 → NH4NO3 + AgCl Ammonium nitrate reacts with metal hydroxides, releasing ammonia and forming alkali metal nitrate: NH4NO3 + MOH → NH3 + H2O + MNO3 Ammonium nitrate leaves no residue when heated: NH4NO3 → N2O + 2H2OWhen heated or exploded the predominant reaction is: 2NH4NO3 → 2N2 + O2 + 4H2OAmmonium nitrate is formed in the atmosphere from emissions of NO, SO2, NH3, is a secondary component of some PM10 particulates.

Transformations of the crystal states due to changing conditions affect the physical properties of ammonium nitrate. These crystalline states have been identified: The type V crystal is a quasicubic form related to caesium chloride, the nitrogen atoms of the nitrate anions and the ammonium cations are at the sites in a cubic array where Cs and Cl would be in the CsCl lattice. Ammonium nitrate is an important fertilizer with the NPK rating 34-0-0, it is less concentrated than urea, giving ammonium nitrate a slight transportation disadvantage. Ammonium nitrate's advantage over urea is that it is more stable and does not lose nitrogen to the atmosphere. Ammonium nitrate is not, in the form it is sold, an explosive, but it forms explosive mixtures with varying properties when combined with primary explosives such as azides or with fuels such as aluminium powder or fuel oil. ANFO is a mixture of 94% ammonium nitrate and 6% fuel oil used as a bulk industrial explosive, it is used in coal mining, metal mining, civil construction in undemanding applications where the advantages of ANFO's low cost and ease of use matter more than the benefits offered by conventional industrial explosives, such as water resistance, oxygen balance, high detonation velocity, performance in small diameters.

Ammonium nitrate-based explosives were used in the Sterling Hall bombing in Madison, Wisconsin, 1970, the Oklahoma City bombing in 1995, the 2011 Delhi bombings, the 2011 bombing in Oslo, the 2013 Hyderabad blasts. In November 2009, a ban on ammonium sulfate, ammonium nitrate, calcium ammonium nitrate fertilizers was imposed in the former Malakand Division – comprising the Upper Dir, Lower Dir, Swat and Malakand districts of the North West Frontier Province of Pakistan – by the NWFP government, following reports that those chemicals were used by militants to make explosives. Due to these bans, "Potassium chlorate – the stuff that makes matches catch fire – has surpassed fertilizer as the explosive of choice for insurgents." Ammonium nitrate is used in some instant cold packs, as its dissolution in water is endothermic. It was used, in combination with independently explosive "fuels" such as guanidine nitrate, as a cheaper alternative to 5-aminotetrazole in the inflators of airbags manufactured by Takata Corporation, which were recalled as unsafe after killing 14 people.

The solution of ammonium nitrate with nitric acid, called Cavea-b showed promise for use in spacecraft as a more energetic alternative to the common monopropellant hydrazine. A number of trials were carried out in the sixties but the substance ended up not being adopted by NASA. Health and safety data are shown on the safety data sheets available from suppliers and found on the internet. In response to several explosions resulting in the deaths of numerous people, U. S. agencies of Environmental Protection, Occupational Health an

Humulone

Humulone, a vinylogous type of organic acid, is a bitter-tasting chemical compound found in the resin of mature hops. Humulone is a prevalent member of the class of compounds known as alpha acids, which collectively give hopped beer its characteristic bitter flavor. In terms of structure, humulone is a phloroglucinol derivative with three isoprenoid side-chains. Two side-chains are prenyl groups and one is an isovaleryl group; the acidity of the ring enol moieties that give rise to its designation as an acid lie in their vinylogous relationship with the ring and side chain carbonyl functional groups. During the brewing process, humulone degrades to cis- and trans-isohumulone; these “alpha acids” survive the boiling process, although numerous oxidized derivatives are produced. The iso-alpha acids are more soluble than humulone at the pH levels present in the brewing process. Humulone can be synthesized by the acylation of 1,2,3,5-benzenetetrol with isovaleryl chloride to give 2,3,4,6-tetrahydroxyisovalerophenone.

This step is followed by prenylation with 1-bromo-3-methyl-2-butene to give humulone. As determined by INADEQUATE 2D NMR, the biosynthesis of humulone in Humulus lupulus starts with an isovaleryl-CoA unit and 3 malonyl-CoA units catalyzed by phlorovalerophenone synthase; this conversion yields the benzenoid 3-methyl-1-butan-1-one. Dimethylallyl pyrophosphate is obtained from the deoxyxylulose pathway, where prenylation of the benzenoid occurs, yielding humulone. Isovaleryl-CoA + 3 malonyl-CoA → 4 CoASH + 3 CO2 + 3-methyl-1-butan-1-one3-methyl-1-butan-1-one + 2 DMAPP →C21H30O5 Humulone is under basic research with in vitro studies to determine if it has biological properties, such as possible GABAA receptor activity or antibacterial effects

Dzintars Zirnis

Dzintars Zirnis is a Latvian football defender. He plays for Latvian First League club FK 1625 Liepāja. For his entire career Zirnis played for FK Liepājas Metalurgs in the Latvian Higher League, making his debut in 1997 and playing there until 2013, he was a member of Latvia national football team. Zirnis played for FK Pārdaugava Rīga before joining FK Liepājas Metalurgs in 1997. In September 2004 he played in the UEFA Cup for Metalurgs in which the club beat Faroe Islands club, B36 Tórshavn 11-2 over two legs in the first qualifying round and beat the Swedish Allsvenskan club Östers IF in the second qualifying round. Metalurgs were beaten by the German Bundesliga club FC Schalke 04 in the first round, 9-1 over two legs. On 1 October 2005 Zirnis was a part of the Metalurgs team that beat FK Ventspils 5-1 to seal the club's first Latvian Higher League title. Zirnis ended his professional career after the 2013 Latvian Higher League season, having played 403 league matches and scored 7 goals, he is one of the most capped players in the history of the Latvian top tier championship behind his ex-teammate Viktors Spole and Igors Korabļovs.

Zirnis made his debut for Latvia national football team on 19 August 1997 in a 0-0 draw with Azerbaijan. In November 2003 he was a part of the Latvian team that beat Turkey over two legs to qualify for the UEFA Euro 2004 finals, for the first time qualifying for a major international tournament, and played at the finals in 2004. Zirnis was sent off in the Baltic Cup final against Lithuania in Kaunas on 22 May 2005. On 17 November 2007 he scored an own goal to give Liechtenstein the lead in a UEFA Euro 2008 qualifying Group F match which Latvia won 4-1. Zirnis played 68 international matches for Latvia. Club Virsliga Champion: 2005, 2009 Virsliga Runner-up: 2003, 2004, 2006, 2007, 2008, 2011 Latvian Cup Winner: 2006 Baltic League Champion: 2007 Dzintars Zirnis at Soccerbase Dzintars Zirnis at National-Football-Teams.com