Nitro

Peroxizii
---------
Tetraoxidul de Ruteniu si Osmiu
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
OsO4; RuO4
        In contactul direct cu alcoolul etilic explodeaza, iar in contact cu
pielea apre o reactie de oxidare ce se manifesta prin inegrirea tesuturilor.

Peroxizi alcalini
~~~~~~~~~~~~~~~~~
        Li2O2 - culoare alba ;  temperatura de topire 198øC
        Na2O2 - culoare galbena;temperatura de topire 460øC
        Cs2O2 - culoare galbena;temperatura de topire 594øC
             (ultimi doi se descompun cu degajare de O)

                              tøC
                        X2O2 ----->X2O + 1/2 O2

Peroxizii de Li si Na sunt stabili in aer.
Sunt agenti oxidanti foarte puternici, atit in solutii cit si in stare uscata.
Reactiile de oxidare in contact cu Sulful, Carbunele, pulberea de Al, celuloza
etc., sunt insotite de flacara, iar in anumite conditii cu explozie.

Peroxizi tranzitionali
~~~~~~~~~~~~~~~~~~~~~~
        Cuprul (I), argintul (I) si mecurul (I) genereaza peroxizii de tipul
X2O2, foarte nestabili, care la incalzire se descompun cu explozie.
        Nichel (II) si mercur (II) dau peroxizi de tipul XO2;
(Peroxidul de Hg a-HgO2 -galben; b-HgO2 rosu). Sunt nestabili, iar prin
frecare sau incalzire se descompun cu explozie.

        Obtinerea peroxizilor
        ~~~~~~~~~~~~~~~~~~~~~
        -Li2O2 , rezulta prin actiunea apei oxigenate asupra unei solutii
saturate de Hidroxid de Li la 95øC. Lucrind la temperatura camerei, in mediu
de alcool, se separa cristale mici incolore de Li2O2ùH2O2ù3H2O
        -Na2O2 , industrial se obtine prin oxidarea sodiului in aer uscat, in
vase de Al.

Boranii
-------
        Sub actiunea acizilor asupra borurii de Mg se obtine un amestec de
borani din care au fost izolati in stare pura:

                B2H6;      B4H10;B5H9;B5H11;B6H10;      B10H14
                 gaz              lichizi                solid

Boranii sunt substante incolore, cu miros neplacut, foarte toxici, se aprind
spontan si in oxigen si clor explodeaza!

Oxigen - O2
~~~~~~~~~~~
1)
        Din 50 g permanganat de potasiu se obtine aproximativ 4,5l oxigen:

                       tøC
                2KMnO4 ---> K2MnO4  +  MnO2  +  O2

2)
        Dintr-un amestec format din 6 g clorat de potasiu si 4 g dioxid de
mangan se obtine aproximativ 2,7 l oxigen:

                                 tøC
                2KClO3  +  MnO2  ---> 2KCl  +  3O2

        O mica cantitate din amestec se incearca in prealabil intr-o eprubeta.
Daca descompunerea nu se desfasoara lin, daca se produc pocnituri nu se
foloseste amestecul.
        Dioxidul de Mn a fost impurificat cu carbon, sau o alta substanta
combustibila si amestecul lui cu clorat de potasiu poate produce o explozie
grava.

Cloriti - XClO2
---------------
        Se obtin in amestec cu cloratii, introducind un curent de ClO2
printr-o solutie a unui hidroxid alcalin. Cloritul respectiv poate fi separat
de cloratul cu care este amestecat, prin cristalizare fractionata.
        Daca se introduce un curent de ClO2 in prezenta apei oxigenate
(vezi "Substante utile") se obtine clorit fara clorat, apa oxigenata jucind
rolul de substanta reducatoare.

                2ClO2 _ H2O2 + 2NaOH ----> 2NaClO2 + 2H2O + O2

Cloritii fac explozie prin lovire sau incalzire. Erau folositi la inalbirea
tesuturilor (cloritul de Na).

Peroxid de bariu
~~~~~~~~~~~~~~~~
        Este folosit ca component al bombelor incendiare.
        Se obtine prin incalzirea oxidului de bariu la 500-600øC, in atmosfera
de oxigen:

                BaO  +  1/2O2 <---> BaO2        (anhidru)

        Se mai poate prepara sub forma de octahidrat prin tratarea
hidroxidului de Ba cu apa oxigenata 30%:

        Ba(OH)2  +  H2O2  +  6H2O ---> BaO2ù8H2O

Azotura de cobalt
~~~~~~~~~~~~~~~~~
CoN - este o subtanta pirofora.

Fosfor alb
~~~~~~~~~~
P
        Se obtine incalzind la 1500-1600øC fosfat tricalcic, nisip si carbune:

I)           2Ca3(PO4)2  +  6SiO2 ---> P4O10  +  6CaSiO3

II)          P4O10  +  10C ---> P4 + 10CO

        Fosforul alb este obtinut sub forma de vapori. Ei se condenseaza in
vase cu apa racita. Se topeste la 44,1øC si fierbe la 280,5øC; se aprinde la
60øC. Se pastreaza in vase cu apa spre a se feri de oxigen. Se dizolva in
benzen, toluen etc. Este foarte toxic. Poate fi folosit la umplerea bombelor
incendiare.

Azotat de bariu, Clorat de bariu
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Ba(NO3)2 , Ba(ClO3)2
        Sunt folositi pentru a colora in verde focurile de arificii:

Azotat de strontiu
~~~~~~~~~~~~~~~~~~
Se foloseste in amestec cu carbunele si sulful pentru a colora in rosu
focurile si semnalele luminoase. Se obtine din carbonat de strontiu si acid
azotic.

Obtinere
~~~~~~~~
Se foloseste : - 1 parte glicerina
               - 2,05 parti Acid azotic
               - 3,19 parti Acid sulfuric
*Raporturile se refera la masa reactantilor

        Se amesteca acidul azotic cu acidul sulfuric cu mare atentie deoarece
se degaja caldura, concomitent se raceste amestecul respectiv intr-o baie de
gheata.
        Se adauga glicerina in proportii mici, agitinduse usor continutul. In
tot acest timp se continua racirea cu gheata.
        Dupa dizolvarea glicerinei se asteapta citeva minute ÷ 15 dupa care se
toarna un volum dublu de apa racita cu gheata, peste amestecul din reactia
anterioara (Apa se va adauga prin prelingere).
        La sfirsit se va agita usor amestecul, astfel, pe fundul vasului va
ramine nitroglicerina, sub forma unei substante uleioase.

Nota:
~~~~~
       - Pe tot timpul desfasurarii reactiei, temperatura amestecului
trebuie sa aiba in jur de 10øC, dar in nici un caz sa nu depaseasca 30øC.
       - Surplusul de apa se va elimina, raminind nitroglicerina pura.
       - Acidul sulfuric se adauga peste cel azotic, prin agitare continua
         si racire permanenta.

Reactia:
        CH2 - O - NO2     HONO2        CH2 - O - NO2
        |                              |
        CH  - O - NO2  +  HONO2  ----> CH  - O - NO2  +  3H2O
        |                              |
        CH2 - O - NO2     HONO2        CH2 - O - NO2

         (glicerina)      (Acid         (Trinitrat de
                          Azotic)         glicerina)

        Trinitratul de glicerina este un ester, si nu un nitroderivat, grupa
 -NO2 nefiind legata direct de atomul de C, ci prin intermediul unui atom de O.
Explodeaza usor prin zdruncinare sau lovire, fiind una din substantele
explozive cele mai puternice. Nestabilitatea se explica prin faptul ca in
molecula sa se gaseste o cantitate suficienta de atomi de oxigen cu care sa se
transforme cu atomi de Carbon in CO2 si cei de H in apa. Atomii de azot
prezinta o bariera intre cei de O si C insa la o usoara zdruncinare se
regrupeaza atomii, forminduse:
        CO2, H2O, N si o mare cantitate de caldura.
Conditia minima de explozie este satisfacuta de reactia in lant generata de o
singura regrupare.

ENG: Nitroglycerin.
Nitroglycerin (NG), also known as nitroglycerine, trinitroglycerin, and glyceryl trinitrate, is a chemical compound. It is a heavy, colorless, oily, explosive liquid obtained by nitrating glycerol. It is used in the manufacture of explosives, specifically dynamite, and as such is employed in the construction and demolition industries, and as a plasticizer in some solid propellants. It is also used medically as a vasodilator to treat heart conditions.
Preparation:
Nitroglycerin is prepared by nitration of glycerol (also known as glycerin). In the process, glycerin is slowly tipped into a mix of full concentration nitric acid and sulfuric acid (about 50% sulfuric acid, 40% nitric acid, and 5-10% glycerin). The mixed acid must be cooled to approximately room temperature before the glycerin is added because they will exotherm (heat up) greatly when combined. The solution is slowly stirred. A few seconds after mixing, the vessel must be immersed in a jacket of ice water to prevent the exothermic reaction from overheating it, causing nitric acid decomposition or even an explosion. The temperature should never exceed 10 °C (50 °F), but the chemicals must not be cooled by the ice water before mixing, or the nitrating reaction will not take place. If the reaction is successful, the nitroglycerin will form a slightly yellow or straw colored liquid which will float to the top of the acid mix. The mix is then carefully poured into a large container of water. The nitroglycerin will settle to the bottom (it is water insoluble) and should be neutralized with sodium carbonate and water mix until its pH becomes neutral. Another method of producing nitroglycerin is to mix the glycerin and sulfuric acid first, which produces heat, but at this stage is not dangerous. After cooling, the Nitric acid can be added reasonably quickly to the mix, but it can still cause uncontrolled nitration. It can also cause the acid to spurt back at you. Therefore it should be avoided and the nitration mixture should be added very slowly to the glycerol. The then nitrated glycerin and acid solution has to be left for the nitroglycerin to float to the top, as this method can sometimes produce the nitroglycerin in fine quantities. The waiting period is a day or less, but the prolonged exposure to the acids may cause the decomposition or even the explosion of the nitroglycerin, although the latter will only occur in large batches. If a milky colour is seen, it is only because of water in the mix, and not to be worried about. From this point, continue as above. This method was used in the time of Nobel, although it was not his own.

    Mercurul este elementul chimic aflat pe cea de-a 80-a poziţie în tabloul lui Mendeleev, cu simbolul Hg (din latinescul hydroargentum, argint lichid). Acesta este singurul metal din tabelul periodic al elementelor care este lichid la temperatura camerei ( luand tem,peratura camerei drept 20 de grade Celsius. Cesiul se topeste in jurul a 25 de grade iar galiul la 38 de grade), punctul de fuziune fiind -38 grade Celsius.Mercurul este un elemenmt cu densitate foarte mare( aproximativ 13,5 grame/ centimetru cub). Mercurul metalic se intrebuinteaza la fabricarea termometrelor, barometrelor, aerometrelor . Sarurile mercurului se folosesc in laboratoare si in medicina. De exemplu HgCl2 ( clorura mercuroasa) se foloseste ca desinfectant extern atunci cand alcoolul nu se poate folosi iar apa oxigenata sau rivanolul nu asigura o asepsie destul de temenica( de exemplu la recoltarea sangelui pentru determinarea alcoolemiei). Tot clorura mercuroasa se foloseste in laboratoarele de anatomie patologica ca si fixator la prepararea unor lame cu materie de analizat la microscop. Fulminatul de mercur se intrebuinteaza la fabricarea explozibililor(in special a capselor detonante) dar are dezavantajul; de a improsca cu picaturi de mercur metalic la momentul exploziei. Oxidul de mercur ( rosu, HgO) se intrebuinteaza la prepararea unor vopsele pentru protejarea metalelor. Clorura mercuroasa se mai intrebuinteaza la fabricarea fetrului pentru palarii. Calomelul se intrebuinteaza la electrozi pentru electroliza si electrodializa.

Utilizare:
Pe linga utilizarile in instalatiile electrochimice de laborator  (polarografia ) si in termometre, se foloseste pe scara larga in industria  chimica la fabricarea NaOH in electrizoare cu catod de mercur, iar in idustria  extractiva la separarea aurului si argintului prin amalgamare.
Amalgamele de Na se folosesc ca agenti reducatori in chimie, iar cele  de zinc si alte metale pentru plombe in stomatologie.
De asemenea joaca rolul de agent termic in reactoarele nucleare.  Sarurile sale se utilizeaza in farmacie, iar “fulminatul de mercur” la  detonarea explozivilor. Mai este folosit in pompele de difuzie cu mercur, care  permit obtinerea unui vid inaintat de ordinul a 10e-10 torr, in lampile de  iluminat etc.

ENG: Mercury
__________

Mercury is the only common metal liquid at ordinary temperatures. Mercury is sometimes called quicksilver. It rarely occurs free in nature and is found mainly in cinnabar ore (HgS) in Spain and Italy. It is a heavy, silvery-white liquid metal. It is a rather poor conductor of heat as compared with other metals but is a fair conductor of electricity. It alloys easily with many metals, such as gold, silver, and tin. These alloys are called amalgams. Its ease in amalgamating with gold is made use of in the recovery of gold from its ores.

The most important salts are mercuric chloride HgC1₂ (corrosive sublimate – a violent poison), mercurous chloride Hg₂Cl₂ (calomel, occasionally still used in medicine), mercury fulminate (Hg(ONC)₂, a detonator used in explosives), and mercuric sulphide (HgS, vermillion, a high-grade paint pigment).

Organic mercury compounds are important – and dangerous. Methyl mercury is a lethal pollutant found in rivers and lakes. The main source of pollution is industrial wastes settling to the river and lake bottoms.

As mercury is a very volatile element, dangerous levels are readily attained in air. Mercury vapour should not exceed 0.1 mg m^-3 in air. Air saturated with the vapour at 20°C contains mercury in a concentration far greater than that limit. The danger increases at higher temperatures. It is therefore important that mercury be handled with care. Containers of mercury should be securely covered and spillage should be avoided. Mercury should only be handled under in a well-ventilated area. If you are in possession of any mercury you are advised to contact a properly qualified chemist or public health laboratory for its safe disposal.

Small amounts of mercury spillage can be cleaned up by addition of sulphur powder. The resulting mixture should be disposed of carefully.

The physical appearance of mercury is well known because of its use in many thermometers. It was common to demonstrate the formation of mercury in the laboratory by heating mercury sulphide (cinnabar, HgS) but this is strongly discouraged today because of the toxicity of mercury vapours. Don’t do it! However, this method forms the basis of commercial extraction. The prepared cinnabar ore is heated in a current of air and the mercury vapour condensed.

HgS + O₂ (600°C) → Hg (l) + SO₂ (g)

The crude mercury is then washed with nitric acid and treated with air in order to remove impurities as oxides or into solution. Further purification is achieved by distillation at reduced pressure.

COCl2 – clorura de carbonil
Din punct de vedere fiziologic, clorul, chiar in cantitati mici, are o actiune vatamatoare asupra membranei pulmonare, marindu-i permeabilitatea fata de apa (plasma sangvina invadeaza, alveolele pulmonare, producind edem pulmonar).
Se obtine prin reactia cloroformului cu oxigenul din aer si sub influenta luminii.
lumina
CHCl3 + 1/2O2 ——–> COCl2 + HCl

sau:

CO + Cl₂ → COCl₂

sau:

H₂SO₄ + SO₃ + CCl₄ → 2HSO₃Cl + COCl₂