How is copper chloride obtained

Reactions of obtaining CuCl₂ and CuCl

Copper(II) chloride dihydrate crystal [Wikimedia]

Be­fore we an­swer the ques­tion con­cern­ing meth­ods of the syn­the­sis of cop­per chlo­ride in this ar­ti­cle, we should note that cop­per chlo­ride can be bi­va­lent, with the for­mu­la Cu­Cl₂, and mono­va­lent, with the for­mu­la CuCl. Nat­u­ral­ly, be­cause of their dif­fer­ent quan­ti­ta­tive com­po­si­tion, they have dif­fer­ent prop­er­ties and fields of ap­pli­ca­tion. There­fore, meth­ods for the syn­the­sis of these sub­stances also dif­fers.

Ob­tain­ing bi­va­lent cop­per chlo­ride Cu­Cl₂

In nat­u­ral con­di­tions (i.e. in na­ture) this com­pound is en­coun­tered in the form of the rare min­er­al eri­ochal­cite (the chem­i­cal com­po­si­tion of the crys­talline hy­drate Cu­Cl₂·2H₂O – crys­tals of a blue col­or).

Copper(II) chloride dihydrate [Wikimedia]

As bi­va­lent cop­per chlo­ride has im­por­tant prac­ti­cal sig­nif­i­cance, the min­er­al found in na­ture is not suf­fi­cient to sat­is­fy de­mand for it, and for this rea­son nu­mer­ous meth­ods for the ar­ti­fi­cial syn­the­sis of this sub­stance have been de­vel­oped.

The main in­dus­tri­al method of syn­the­sis of bi­va­lent cop­per chlo­ride is the re­ac­tion of the chlo­ri­na­tion of cop­per sul­fide at a high tem­per­a­ture (300-400 °C). The equa­tion is:

CuS + Cl₂ = Cu­Cl₂ + S

An al­ter­na­tive method for the syn­the­sis of bi­va­lent cop­per chlo­ride is chlo­ridiz­ing roast­ing (at a tem­per­a­ture of at least 500 °C):

CuS + 2Na­Cl + 2O₂ = Cu­Cl₂ + Na₂­SO₄

The above re­ac­tions re­quire spe­cial­ized equip­ment and strict safe­ty mea­sures – for this rea­son they are only used in in­dus­try. How­ev­er, cop­per chlo­ride is fre­quent­ly used in var­i­ous types of work in the lab­o­ra­to­ry, so we should know how this sub­stance can be ob­tained in the lab­o­ra­to­ry.

In­ter­ac­tion re­ac­tion of cop­per with chlo­rine

The equa­tion is:

Cu + Cl₂ = Cu­Cl₂

The re­ac­tion of bi­va­lent cop­per ox­ide with hy­drochlo­ric acid

This method is used in the vast ma­jor­i­ty of cas­es be­cause of its ease of im­ple­men­ta­tion:

CuO + 2HCl = Cu­Cl₂ + H₂O

An al­ter­na­tive to the pre­vi­ous method which is also known as the neu­tral­iza­tion re­ac­tion:

Cu(OH)₂ + 2HCl = Cu­Cl₂ + 2H₂O

Dis­place­ment re­ac­tion, in which the acid residue of the weak­er acid is forced out by the stronger acid. In the vast ma­jor­i­ty of cas­es, wide­ly avail­able cop­per car­bon­ate Сu­CO₃ is used:

Cu­CO₃ + 2HCl = Cu­Cl₂ + H₂O + CO₂

Fi­nal­ly, the most orig­i­nal re­ac­tion, which in­volves dis­solv­ing cop­per in a mix­ture of strong acids, so-called “aqua re­gia”:

3Сu + 2H­NO₃ + 6HCl = 3Cu­Cl₂ + 2NO + 4H₂0

Bi­va­lent cop­per chlo­ride has found ap­pli­ca­tion in the de­car­boxy­la­tion and dy­ing fab­rics, and in the cop­per-coat­ing of met­als.

[Flickr, Creative commons by SamuraiGhost is licensed under CC BY 2.0]

Here you’ll find safe ex­per­i­ments with cop­per com­pounds

Meth­ods for ob­tain­ing mono­va­lent cop­per chlo­ride CuCl

Sample of copper(I) chloride [Wikimedia]

This sub­stance also has prac­ti­cal im­por­tance, and fans of chem­istry will be in­ter­est­ed to know how this com­pound can be ob­tained. Mono­va­lent cop­per chlo­ride was first ob­tained in 1666 by Robert Boyle, through the in­ter­ac­tion of mer­cury(II) chlo­ride and cop­per. In this re­ac­tion, the more ac­tive met­al, cop­per, forces mer­cury out of its salts. The equa­tion of this re­ac­tion is:

Hg­Cl₂ + 2Cu = 2Cu­Cl + Hg

The sec­ond method by which we can ob­tain mono­va­lent cop­per chlo­ride is by the ther­mal break­down of bi­va­lent cop­per chlo­ride in oxy­gen-free con­di­tions. This re­ac­tion was first car­ried out in 1799 by Joseph Louis Proust, who sep­a­rat­ed and de­scribed the chlo­rides of bi­va­lent and mono­va­lent cop­per. This equa­tion of this re­ac­tion is:

2Cu­Cl₂ = 2Cu­Cl + Cl₂

In in­dus­try, cop­per(I) chlo­ride is ob­tained by the in­ter­ac­tion of chlo­rine and an abun­dance of cop­per in a flux of cop­per(I) chlo­ride at high tem­per­a­ture.

Ampoule with chlorine [Flickr, Creative commons by Mrs Pugliano is licensed under CC BY 2.0]

It should be not­ed that chlo­rine is a high­ly tox­ic gas. Ad­di­tion­al­ly, there are also safer lab­o­ra­to­ry meth­ods, for ex­am­ple the re­duc­tion of cop­per(II) chlo­ride by sul­fur diox­ide:

2Cu­Cl₂ + SO₂ + 2H₂O → 2Cu­Cl + H₂­SO₄ + 2HCl

Or the re­duc­tion of Cu­Cl₂ by ascor­bic acid

Cop­per monochlo­ride is used for pu­ri­fy­ing acety­lene and car­bon monox­ide, and acts as a cat­a­lyst in or­gan­ic syn­the­sis and the pro­duc­tion of sev­er­al poly­mers.

Warn­ing! Don’t try to re­peat these ex­per­i­ments with­out a pro­fes­sion­al su­per­vi­sion!