CAMPHOR. 



CAMPHOR. 



642 



portant to distinguish them. Artificial camphor, when heated, gives 

 off the odour of turpentine, and, when ignited, burns with a sooty 

 flame. The action of polarised light also serves to distinguish them. 

 According to Mr. Bailey, if a fragment be placed on a microscopic 

 slide, and a drop of alcohol added, it will first dissolve, and re-crystallise 

 as the spirit evaporates. Examining this with the aid of a polarised 

 light, the crystals of true camphor will seem as if beautifully coloured ; 

 but not so those of the artificial product. 



CAMPHOR (C^HjgO.,). Ordinaiy commercial, or laurel camphor, is 

 a product of the Laurus camphora, a tree growing abundantly in China 

 and Japan. The following is the method of extraction adopted in the 

 latter country. The roots and wood of the tree are cut up and 

 boiled with water in large pans fitted with heads in which are placed 

 reeds or rice straw ; on these the camphor condenses, being carried 

 up by the steam. In China, the chopped wood is steeped in water, 

 and boiled till camphor adheres to the stirrer, the liquid is then 

 strained off, and on standing the camphor separates out. Obtained by 

 either method it requires purification, and this is an operation exten- 

 sively practised in England. It consists in mixing the camphor with 

 lime, and heating on a sand-bath in thin glass vessels of the shape of 

 an onion, about a foot in diameter, called bomboloes. As the tempe- 

 rature rises the camphor fuses, boils and condenses in the upper part 

 of the vessel ; at the end of the operation these are cracked by 

 sprinkling with cold water, and the hemispherical cakes taken out and 

 trimmed. They usually weigh from ten to twelve pounds. 



Camphor obtained by sublimation, or from solution in alcohol, 

 crystallises in octohedra or segments of the same ; white, brilliant, and 

 almost as transparent as glass. Specific gravity '986 to '996, according 

 to temperature. It has a pungent bitter taste, and peculiar aromatic 

 odour. It slowly evaporates at common temperatures, condensing in 

 beautiful plates on the sides of the vessel in which it is contained. 

 Light seems to favour this evaporation ; it takes place most rapidly 

 when camphor is in contact with water, and gives rise to those peculiar 

 gyratory movements which are observed when small pieces are thrown 

 on to the surface of that liquid. Camphor is tough, and difficult to 

 powder, unless slightly moistened with alcohol, when the operation 

 becomes an easy one. Heated, camphor fuses at 347, boils at 399, 

 and distils without decomposition. Its vapour density is 5'317. It 

 dissolves in one thousand times its weight of water, forming the 

 camphor-water, mixture, or julep, of pharmacy. It is very soluble in 

 alcohol, ether, acetic acid, fixed and volatile oils, chloroform, and 

 bisulphide of carbon. Alkaline solutions seem to have but little 

 action on it. It absorbs variable quantities of hydrochloric acid, 

 sulphurous acid, and hyponitrous acid gases, oily bodies being formed, 

 from which water separates the camphor unchanged. Heated with 

 anhydrous phosphoric acid, fused chloride of zinc, or concentrated 

 sulphuric acid, it yields ft/mine (C^H^) (camphoyen) and water. Left 

 in contact with excess of sulphuric acid for some days, it yields, on 

 diluting the mixture with water, an oily body, colourless when pure, 

 and having the same composition and state of condensation as solid 

 camphor : it is changed into the latter by caustic potash. Chlorine 

 acts slowly upon camphor, giving rise to unstable products, in 

 which that element replaces hydrogen in variable quantities. Bromine 

 forms with it a crystallisable substance (C^H^O^Er.,). Iodine acts 

 more energetically, giving rise to several compounds. Perchloride of 

 phosphorus decomposes it, forming a body closely resembling arti- 

 ficial camphor ; perchloride of antimony also strongly attacks it. 



Cnmpkmne, is the name given by M. Fre'my to a liquid, obtained by 

 passing the vapour of camphor over red-hot lime. Boiling point 167. 



Campholii- add (C 20 H 18 4 ), is formed by subjecting camphor and 

 hydrate of potash to heat under pressure. 



c,,n,.o, + Ko, HO = c, n 17 KO,. 



Camphor. Potash. Campliolatc of 

 potash. 



It may be isolated by precipitating with an acid an aqueous solution 

 of the resulting salt. It is insoluble in water. Heated, it fuses at 

 176, and at about 482 boils and evaporates without decomposition. 

 Its vapour density is 6'058. It is a monobasic acid. The lime salt 

 (C M) H,,Ca0 4 ) is formed by adding chloride of calcium to a hot solution 

 of campholic acid in excess of ammonia : it is a crystalline powder. 



tamphnlrme (CjjH.,,0.,) Is a product of the dry distillation of cam- 

 pholate of lime. 



J(C, n,,CaO.) = 2(CaO CO,) + (C 3 ,H 34 O.,). 



Campholate of lime. Carbonate of Campholoiic. 

 lime. 



i;i,,,j,!,,,l, ,. ii |i , , U a liquid hydrocarbon, obtained by diHtilling 

 i impholic acid with anhydrous phosphoric acid. 



Camphoric arid (C^H^O^SHO) results from the action of boiling 

 concentrated nitric acid upon camphor till no more red fumes are 

 evolved. It crystallises out on cooling, and may be freed from any 

 undecomposed camphor by dissolving in solution of carbonate o: 

 potash, precipitating with nitric acid, and re-crystallising from water 

 The crystals are either Ian imilar; they have a sour anc 



somewhat bitter taste, Melting point 158. This acid is but slightly 

 soluble in cold water, more so whni Imilwl; alcohol, ether, and the 

 fixed and essential oils dissolve it with facility. 



Camphoric acid unites with salifiable bases to form salts called 



mpbaratet. Not one of them is applied to any purpose whatever. 

 Those which are soluble have almost all of them an aromatic bitter 

 aste ; the aqueous solutions are decomposed by the stronger acids, and 

 they all burn and are decomposed by heat. 



Anhydrous camphoric acid (C 20 H 14 6 ) is produced by distilling the 

 lydrated acid, water being separated at the same time. The sublimate 

 may be obtained in prisms of considerable length, by re-crystallisation 

 :rom boiling alcohol. They are nearly tasteless, but after a time 

 produce considerable irritation in the throat. Water dissolves them in 

 small quantity. In ether they dissolve readily. Heated to 266 they 

 3egin to sublime in beautiful needles, at about 423 fuse into a colour- 

 'ess liquid, and boiling at 518, distil over without undergoing decom- 

 position. Anhydrous camphoric acid may be digested with hot water 

 for two or three hours, without combination taking place ; continued 

 ebullition however ultimately determines the formation of the hydrate. 

 The former does not precipitate neutral acetate of lead, the latter does 

 so abundantly. 



Camphoric acid is bibasic, and forms well defined salts with nearly 

 all the bases. General formula (C. Hi,M,O,). They are for the 

 most part crystallisable, soluble in water, and decomposed by the 

 stronger acids. 



Sulphocamphoric acid (C J8 H 10 Sj0 12 + 4Aq). When anhydrous cam- 

 phoric acid is heated with fuming sulphuric acid, carbonic oxide 

 escapes, and from the solution diluted with water, filtered through 

 asbestos and exposed in vacuo, the sulpho-acid crystallises out. It 

 may be purified by solution in, and recrystallisation from, alcohol. 



+ 2(HO, SO,) = (C 18 H 16 S S 1S ) + 2HO. 



Anhyd.-camph. acid. 



Sulpho-camph. acid. 



The crystals are colourless, bitter, soluble in water, alcohol, and 

 ether. Exposed in a vacuum they lose four atoms of water. Between 

 320 and 330 they fuse and soon begin to decompose. They are dis- 

 solved by boiling nitric acid without decomposition. Sulpho-camphoric 

 acid is bibasic, the neutral salts having the formula C, 9 H 14 M 2 S a ls . 



Campho-methylic acid or methyl-camphoric acid (C 20 H 15 (C,,H.,)O B ), and 

 Campho-ethylic or ethyl-camphoric or camphovinic acid (C M) H ls (C 4 H 5 )O a ) , 

 may be represented as camphoric acid in which an equivalent of 

 hydrogen is replaced by the radicals methyl and ethyl respectively. 

 They are obtained by digesting together for some time a boiling 

 mixture of camphoric and sulphuric acids with the respective alcohols, 

 namely, wood spirit and spirit of wine : on diluting with water they 

 separate out. Both are colourless. Methyl-camphoric acid occurs in 

 acicular crystals. Ethyl-camphoric acid is a thick oily body. They 

 form salts with most of the bases. 



Camphoric ether or camphorate of ethyl (C 20 H 14 (C 4 H. i ), ! 8 ) results 

 from the dry distillation of ethyl-camphoric acid according to the 

 following equation : 



2(C lll) H 15 (C 4 H. i )0 9 ) = 2HO + 

 Ethyl-camphor, acid. 



^O^' + C 20 H 14 (C 4 H,,).,0 8 



Anhyd.-camphor Camphorate of ethyl. 

 acid. 



Chlorine attacks this body, giving rise to camphorate of biehlorethyl 



(CUH^CACUA)- 



Camphoramic acid (C ?0 H 17 N0 ) is obtained, combined with ammonia, 

 on passing dry ammoniaeal gas through an alcoholic solution of an- 

 hydrous camphoric acid ; on adding dilute hydrochloric acid and 

 evaporating, it crystallises out. When the crystallisation of this acid 

 from a hot aqueous solution is seen through a microscope it presents a 

 very beautiful appearance. 



Camphoramide (C 20 H, 8 N 2 4 ) is prepared by passing a current of 

 ammoniacal gas into a solution of anhydrous camphoric acid in absolute 

 alcohol. On evaporation the camphoramide is left as a syrupy matter 

 insoluble in water. 



Camphorimide (C. !0 H 15 N0 4 ). When camphoramic acid is heated to a 

 few degrees above 3~UO, water is evolved, and campliorimide remains. 

 It may be crystallised from solution in boiling alcohol. 



Camphdranilic acid or phenyl-camphoramic acid (C 20 H la (C 1 ,,H 5 )N0 ), 

 as will be seen from the formula, differs from camphoramic acid in 

 containing an equivalent of the radical phenyl (C^H^) in the place of 

 an equivalent of hydrogen. 



Camphuranile or phenyl-camphorimide (C. !0 H 14 (C 1 ,,H. i )N0 4 ) bears a 

 similar relation to camphorimide. Both the foregoing auilides are 

 produced when a mixture of anhydrous camphoric acid and aniline is 

 heated ; they may be separated by digesting in solution of ammonia, 

 when the phenyl-camphoramic acid dissolves and the phenyl cam- 

 phorimide remains insoluble. 



A variety of camphor (C^H^O.,) called by Gerhardt lorwol, and 

 more generally known as Borneo or Sumatra camphor, is found in the 

 crevices of the wood of the Dri/obalanops aromatica, a noble b*e 

 growing in those islands. The old trees are cut down, split to pieces, 

 and the little grains of camphor picked out by hand. The yield of one 

 tree is generally very small, and but little of this variety is sent to 

 Europe. It differs somewhat in its chemical and physical characters 

 from ordinary or laurel camphor. As shown by the formula it con- 

 tains two additional equivalents of hydrogen ; its melting point and 



