Illinob Institute

of Tecimoiogy

UNIVERSITY LIBRARIES

AT 194

Polhman, E. F.

Manufacture of soaps and the recovery of glycerine

FOR

ILLINOIS INSTITUTE OF TECHNOLOGY PAUL V.GALVIN LIBRARY 35 WEST 33RD STREET CHICAGO, IL 60616

J-

THi; manufactur;] of r.oAPs

AND

THE i^i:cuvi-:uY op glycerine,

A THESIS

Presented tijf

.'■.. . . jv;'h::ann & h. v. ?/Iartin. to the PRESIDENT AND FACULTY Of

Axi"OUR INSTITUTE OF TEC13ITQL0GY For the Hegree of BAC MJ'JLQit OF SCIlcnCE IN CHTillC 'L E'TGINEHRI'IG

iln.vinp Conpletod the Prescribed Course of S^udy in CHEMICAL iO:iCi;!5-^RI!TG. 1910. I't-

Approv od ;

Profess^or of Chen^ical ''npineerlnp T)ean or t^ Bnglndorlng tTtudies^] " '

REPEHENCES .

Modem Soaps, Candles, and Glycerine,

Lambom.

Multiple Effect Evaporators.

Housetrandt.

Technology of Oils, Pats, and Waxes.

Lewkowitsch,

22124

• CI ~

THE MANUFACTURE OF SOAPS AlID THE RECOVERY OF GLYCERINE,

(MA 3<IA08 -TO amJTOATOHAM 5IKT .aMIH^OYJO '50 Yh.HVOO&W aHT

-3- PART 1.

THE MANUFACTURE OP SOAP.

The flret part of this thesis deals vdth the manufacture of soaps and the production of the waste liquor from which glycerine is recovered as a hy-product, and this recovery is dealt with in part 11, Before describing our experimental work upon this subject we will discuss soaps in general, their pro- perties, both chemical and physical, their source, formation, and the machinery necessary for their man- ufacture.

In its strict acceptlon, a soap is the com- poxond of an alkali, either potsLSsiian or sodium, with the higher fatty acids, especially with oleic (C18H34O2) , palmitic (C15H31COOH), and stearic (C17H35COOH) acids. However, the insoluble compound of a fatty acid with a heavy metal is also termed a soap, For example, there is the lead soap or lead plaster of the pharmavy, iron and chromium soaps used in dyeing and in the printing of textiles, alumina soap used as a thickner of lubri- cating oils, suid many other such. Potassium or potash soaps are usually soft, and are known as soft soaps, while sodiimi or soda soaps are hard and come into the market under the name of compact, cut , or filled soaps.

Commonly considered, soap is, according to its quality and the use for which it is intended, a

A M bansvoosT si aninaoYl^ rfolrfw aionl lovpiX acfaaw

ttatj nl iftiv iljiab el navooe-r aJtrfv bos ,^oiriiOTq-"\Cc'

aixfJ aoqtf atio* latnacilT^qxa iwo gntcftTOBsJa aiolaff ,11

-oTq Tlo.-W ,i£T9neg nl sqcoa aauaalD XXir aw toattfus

-rwin 'lis/? To^ ri/ jcr^n-ii; ^'"if^ t *.'f;)j3r^ ^rf* hi.fl ,unt.tiinno^

-rcc j r:'* -i^ ,i.?o--. .G ,iio?^q9oo« fot'riG ait nl

tii tr ^mulooo TO nvulsaa^oq tarfita ,1I«^I4 rtii lo bm/oq

,(sO*cH6xO)oiaIo rfilv ^iXXatoa^P' , abloa x***^ narfsirf erf*

.aJblo« (HOOOecHrx^) oliaata bn» , (HOOOxcHax^) oUlnlMq

rf^lw btoM \,itMT: A lo bmroqraoo aX^uIoanl arf* jtovavoH

aiaxii ,aXqiaAxa *to^ .qjsoe ja bactna* oaX^ ai: iBinn xvaif m

no-'! f^vaorteifq tdi )o "ra^aaXq JweX to qaoe b«eX ari^ e(

il'^q arfi at bfui jala^b nt baat: aqaoa muimcirfo oka

-liffuX to larotoiifi « as baat; q«oa antmuXa ,8aXMxa^ lo

rfsa^oq 10 asjiaaa^o^ .rfoi/a -rarf.^o yaan bna ,sXto ^nl^ao

,aq«oa l^oa s<t nwoiul ata baa ,*^oa ^lauvu aTa aq/ioa

ard o^nl amoo bruB biaif aia aqaon mboz "to nriJkoa aXlifv

.aqxoa baXXll 10 , tiro ,*aAqinoo to eman ar'^ Tt^biw iaiiafx

oi snibioooa , ai q*)0B ,baTaJkiBnoo ^XnomBoC

A (bsbna^ni al #1 rfoiif'f -^ot aau »H5 biu» \.*lXaup at!

-4-

mechanlcal mixture of the above mentioned compounds, with varying proportions of wate*, with soluble alkali compounds of the rosin acids, with sal soda, with sod- ium silicate or soluble glass, or with other Inert, detersive, or odoriferous agents. Incorporated for the purpose of cheapening the product. Improving Its ap- pearance, Increasing Its detersive action, or overcom- ing Its natural odor with an agreeable perfume. Among the adulterants benefiting or harming a soap, are, ochre, ultramarine, sodium alumlnate, borax, gelatine, resin, vermllllon, copper ai-senlte, alcohol, vaseline, tar, sxigar, chanphor, petroleum, phenol, naphthalene, bran, starch, etc. Therefore, commercial soap is a mix- ture of pure soap with a dilutent, as water, with body imparting substajices, as talc, starch, or petroleum residue; or with detersive agents in aqueous solution/ as sodiian carbonate, borax, or sodium silicate. These additions may all be present in a single soap but the nature and amounts of the addition present depends up- on the character of the soap itself and the purpose for which it is intended.

Soaps may be divided into three general classes viz.- laundry or household soaps, generally contain- ing an excess of alkalies in the form of either sodium carbonate or sodium silicate, or free alkali, and resin; toilet or medicated soaps, the best grades of which are free from impurities and free alkali, or contain

JilaTilM sltfuloa rfJlv ^H9iJi\. 1o anol^ioqonq 7>,nt^rt*v rtftw

•iios dityr ,£b08 las AStm ^abioa nisoi erl^ lo 9bauoqtSco

,^i«nl nsrfJ^o r(;tr , :30X3 oldutoa no •^aotXla hktI

8;f^ nol J)9^«ioqnooni , uixxs^va auotsltiODO -to (STlaie^ei)

•<!• 8*1 rjnlvoTqeit ^touboiq »riJ a-it-tnsqjserid lo saoqnuq

-mODtsro "to ,not.*oA STtsts^si) aii sniaastani ,90Jxj8Tfl9q

SaofflA .omuliaq slrrAsats^ n» rii t-vr tobo lBiix^«n att sal

,9"t* (q«0 8 a snlortAff to s«l*1^9ft9rf BJrwtflifoHB ©rft

(•al*«X»S (XAiorf ,9*iintirjJlB mulbos ,9nl*x«iB0iiXu ,9i;[oo

,9nlX9iuv ,Xor{ooX-a ,9Jln9saB laqqoo ,nolXXtitnoy ^nt^m

,9n9X*'^*xfq«n ,Xon9rfq ,i!!U9Xo-T*9q ,iorf(pBSrfo ,nA7^jj3 ,*XJ8t

-xliB « at qsoa Xjiloi9Bimoo ,9nol9i9jrf ,0*9 ^l^ntsiB ,nBTrf

viiorf rfilw ,t9*sw am ,*n9*iiXlb jb rf^lw q«oa 9iuq lo sijj*

fliu9Xo'tv^9q 10 ,iioi»iF. ,9XBi a« , 89r}rui*8(fi/a ^^nltt-aqml

Xnol^uloa airoaup* at a&aa:^ aytatafah rf5lr -^n ;9uola«*i

actarfT .s^AotXla mstboa 10 ,x><*!ocr ,9^«riodhJto nuluoa a*

aiii Su^ qAoa aXsala M at taaaotq 9ff XXa vjtm anotilbisA

-qu abfl9q9h *n9a9iq iioltlbb* 9rft lo afnuonM Imm aiiS&ma

9 8oq*ix/q 9tiS htiM lX«a*l q«OB adi lo la^OMtrndo atlf ao

.b9ba9*nl at tt xfolrfvr 10I s9aa«Io X«i9n8a 9«irf^ o^nl b9blvlb ntf vmm aq«o'>

-nlfl^noo T,ll»T9n9i> , aqitoa bXcri9«x<c •. '

nu^boc iBtitta to tino^ adf tti aatlsilLB lo uosoxe <)rf jnlaan ba» ^tlsUlM tail to ,«*jialXlB auflb' ^»noutsc

[intttr Ic aabans dar , .^isolit £loS

nlJi^nr , ' f«yXA aeil

-5-

mediclnal agents; and commercial soaps, also termed In- dustrial soaps, which may be subdivided into (a) soft soaps, and (b ) hydrated or hard soaps, as has already been mentioned.

The common fats and oils contain the fatty acids in combination with glycerine, termed glycerides , and it is from these that soaps are generally made. Saponification is the term applied to the process of decomposing the glycerides and forming a soap, and this can be effected in the following ways:-

Aqueous Saponification. This is the most simple and convenient method for the hydrolysis of the glycerides except 'vhen alkalies are used for the sap- onification. The operation may be expressed by the equation: CsHsCCisHssOg) +-2H2O =C3H5(0H)3 -t-SCisHsgOa, the mixture being subjected to the action of Virater or steam at high temperatures or pressures. If the ijirater is acidulated with a dilute mineral acid, the hydrolysis may be accomplished at a much lower temperature, for the acid serves as a catalyzer and accelerates the re- action between the water and the glycerides of the fat. This method is employed chiefly for the manufacture of candle stock, and the preparation of glycerine.

(2) By the action of lime, termed lime sap- onification. This method may be Illustrated by the equation: 2C3H5(Ci8H3502)3 -♦- 3CaO -^-SHaO =3Ca(Ci8H3602)3 +-2C3H5(0H)3, The stock, usually tallow, is melted and

^9Bn9i 08X« ^aqecs l»tcn9toa>r ■ atn^j^ t*nloi.b9m

itos («) oSnl b9btrlb€uB 9d v^r,i doidv ,aq^oe Inl'ximjb \bM9tl£ 9BA km teq«0 8 blMti ic bt^tMtbvr^ {(<) bf^ ,an«o&

.bsnoMnen ns^rf

"Jii^^ 9.-fi ntji^noo alio bra 6^*1 noipjnoo erfT

(••blisoxXr* l)»an»* j^nlTsoyXs ri^lv not J^nlrfmoo at 6^io«

,tbsm vIXiBienexi •tc« aqjBOS ^Arf^ aaorf^ ibot^ si fi btiM

Iro aedootq a/fi o^ baild[q£ rrra^f srf^ aJt aottMoi^tnoqMB

bBM ,q«oe * snlano^ bnM aablTaoYlr »r^^ 8'i'l»<5q"^oo®^

-:8^«r ^nlwoIXo^ 9t^^ nt be^oe^l* acf ft*o Bitii

isoe- arfi al atKT ,noi**ottlnoq«o atroevpA

arfi ^0 %tBx£oriu\t{ »ri^ no^ borfiom tnalnavnoa boe aXt^aila

-qsa 9xfi lol baau stA 8»tX«SX« nex^v ^qaoxe aeclmeoyXs

©ff* ^cf baesonqxe ad" ^jajc noliataqo aifT .not*i»©mnc

♦ sOajHexOC r r(HO)gH50 - ©sHS-^ ( gOgEHeX^) sHcO :neii*upa

no n9^*>'r lo nol^oA ar** o^ b9i09l^ut ^nlatf atu^xira arfl

ttiMv arf^ II .aenueaaiq *io B9itsSat9q/B9f rf^lif ^« bs«^8

•l8^Xo«ii»cH aifi ,bl9« Xiitenia! oiuXM) £ rf:ttv bt>:t«Xi/'bt(Mi al

"Tol ,»Tr'J«T9qBi»;t tawoX liouv fi ** barfalXqmooo^H atf ^ff

-•1 aif^ aataneXeooA bar. nf>rvXjst£o jb a* aanea bt9» ^^-f

• ^«1 arf^ lo aablTaoYX^ 9:*.f boa "leiAw ari^ naaw^arf nck^oM

lo •iwioiJliiruia arfi lol T.Xlalrio bsvoXqe© at boff^om aixfT

• snifeor.XT ^o noi^«t«q9tq erf^ bnti ,3(00^ a alboAo

-qua amlX baan^i j^RtX Ifo not^oa arf^ ",* (S)

•tfi Tcf b»d«n^ai;XXi arf x*ff borf^av ai/fT .nol^«oitlne

£(sOe5Mex3)«afi ■ OsKC-^ 0«OC +.g(- OS mol^wpa

bmi b^JX9m el ,woIXiJ^ y.XXi'ifPU ,:<ooio <»iL Sv

-6-

then run Into the digester together with the llae that has been prevloiisly thoroughly mixed with water. The quantity of unslacked lime commonly used for the sap- onification is from 2 to 4 percent of the weight of the tallow, for, although 8,7 percent is theoreticsdly required, the above amount has been fo\uid to be suf- ficient in practice. The charge, having been added, the digester is closed and the steam turned on, and main- tained at a pressure of from 8 to 10 atmospheres for a period of from 4 to 10 hours, or until saponification is complete, whereupon, the contents of the digester are blown into wooden tanks. After a time the mass re- solves itself into two layers, the supernatant lime "rock" consisting of lime soap and fatty acids, and the "sweet" water, in which is dissolved the glycerine, liberated as shown in the above equation. This glycerine solution is allowed to flow to the glycerine plant where it is treated as described in part 11.

93- Acid Saponification. The melted raw mater- ial is rxin Into a lead lined tank and treated with 4

to 12 percent of concentrated sulphuric acid, and the mixture is subjected to the action of superheated steam. After the acidification the liquor is removed and the fatty acids washed tree from all traces of the acid. The following equation illustrates the process :- C3H5(Ci8H3502)3-*-H2S04 -C3H5(S030H) +3(Ci8H3602) .

94- By the action of caxistic alkalies:-

-q«a 9rii 10^ bOBU yXiiowwoo airll b^sfoAltuu; ^o v^t.1rtai;p

vlXaolistosrfJ el 5n©tn«q V.e rf-nuorf*!* ,^ol ,vcclffl;f orii

-^jjs erf oi^ i)nur>* nestf e«ri iiujofjt ©Tocf* sri^ ,b»*\?i;^ i»t

•iiJ fbobtiM nascf nnlvjiri ,8T\-i*rio sriT .ooi^toanq nl inateil

-nl^in i}n« ,no ooini/i eae^e eri^ Dna be nolo si le^eeslJ^

» lol 88iftrfqB0fli« 01 o^ 6 tcoillo eiuese'tq fi im b^alBt

neli«olltnoq«e ll^nu nc ^tnuot^ Of oi t mon^ >o bclteq

neJeeg^J^ "rf* ^o esine^noo »f(^ ,noqite*Ter{w ,e;t»XqiBoo al

-en aaaff sdi BtaiS s i9^1> .aaituti neboov oint xiwoXc' et*

OBilX :fn«^*Xl^^que ttii ^anexMl c^i oint IXea^l aarXofc

•ri^ bns ,abla« \iiM\ bn» q»oa 9r.il Jo «.ni^r;laxion "^(noi"

,»nln39nXT( 9di bevXofteib ai liolrim tit ,^o.f«1^ "tfeoue"

anXneoxXn alxfT ,M>tiMuy% •fo€M •lii at awoffa a« b»:f«*Te(fiX

iruiXq antnooxXr^ 9iii oi wen oi bawolXa al noMwXca

• ii insq nf beditoaeb aji b^imnii at 3 1 eiaxfw

•ne^a« wjii be^ Xeti sifl .nol^Jioi^lnoqaL' bloA -<^C

^ ri^iv beJaa*!^ bruv -^jiMf bnnki bs^I m oSnt lun et Iml

9r<* boa ,blo« otiurfqiLH b9tMiSnnonoo Ko ^naeneq ^X oJ

.ftaeia beiaaiftequB ^o nol^o* eri^ o^ be;toatdit;a ai 9iuSxtm

9t(i biva bevooei ai toupiX eh^ noU^al^lbloa erfJ le^tA

,btoM 9ifi ^o a»o«*i^ XX« noi*^ aen^ beifaaw ablo« x^lsl

• taaeooiq 9iii m9iM'x9ouilt t\oliMup9 -^nlweiXol eifT

.( :'' ' OfiOfOr. SH ♦•fi(sOe5H8XJ5)aHtO

-7-

C3H5(Ci8H3502)3 +3NaOH = C3H5 (0H)3 -»-3Ci8H3502.Na. This • quation representes the reaction employed in ordinary soap making, and will be treated more in detail farther on. The caustic unites with the fatty acid radical to form the soap, and the glycerine is formed as a "by- product TRftiich is recorered from the waste soap liquor.

The first three of these methods are used ■aiilly for the production of fatty acids, the last for soap making. In a general way these four methods illus- trate the methods of the formation of a soap and the chemistry envolred. If the tallow is choosen as the raw material, the yield of solid fatty acids by the lime saponification is from 44 to 48 percent; while the aqueous saponification admits of a slightly higher yield, that is, about 50 percent. Acid saponification yields upwards of 55 percent of fatty acids, and alkali saponification yields about 50 percent. With lime sap- onification practically all of the glycerine, upwards of 10 percent, is obtained, and the same may be said for the alkali saponification; while with the acid sap- onification not more than 3 percent is recovered,

" The chemistry of saponification was first explained by Cheyreul, who attributed the cleansing action of soap to the free alkali formed by the decom- position of the soap when brought into solution, Krafft and Stem confirm this, and hold that in the hot dilute soap solution, part of the soap is dissociated into

i«ri^*xjl XIaiftft at •nem b9iM9ii »» XXtvr i» , t.r^ qiios

o;f X^nitoAi btoa y^ii*'^ stli Kilv ae^ini/ oi^auAo 9i(^ .no

«Xo' « ti« bsmot si »nl':90iy;I'n srf:^ oii« ,qM>m ntH anol

.loupii q«o« e^Mv sffi aoi^ bftievooa-r ai ifalrfir ^aubotq

bsBU 9-ui •i>erf;teci •ashi to ••nrfJ irtll srf

not 78«I aif^ ,(U»lo« xi^«l to nol^tauJiotq »r(i n»t ^XiiiiUi

-auXXi aboKJaa ti/ot oanri^ ^v XAiene^ « n7 .Ttnl^Ur qaoa

•di biui <|»OB A to Kotiatnoy Btii to oborl^Mi ar^i ^SaiS

•riS an ftSBOOffo bl mollMt orti tT .boTXovua y^t^'-^x^^^

9tii xtf abloA ^c<}i«t biXoR to bXal^ aif^ ,X«t*ie^«B w«n

•riS sXl/fMr ;in«o'i!iq 8^ oi hi' mott ai noti«oltlnoq«e ovrlX

I9t!^tti yX^ifj^lXa « to AlinbJi not;f«oitlnoq«B ovonupm

aot^Aoit tnoq«e bXo/ .;)nao'taq Od 3uo6» , ai 1«H^ ,bX9lr:

tlsiiln ttnti ^tLbloM \iSM\ to inooneq 68 to ab'Uiwqir abXsix

-q«a aaiiX ffilTT .^noortsq OS ^uocC* abXeiic aol^jioittnoq«o

•bipwqu ,»nli©oYXa ©rfJ ^c XX* v,XX*oi^o«nq nol^iioltino

l>i«a od *7Us ame srf^ baa ^o^ntmide al ..taoo^oq OX tc

-<|oa l>lo« orf^ rf.'tr sXtrfw ;nnM4ioltlnoq«a lX«:fI« odi not

• banoTOonn si Jnoon»q r. abr^^ enoin ^on nol^#oXtino

^nil ««v aoli«otttnoq«a to xn^slmaKo tiTl' "

f^nXsiuieXo orli ba^ucTinilA oxfr ,iL-anTOifO xcf bonl^Xqxo

-ffooab axf^ x<^ baanet liintLi oant oif^f o^ q«oft to nof;tob

itt«n:? .aoi^cXott oit nrf aarfr qjioa oifif to noMlaoq

i cl ^«iii bXoK boo ,attli anttnoo onalB beiM

-8-

free acid and free alkali, "but on cooling, the free aold Tinltes with some of the tindlasoclated neutral soap, to form Insoluble bl-palmate, bl-stearate, or other bl-salt, leaving the free alkali In solution. The turbid appearance of the solution may be due to oily drops of the free fatty acids."

Amonge the raw materials used for the manu- facture of soaps are: tallow, grease, and bone stock. These classes may occur in various grades, and in de- termining the quality, buyers as a rule, depend on the simple tests of color, odor, and grain, supplemented by the titer or hardness test, the percentage of mois- ture, melting point, and the percentage of free fatty acids. The raw materials are not necessarily of animal stock as described above, but may be of vegetable origin, as cotton-seed oil, coconut oil, palm oil, palm-kernel oil, corn oil, olive oil, red oil, etc., and in their many modifications.

In the preceedlng discxwsion of the rav/ ma- terials used in soap manufactures, we have considered those bodies which carry two compounds, viz., a glyceride and a caustic alkali, which, when in chemical combina- tion, form a soap. Therefore, soap boiling consists essentially in bringing a fatty body and a caustic alkali in aqueoias solution in contact under suitable conditions, whereby a simple chemical reaction ensues

Xai^u-.i. u' j>;r>c: < X£in»> oirot jf^iV Wt ttUS btUB

cS er " nof:ttrXea lit lo 90iurr«9q<i« Altf^tti?^ -

" . btoB ""JSm^ innrt 9tli \c eqoTb

•9i> ' — , 'bans ai/ol'Mv ni tiiooo ^rar i^eesAlo uaeffT

- '^ ' 'Ortftq sHS f)BvS •eefiDTAri no teJt^ adi y,v

(alTtlio eXcOi^«S9Y '^' '.Mm &ud ,»YOo'e becfl*to«0l> a* "iooi t

Xem83f*eiX«q ,X^r r-iMj ,Xto lunoDoo ,Xto bae8«>no^^oo 8«

'' " ■ " '• )«iT ,XloovlXo fllo tifoo ,Ilo

. ttnoHmol'Mbom vfi»r

•jt ■ ^:i - rfiBi/nniu - i.i u^r'3«»fq 9f'& fll

boiobtonoo •>vi«r. 8.» , a9ti/^ojs^ifn»« q*oa i-i beau oa^m-i- *

9o/i»oxIb • ,.«*▼ , aiiufoqaioo o*i v**!*© r^ol/fr ••lJ»0(f aaorfj

-anl'teoo X^efosiln nt noifw ,{folrfir ,1X«3CX« otStumo m bn»

slalanoo ••-• - - r^om ,«io^ti«i(T .^^^a « tftol ^noli

olitaj»r ^^ — ji •litisnlitf nl YlX«l^nf«aaa

* fua t-d;u; .t:^*-*..!?-' . - nolfutOB mtO^upM ni ttMTf^i»

-9-

with the formation of an alkaline salt of a fatty acid and the liberation of glycerine. The chemical proper- ties of the various glycerldes which constitute the various fats and oils employed in soap manufacture de- termine their behavior in the soap kettle and the var- iation in the amount of alkali absorbed by any part- icular fat or oil is due to the difference in the comp- osition of the glycerldes themselves suid from the vail- ing proportions in which the glycerldes occur in any particular stock. As the molecular weight of the gly- cerldc Increases the amount of alkali necessary for saturation decreases, hence, those commercial fats and oils in nvhich the glycerldes of low molecular weight occur possess the highest alkali absorption in propor- tion to their weight. The greater qixantity of salt required for graining the soap made from such stock is due to the presence of those glycerldes of low mo- lecular weight whose greater solubility in brine of the sodluBtt salt is a marked characteristic. As the glycer- ldes Increase in molecular weight, the solubility in brine of the soap obtained therefrom diminishes, hence, less salt is required for graining.

The manner of effecting the combination or chemical reaction between a fatty body and a caustic alkali and the conditions under which the reaction is completed gives rise to three general classes of soap manufacturing processes, viz.- boiled, semi-boiled, and cold process, whereby soap, to which the same des-

iJifc •txtlfiy J -"ft«joiq Ispit

■'tsr •tli iiiui oifi9ol qaoe erfi ni lelvjiffscr tlexf^ enime^

-Jtjiq va« vn' b9(fioetlM tI»^£M to &suJomf »xtt at aotd»l

oqaoo •f{^ at •ofl»i9llll> 9 LTb si Ho 10 i«) n«Xu9l

'^COA nl tuooo •abtiaoyXr' sr^^ r'otrfw al anot^ioqoiq sni -yXt^ ''i^-t lo tti'^ttt-r TjiXiyoeXon orf^ aA .iCooia naXuoliiJiq nol vtavaea^n tXji>'X« )o ianoiuM trf^ aeasenonl •bfteo eJ^l X/Ioisfntpoo e8exf;t ,9onor( ,a«aji«'to8b nof^^nr^AS ifi^lav ijiXi/oeloin ^roX ^0 ••blieoyX^j nif.f tioltiw at tXle l>n« otoqonq rl noiiqio«((a tiaiiia ictaxfrtixf •lit ataeaoq ttrooo ^X«« )o \iliDMip i»^«»T?) sjlT .Jiislvv ilorf^ 0' ioc^a ifoaa non^ siuiai q«oa •tft &nfA£«*ss **ol ii0titi|>a'i -00 voX )o Babl-ie9V.X:;; eaoffct lo aoneaatq aili oi ajjb at •sii )o anlttf nl xtlltduicm *ia5«an|| aeor- -.-^ i^XuoaX

»i99xlr f'-'S -iA .9i5BlTa^oaTarfo lieiCoaci a ui JXae ourlboa ^1 X^iXlrfirXoa its ,i/lslaw -uXi/oaXoa nl oaffatonl aabl (Sonsxf ,aaifalnliill> mcttvinrit banla^cTo q^Ob arf^ to anlic' • r^nlntats tol baTlvpet al ^Xaa aattX to aoi^«oltfaioo ntii ■Bution'nv to i^nnMm arfT otSyuMO » bOM xP^^ \itMlt » aaav^atf nr>iio»et lt>olB)»iio aoifo»- ^btw mnot&lbnoo or<$ bns i IrnHIs

-.9 8(uiXa li»%&i.0« dc bftieXqr

,1)? lJcr-i«»a ,baXt'' {.»aoo"i 'Mtutu,.

-10-

criptive terms may be applied as iirell, are produced. This classification is arbitrary and is not based on any essential chemical differences in the processes. The division is more mechanical than chemical and has reference chiefly to the time required, the artiflcal heat •mployed, andthe mechanical apparatus necessary to a satisfactory operation of the process.

A cold soap Is one made by the direct comb- ination of the materials In the proportion In which they are to remain in the finished soap, the combina- tion "being effected without the aid of heat other than that required to bring the ingredients to the requi- site tenQ)erature and that heat evolved by the chemical reaction.

Boiled soaps, also called settled soaps, are those ■which in the process of manufacture have been subjected to changes whereby the soap is purified and the glycerine separated.

A semi -boiled or run soap, is one containing all the materials added to the kettle but has not been subjected to the graining process.

The manufacture of a settled soap is accomp- lished in the following steps: (1) saponification; (2) graining suid settling; (3) crutchlng; (4) framing; (5) slabbing; and (6) drying, pressing, etc. These soaps

no ^eaatf Ion «1 baa V«*'«*il<^*W 8-t uoiu*i;oi 11^2*10 alrfT

.ae««e»onq •rii at m»9a»i»Ti\tb imotantio tatiattiav tnii

sAif iMui X«otflS9f{o aadS l^oltiAtio^m 9*ton ei nolclvli» sKT

Xi«olll.^"r« 9rf^ (JkoTtJipo'i snl^ 9di o^ \D«i<{o toavnelgi

'Cisceoosa 9U3»'XMqqB taotn»tio9tR nriShns ,Ji9voX(^« ^«»i1

. 889ootq 9:ii lo rtoM^ttqo ^no^a»1:8l^«a » oi

-''oco rD3Tjti> i»r(^ ^6 9bfim 9no eJt q«08 bXoo A

dolifw nl nol^noqonq 9riS nt tlMitBtmm Bri )o notCAat

-«nl(finoo 9r(i ,q«C(i bgdeinl^ odd nl ni«aoi oi 9i« ^sxfi

.-i«f(j larlio i-^erf iro btm ntlS iuctiitif b9io9ll9 sxii^srf fio^^

-li;p»l 9di c) ainslbon^r* -nliff oj bvili/pai i«f{i

Xj»9lai0ifo 9di x^ i>8vXoT9 i«9."; ^^rf^ boB 9'MJiMfqfnf ails

. ot;?oaat , rjqaoB brXJJoc bglXao c&Xe ,aq«o& bel^o ,. i»tf aya/f aiu*oal!ufUMD lo aeaaonq notttv- oscrfJ

i>n« bai^lTijq ai q«oa arii xtf*"^*^' a9;;ii^i:o c: b»ioat<^vi

.bn^ataqaa bxiXtboyX? - Sxt^niaJnoo ano at ,qacc iiui to beX/ocf-ticaa ' iisatf iot\ mri iud aXii9al a slaXna^ajn sfj liJ»

..■::9ooi:i :xi.iiiihi^ wdi oi baioattft/a

->• al qaoB i.'fi*J9t m \o ant/ioaluiiuir

•: • ;neti«Al^lnoqaf "' IwoXXol ^ni ci berell

;inJtjn»il (^) ;j*xanoJL ;',iitXiiaa bo* jmx^a^^i?

Uiiuoa aaarfT .oia .'inlaaeT;; ,-^aY^o (c*^ *n» ;sn^difaXa

-11-

are the most important and constitute the class most generally manufactured and used. All household soaps are made by this process as veil as the base for toilet soaps, and it is this class of soaps that we produced in the laboratory.

Three stages are required for the complete formation of glycerine and the combination of the al- kali with the fatty acids, by the saponification of the glyceride stock, and each stage mimifests itself in certain characteristic conditions, viz.- the emulsion formed on admixture of the stock and lye, the pasty mass obtained on continued boiling, and lastly, the final condition resulting from boiling the pasty mass with an amount of alkali sufficient for complete sap- onification. These three successive stages of saponi- fication may be represented by the chemical formulas: Raw Materials :

Stearin (tallow) CsHsCCisHs 502)3 Caustic soda:3NaOH

1. anulslon C3H50H(Ci8H3502)2 Soap: CiaHsSO.HaO

Caustic soda: 2NaOH

2. Pasty mass C3H5(0H)2(Ci8H3502) Soap: 2Ci8H350.NaO

Caustic soda: NaOH

3. Glycerine C3H5(0H)3 Soap: 3CiaH350.NaO

Graining. The purpose of graining is to sep- arate the soap from the superfluous water with which it is associated, and which, forming the menstrxmi for

booubonq •* ;t«rfJ 8q«os )o »bm1o , .

X^uBq 9:ii ,oyX ton* :(oo^6 »rfi ^o •'wtxlmhM no bwrtol , IfBMl btiM t^iatltod b9unlinoo no bnalBf cfc aa»tK eaaiD '^^■«q •ff^ finiXlocf flsoil snliXjj«**r no^i^XAnoo X«nll -qiia e^sXquoo toI ^neloXltirs tJ«3(X4i lo ^mroirji lu (f^lir -XnoqBs 1o BenJ>^b svlseflooub oetzti 9«*rfr .nof^AoDlao '.mluanr'i X«otl^9rf^ be^neGeiqcn ecf ^^« nol^aoll

:8X«t*i8^«1! w«H H0*kIK:«b08 olSauM"^ 7:( z^HT.^B 1^) Q^^l^ (wllsi) nlTus^S 0«r/.0i».e;Hfix5 tq*0J ./aOr,r.J'RI^)^^aH50 nolnXurf .X

0*H..O«rH8XOSl tqaoy ( :i^ . "Hbx^^^C W)5HcO BMIi v*M<r ,S

!(0«i( :£bos ol.'at/«0

-qtt oi i ©aoqftr- . n^nt«nO

rfoXifr ffllw n*"** ■ si/ojjXlnoqi;. q#o« nt^J »i»iM

-12-

for the salt, glycerine, lye, impurities in the stock, ttc, constitutes the soap lye. The salt is added either as the dry salt or as a saturated brine, in small quant- ities at a time, to the quietly boiling contents of the kettle and thoroughly boiled with it until a portion taken on a paddle coagulates or separates so that waste lye runs from it. The waste lye should be clear, of a salty taste, and should not contain free alkali In ex- cess of 0.4 percent. This amount of free alkali in ▼aate soap lye is not perceptible to the taste. The more concentrated the salt solution In contact with the soap the less water will be retained by it. In boiling this character of a soap the stock lye should not have a greater density than 13 degrees Baume', and should contain from 7 to 10 percent of salt. This is the loav- es t density that will remove the soap completely from solution, while the stock lye is the clearest and least discolored, and is the most valuable, owing to the high percentage of glycerine present. Wa.cn the desired grain has "been obtained the soap is boiled up to the top of the kettle, the steam turned off, and the contents al- lowed to rest vintil the following morning. Settling. Pitting or settling the soap is the term applied when weak lye or water is added to the soap to

,afoc; Ituqfit ,9\1 . ,

'ioMup tlMnm at ,»fll"icf b^iMivfaa « a» to iX« i om

tituw imAt ot Ae^AtAqea no a0}«Xi/>^oo tllb»<i m no ael«;r

» !to ,"t«wXo ecf feXt/oift ©vl »*a«w »x!T .it botI bxiu- r i

-«9 nl tJjB^lXjs A9*xl ntrinoo ion JbXxrerfe bos .siui \itM%

ni 1X«?(X« ftsil "(0 iauooB bIiT; .indoisrx i^.O lo aaeo

oifT .siMi oni oJ aX^tiqeen^q ion at avX q«oe oioffv

arfi iCtlv totf^ ' no^ijjXoB iXfla srfi bei«tixiaonoo oTon

".nlXtotf al .il X«f l>9ntjisn erf iltr i9fmr taaX affi q^oa

•TAif ion JbXuo/fa ayX >looic srfi qjioa a tt loioatsxfo a£rfi

bXt;o2fa bna ,*e»;«^ 89a*tBaib !:X rcfl/fi x^laAoJi neiaats m

-roX axfi al alrTT .iXaa It inaotaq OX oi r monl nl«inoo

Doit xXaioX(pBOO qaoa arfi avonsi Ill-r i«jii xilaaaib iaa

i«iaX ibn« i'ieijieXo axfi ai a^X sloeia arfi aXirfir ,nolii;Xoa

, %X'r£t;£«T iaon arfi et bna ,boTeXo&BtJb

alaiS ba-tlaab 9rii a»ttV .inaaanq anliao^Xs ^o as^inaotoq

lo qoi a/(i o# qt; asX noa aifi banl«icfo naatf aaxf

'la ainninoo adi bna ,^lo batntri maaie aifi ,eXiie:I 9^3

.^ntmcic "^niiroXXol arfJ llSr\ oi beweX

mei ».:i &t '4MC» %tfi suxiXiiaa to ^aiisn. .antli.'a'J

^9bbJ aJt iei4^ no a>cX stotw . i

-13-

thln It to the desired consistency. The strengthening lye from the preceedlng chemge is withdraira and the soap "boiled up with lire steam to the top of the kettle and It is then allowed to stand for five days, during which time the contents of the kettle, because of the different specific gravities, resolve themselves rough- ly into two portions, viz.- the finished soap carry- ing about 30 percent of water, and the niger, which carries considerably more water than does the super- natant soap, as well as the inipurities and coloring matter settled from it. The niger constitutes from 20 to 25 per cent of the volume of the settled soap in the kettle.

The detergency of soap is greatly Increased by the addition of certain substances called fillers, in aqueous solution, while the soap is still in the fluid condition. The substances used as fillers have already been mentioned, and the nature and amount of the filler determines whether the soap is heavily or lightly filled.

Crutching. For the incoi-poration of the fill- ing material into so^, the belt driven crutcher is generally employed. There are three types of this machine each possessing their several points of excellence, but we will atten5)t to describe only one of them. This

9l3i9:i Biij 10 qei •x& e5 irjB»l& evil lUiw <|u i»tXfocr y^nliub ,rc«l> svt') lol biuiis oi l>ewoiX£ a»if^ si ^t baa

•X*nso qmob tf-.^iafi 9iii -.alT ,«aol;^*ioq oft oial xX

xfoiifv ii*lia *dc bn» ,n«^«w lo ^neontq 01 iuedm %at

-T»qu« eill eeob luiil^ ns^x- ston \Xtf«*xtblaxioo iel*Tt«o

'^nlneXoo btiM adlllTucpsi exf^ &• XXew b« ,<|«oe ^lui^iia

^S aom Mluii^anoo *t«8.tn erfl ,it moil beXiies leiiAc:

fli qaot beX^ita sifi t* smuXoT 9tlS !• ioea *t»f[ SS oi

«9X^^«:C e;fi

bewsnoAi xX^^B'ta >^ qfiOft to xoa^S'^e^sb sriT

, :«XXil b9XX«o BeofLAladiue ntaJieo lo nol^ibb« »x{J x^

• J^t nl XXt^a ei qA06 arf.'^ sXirfv ,col^x:Xoe auoaup* nl

•Taxf B^aXXll 8Ui bnair aaoiw^acfLra aifl .noiilbnoo bluXl

lo ^auoina bna 9iut»a tit i^OM ,banoMaaA naacf xb«9iX«

no xllysttt al qac ^riJarfw oantortalai?

• baXXn tX^n}«lX •IXll -.0 tisio<i^ooai arii n«t .T>nlrio*i;"iO

ai ladoiino ne-rlio JXar , poe old XalteJiUP -.1

onliioiia alc(J !• aaipc^ aathL) aid a-iaifr .baxoXqaia xilAnanoT)

,9oaaXX»oxa to a^aXoq iJinaTaa nlt/fl aAleaaaaoq xfoas

n£ifl .aar:r to aa« xXno atfinoaab o^ ^^p»##S XXtv e^ ^<J(f

-14-

conslsta of a cylindrical ressel in which is moxmted a vertical shaft carrying a series of horizontal pad- dles Tifhlch rotate entirely within the "body of the soap, which remains practically stationary. With this type it is impossible to incorporate air into the mass of the soap as the mixing is done entirely within the bodj'' of the soap. The capacity'' of the crutcher is about 1200 pounds. The liquid soap is transferred to the ci*utcher by means of a pump, generally of the Tabor, Hersey, or Johnson rotary type,

framing. The soap frame consists essentially of an uncoyered box having a capacity of about 1200 pounds and supplied with removeable sheet-steel sides, and ends of wood or sheet steel set on a wooden bottom, which is moiuted on truck wheels. The soap from the crutcher is emptied into the frame and allowed to re- main there iintil it has haifdened, whereupon the sides are removed and the soap allowed to rest on the bottom for several weeks or until the soap has cured, that is, until it has dried. This operation requires a great deal of floor space and is objectional for that reason, and althoiagh this method of curing has so many disad- vantages it is still used almost entirely by soap man- ufactururers , A better method, and the one used by the more up to date plants is the following: The liquid

X908»Y Isotihatl- f.teX8fl09

-aaq SMitios.lioti 1q mttfm m T^l^tM^ Slmiim imokify i

sqx^r slil^ r&iW »yr^aol9mi9 v,XX«ol^ojiTq 8r>ljiaie-T riolifw

^0 88fta 9ri^ o^nl il« 0^«noqftO9Ai ot »Icfl««oqBi si ^1

9ii^ nldiiw \:X«ii^a» anoi> si s^lxlai ntii &« q«cB e-{:t

9f.i ei fcafialunjii* al q«oc blu^ll 9tSl , abmroq OOSX ,TorfiiT 9iii \c \liMittn% tHfusq M lo aitfaoi ^tf tafio^ino

• •<IX* ^si9t noaairioT. no ,vaanaH ^XX«llnA8«« aialaaoo ansYt q^oa ariT •jutlm*i1E

OOSX iuodm ^0 Y^lo«c|Ji9 a ^xiivaif xoo' bsieroonLr aa lo

(•ofela Xae^a-Jaaifb aXcIacvoaaT tiStr balXqqva boM abouoq

fOol^oc< naboor a no ^ea Xaaia ^aaha no boow lo aliaa baa

9ni nonl <|aoa arfT .aXsaffv aloin^ no ba^nuom at riotiir

-an 0^ bavoXXa bD» aoan^ 9d& 9itU bal^qara al tarloi^yro

aaftla erfi noquaie/fv ,l»an(»liiuiif a«i{ ^1 liiau aiarf^ ntam

jBO^^otf a/{^ no iaar oi bavoXXa q»oa 9rtS bnt bavoaiai 9tM

,al fiiif ,ba*ii;o aa/f qaoa axfi ItSnu to aCaaw Xaiaraa nol

oTa a aantupat aoii««iaqo alifT .kalnli aarf ii £t9nv

,no8aa*i iMtii lol iMtioiioelxfo at bn* »dJiqa looX^ lo Xasb

-baaib vttMm oa aaK TUtiii/o lo botiiBtn BtHS fivjJOt^ils bOM

. -nav 90a xtf xXatiJna ^aeF<X« baau XXil* aa^^naT

ar.4 xtf Ikaair eno aHi Ana ,bon'^e«! la^^stf A . a-iaimtfi^oattf

btupiX aiTT t^nlwoXXol 9Hi al a^naXq a4«b mi qpr a^oin

-lb- soap Is run to the upper story of the huilding Into a large vat or tank. Prom this tank it flo\vs by grav- ity over a system of steam heated rollers, seven in number, and each a little closer than the preceedlng one. The soap is spread over the roller in a thin layer or film, from whioh it Is taken by the next roller and so on, until it reaches the last, from which it is re- moved by means of a scraper which breaks it up into thin strips or shavings. These shavings fall onto a belt moving very slowly and >rfiich enters a dryer, which is simply a wooden box about 10 feet high, 8 feet long, and 5 feet wide, supplied with glass windows by means of Tihich the interior can be seen. This dryer is sup- plied with steam pipes, and as the soap travels back and forth on the belt within it it is dried and cured. The whole process requires about an hour. The shavings leaving the dryer fall into a basket, yrhlch when full, is carried to the press, and the chips pressed into large slabs, slmlliar to those coming from the frames. Slabbing. The slabber is a machine for cutting the slab of soap into smaller slabs, and consists of a frame work having a series of horizontal parallel wires at a distance apart corresponding to the width or height of the unpressed bars of soap. The slab of soap motant- ed on a truck is pushed along under the frame of the

~i B neq re a

-TJ»i?) \c. Bvoil il lituti air.: ao'fi »^nmi ->• l«v e^i/tX i)

iii nsvrss ,8*191X01 JD«^«»fl ruio^s lo «t»^«^8 it *I9T0 ^i't

li»«r9«nq srii n«x(i i»aoXo viiill a dosm ^om ,todinua

ne^cAX • J^ 19 Hon df(;r lore teviqa nt qMoe oifr .ono

htiM ToiloT ;rx9a axiit ^cf a93U^ al ^t xfolilw cnonl ^mlil 10

••1 •! il ifolifw not^ ,^a«X 9rfl aedoBei ft £*icat ,no oa

o^ni tpj it ualji9tcf xfoiifw -iaqi»i9o » )o aoaam ^o i^oYoa

a o^no iXal asntvsifa eaoriT .a^ntTAxfa 10 aqii^a nlxf^

ifoiffv (isyi-ib M na^aa tlolsftr hoM xi^oXa ^c^ot :|xitvo(n ^X9(f

,saoX ^aol 6 (if^lrf iaat Oi iuodm xorf noboow « xXaE■^.s at

LrM9m ^tf wcmobatii aaflXj^ ditf ibatXqqua ,aJil-w ^aal d ha*

-qL(» »i noxtik a^'*^ .aaaa atf nao lotia^nl 9ff^ stottfn lo

slaatf aXovatl qAoa •liS m Iuim ,esqlq aiaaia dStw k^tlq

.b9'wo bna bnJnh ut 9t it nttUtir ^XacT »Ai no ilitol bxus

aanlYAifa orfT .-uiorf oe iirodto Mntt/pan aaaMtq aXoifr o/fT

.XXul oarfw riolrfw ,ia4a«(f « o^nl XX«1 f^^b »rti snXraeX

c*nl boaaanq aqirfo 9/1^ firui , asoiq orf^ o^ balTUie aX

• aoais-tl ai(^ «onl tnlnoo eaorii oi -t«lItaiXa ^sdMlt asn^X

9rii ^fltiiuo *iel onltiomm m bI *iatfd«Xa ain* •snXtfd:aX8

a t« a^atanoo JMia ,atfi>Xs loXX^aa o^aX qaoa lo rf^Xa

:9XX/»*!iiq Xa^{iO!tl*xai< lo aaXnaa « snlYiMi aCnow aean'i

.0 tiitiv nris 9i anXi>noqaai*toe itMqft aona^aiib » S»

"iauom (|aoa )o ctaXa ojf7 .qpioa to an^cf ivaaeniqm.

91^^ ^c ecum^ sr:^ i^bnu "naclM berfauq aX ioin^ « no »•

-16-

slaljber and as the soap comes Into it it meets the taut steel wires and is cut into smaller slabs. These slabs are then removed to the cutting table, where each is cut into bars .

Each slab is lifted onto the cutting table and pushed lenghtwise through one or two wire* held in the cutting head, by means of which, it is cut into two or more narrower slabs as wide as the single bar is long. These slabs are then cut at right angles by another attendant to the dimensions corresponding to the width and thickness of a single bar. The individual bars are then slightly separated from one another so that the air may circulate freely around them. When the truck is full of these bars it is removed to the drying room.

The purpose of the drying room is to hasten the evaporation of the water from the surface of the "bar so that there may be formed a thin crust of con^i- aratively hard soap which serves to retard further e- vaporation from the interior of the bar, cuid which al- lows the bar to be pressed and stamped without the soap adhering to the dies . Now there is an xinequal equilib- rium of moisture content between the exterior and in- terior parts of the bar, a partial eaqplanation of the

^-.'n':A- , ttovome'

. eiAo' oini iut> ei

ni. M erfafa towoniAn noic •

X^ ••Xaxui ^rfaii ^« ;tuo n«i /^«X« eavffT .snel. ti

n* • ibnoqMttttoo •notanttsllt Oi rt^bfl»ii« i9tfJena

{^on« ono Mwnl Ao^i'Tatrfi: la narfJ ©n* .

nainr .a!»jf^ iifarota y,lt> . ':itrr tl/' •>:(.*

9/f^ oi b«Tom»*i el ^t rtao 9Bf

.flM>oi salx*ik

fJ95a»r' ,-con r;r - ^rnftrcj «lfP

-ftfBor* to fw-.

bsm:

■toqj»v

'?ecc?>T''

00 f>".t'9^tr:

-17-

Bweating to ivhlch soaps are universally susceptilDle, This accximulation of moisture does not develop until after the "bar is wrapped and packed. With the soap wrapped and packed in a hox the conditions are natur- ally different. The tendency for the moisture to pass from the interior of the "bar to the drier surface re- mains , but further evaporation from the exterior of the bar is checked. Here the moisture accumiilates and soft- ens the soap, which in turn adheres to the wrapper. The drying room is either furnished with ventilating fans or steam or cold air pipes, or both. The require- ments for the drying room are that a large volume of air miust be furnished at the required temperature and be maintained in rapid circulation. A temperature of 80 to 100 degrees P. is productive of the best results.

When the soap comes from the drying room it is ready for pressing. This consists in pressing the cakes of soap into the desired shape and volume, and stamping them with the trade narks etc. The automatic steain.-poY.'er soap press is the one universally used at the present time and they have a guaranteed capacity of from 60,000 to 75,000 cakes per day of 10 hours.

The semi-boiled soap as has already been mentioned is primarily a cheap method of soap manufact- ure, with economy in fuel, labor, and time. It is best,

,v93i'Jtt< T»]^)«

"tVimu an* ea«q of oti/i^iOK oiJ io1 "/JiiebasJ arf. .jnetallli; v.il«

ztintxB •tiS eonl aoii«*io<|«vo nsrt^fi;! iucf ,«fii«>[ >Jlo«> JbiwB s«^s£iiintf09« rru^slon erf} sieH •b«:fo«xfo si "utcf

-••;tjjj>«n srfT .rf^ocf TO ,e«qtq it: o ouie^ .. 1

^■s« *aj 'to •TllOiJiioiq si .? Bsotsoji OOX ' i 1 moot ^n ' a«x{W

sri^ ^ntuB*tq

oint q

\tt( eoe txiJ

. snu

jq amiiio C(

000,0

-18-

however, to give the soap a simple purification by graining It sharply, thus prolonging the time consiaaed In its manufacture "by one day. The process in outline is similiar to that just described, and is the method used exclusively for the manufacture of soft soaps.

The production of soap by the cold process far surpasses all other methods in the economy of every element entering into the cost of production, but it possesses certain paramotint disadvantages, v-'hich rer strict its use to a very limited field. The mechanical equipment required consists simply of tanks containing the fat, oil, and caustic lye, a cintcher in which the Ingredients are mixed, and frames to receive the mix- ture ajid in which the chemical reaction of saponifi- cation continues, if under favorable conditions, to completion. Although this process varies in most of Its details from the manufacture of laundry soaps as we have already described, we shall not attempt to go farther into the discussion of this method, nor shall we give in greater detail the method \ve have just des- cribed, concerning the various modifications, altera- tions, etc., which the different manufactururers xise, for we have covered briefly all the essential points to be observed in the production of a soap in our gen- eral outline of their manufacture.

*n3 859 o'f* rX.

-19-

The method employed In the making of a soap by us in the laboratories of Armour Institute Of Tech- nology was exactly similiar to that which v/e have out- lined under the heading, the manufacture of boiled orsettled soaps, with the exception that our apparatus v;as crude, on a smaller scale, and that we added cotton- seed oil when the saponification had reached the pasty state.

Trlrty five pounds of tallow, having a sap- onification number of 195, was placed in a kettle ajid melted by means of a steam coil placed in the bottom thereof. When the tallo'Ar v/as in the liquid condition we added 20 pounds of our caustic alkali solution con- taining 6 percent of NaOH and then boiled the mixture. After about 10 hours boiling the emulsion stage was completed, that is, the first third of the alkali was then in combination with the tallow (stearin). At the end of the next 15 hours boiling we judged that the pasty state was completed, that is, t'.vo-thirds of the caustic was in combination with the stearin, and at this point v/e added 15 povmds of cotton-seed oil having a saponification number of 137, and 20 poxmds more of the lye. The boiling was then continued for another period of six hours, whereupon the saponification v/as complete, that is, all the alkali was in combination with the s

09it ^'ttMlUii ,

[MOB ooij^earro

, . iXjusB M no ,9btno aatv

I«a srtJ norhT £to b»tt

r«i lo 8l>is/oq 9Tlt ^^nJtnT >«Xq afi .ottMot^iao

jeoaXq Xtoo ms^u

>;Xos lXa3lX« ol^itfjio 1U0 lo aiim/oq OSi i>9jb^; iiaXiod a^ri^ iiiiA RO«i: -ti^r

it A a«- IXaHXa 'slcjiaoo

<!>Si>JL''t 9w J^alltod oa9

"itOiSOO to CilX!

:jtiioq«»

-20-

stearln, for the solution on top boiled very quietly, was frothy and smooth, and the stock v^ould slide from the paddle in large transparent flakes , and Avhen a small portion was rubhed betY;-een the fingers it curled up smooth and drjS without any indication of greaee.

The saponification being complete, the stock was ready for the graining. While the mixture was boil- ing quietly we added a little salt, NaCl, but this small addition soon threw so much soap out of solution that our kettle would not hold it. To overcome this difficulty v/e removed all the soap from the kettle and made up a brine solution y*iich we heated to boiling in the kettle and then added a little of our soap solution and continued the boiling until it was all throvm out of solution, whereupon v:e allowed it to settle and sol- idify, and then removed it, leaving the brine in the kettle for the next lot, adding a little salt each time to make up for that used. Our