Palomaa, Matti H. et al. published their research in Berichte der Deutschen Chemischen Gesellschaft [Abteilung] B: Abhandlungen in 1942 | CAS: 1190-39-2

malonic acid dibutyl ester (cas: 1190-39-2) belongs to esters. Esters are also usually derived from carboxylic acids. It may also be obtained by reaction of acid anhydride or acid halides with alcohols or by the reaction of salts of carboxylic acids with alkyl halides. Because of their lack of hydrogen-bond-donating ability, esters do not self-associate. Consequently, esters are more volatile than carboxylic acids of similar molecular weight.SDS of cas: 1190-39-2

Etherlike compounds. XXVII. Turbid phases in compounds with reactivity minimums was written by Palomaa, Matti H.;Mikkila, Irma. And the article was included in Berichte der Deutschen Chemischen Gesellschaft [Abteilung] B: Abhandlungen in 1942.SDS of cas: 1190-39-2 This article mentions the following:

In a study of the m.ps. and viscosities of esters of the oxalic acid series, it was observed that the esters of CH2(CO2H)2 showed a region of turbidity before they solidified. The m.ps. and clearing points of the esters were: Me2 -61.9°, -42.4°; Et2 -48.9°, -40.3°; Pr2 -77.1°, -62.9°; Bu2 -95 ± 5°, -45.8°; Am2 -54.9°, -34.0°. The dioctyl and di-iso-Pr esters melt clear at -6.3° and -50.7°. Esters of (CO2H)2, (CH2CO2H)2 and (CH2)4(CO2H)2 do not show this behavior; m.ps. of the Me, Et, Pr, Bu and Am esters are given, together with reported values. The viscosity of CH2(CO2Me)2 increased from 34.3 to 178.1 sec. in decreasing its temperature from 20° to -28.8° and from 225.9 to 1716.5 sec. in the range -34.90 to -57°. For the clear phase (20° to -31°) the viscosity of CH2(CO2Am)2 increases from 17.9 to 154.6 sec.; for the turbid phase (-37° to -60°) the change is from 231 to 1896.8 sec. Data are given for the viscosities of (CO2Am)2, CH2(CO2Am)2 and (CH2CO2Am)2, using the same viscometer; the relative viscosity of the last ester is much greater than for the other two. The occurrence of the turbid phase is believed to be the result of a decreased cohesive power because of intermol. or intramol. saturation In the experiment, the researchers used many compounds, for example, malonic acid dibutyl ester (cas: 1190-39-2SDS of cas: 1190-39-2).

malonic acid dibutyl ester (cas: 1190-39-2) belongs to esters. Esters are also usually derived from carboxylic acids. It may also be obtained by reaction of acid anhydride or acid halides with alcohols or by the reaction of salts of carboxylic acids with alkyl halides. Because of their lack of hydrogen-bond-donating ability, esters do not self-associate. Consequently, esters are more volatile than carboxylic acids of similar molecular weight.SDS of cas: 1190-39-2

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics